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DirectX/10.0/Direct3D/字体引擎

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在任何应用程序中，将文本写入屏幕都是一个非常重要的功能。在 DirectX 11 中渲染文本需要您首先了解如何渲染 2D 图像。由于我们在之前的教程中涵盖了这个主题，因此本教程将在此基础上进行构建。

您将需要的第一个东西是您自己的字体图像。我用我想要的字符构建了一个非常简单的字体，并将其放在一个 1024x16 的 DDS 纹理上

如您所见，它包含了所需的基本字符，并且它们都位于单个纹理文件中。我们现在可以构建一个简单的字体引擎，它使用纹理中的索引来根据需要将单个字符绘制到屏幕上。我们在 DirectX 11 中是如何做到这一点的呢？我们是通过构建由两个三角形组成的正方形，然后将纹理中的单个字符渲染到该正方形上。因此，如果我们有一个句子，我们会找出我们需要的字符，为每个字符创建一个正方形，然后将字符渲染到这些正方形上。完成之后，我们将所有正方形渲染到屏幕上，形成该句子。这与我们在之前的教程中用于将 2D 图像渲染到屏幕上的方法相同。

现在，为了索引纹理，我们需要一个文本文件，该文件提供纹理中每个字符的位置和大小。此文本文件将允许字体引擎快速从纹理中获取它需要的像素，以形成可以渲染的字符。以下是此字体纹理的索引文件。

该文件的格式为：[字符的 ASCII 值] [字符] [左纹理 U 坐标] [右纹理 U 坐标] [字符的像素宽度]

32   0.0        0.0         0
33 ! 0.0        0.000976563 1
34 " 0.00195313 0.00488281  3
35 # 0.00585938 0.0136719   8
36 $ 0.0146484  0.0195313   5
37 % 0.0205078  0.0302734   10
38 & 0.03125    0.0390625   8
39 ' 0.0400391  0.0410156   1
40 ( 0.0419922  0.0449219   3
41 ) 0.0458984  0.0488281   3
42 * 0.0498047  0.0546875   5
43 + 0.0556641  0.0625      7
44 , 0.0634766  0.0644531   1
45 - 0.0654297  0.0683594   3
46 . 0.0693359  0.0703125   1
47 / 0.0712891  0.0751953   4
48 0 0.0761719  0.0820313   6
49 1 0.0830078  0.0859375   3
50 2 0.0869141  0.0927734   6
51 3 0.09375    0.0996094   6
52 4 0.100586   0.106445    6
53 5 0.107422   0.113281    6
54 6 0.114258   0.120117    6
55 7 0.121094   0.126953    6
56 8 0.12793    0.133789    6
57 9 0.134766   0.140625    6
58 : 0.141602   0.142578    1
59 ; 0.143555   0.144531    1
60  0.160156   0.166016    6
63 ? 0.166992   0.171875    5
64 @ 0.172852   0.18457     12
65 A 0.185547   0.194336    9
66 B 0.195313   0.202148    7
67 C 0.203125   0.209961    7
68 D 0.210938   0.217773    7
69 E 0.21875    0.225586    7
70 F 0.226563   0.232422    6
71 G 0.233398   0.241211    8
72 H 0.242188   0.249023    7
73 I 0.25       0.250977    1
74 J 0.251953   0.256836    5
75 K 0.257813   0.265625    8
76 L 0.266602   0.272461    6
77 M 0.273438   0.282227    9
78 N 0.283203   0.290039    7
79 O 0.291016   0.298828    8
80 P 0.299805   0.306641    7
81 Q 0.307617   0.31543     8
82 R 0.316406   0.323242    7
83 S 0.324219   0.331055    7
84 T 0.332031   0.338867    7
85 U 0.339844   0.34668     7
86 V 0.347656   0.356445    9
87 W 0.357422   0.370117    13
88 X 0.371094   0.37793     7
89 Y 0.378906   0.385742    7
90 Z 0.386719   0.393555    7
91 [ 0.394531   0.396484    2
92 \ 0.397461   0.401367    4
93 ] 0.402344   0.404297    2
94 ^ 0.405273   0.410156    5
95 _ 0.411133   0.417969    7
96 ` 0.418945   0.420898    2
97 a 0.421875   0.426758    5
98 b 0.427734   0.432617    5
99 c 0.433594   0.438477    5
100 d 0.439453  0.444336    5
101 e 0.445313  0.450195    5
102 f 0.451172  0.455078    4
103 g 0.456055  0.460938    5
104 h 0.461914  0.466797    5
105 i 0.467773  0.46875     1
106 j 0.469727  0.472656    3
107 k 0.473633  0.478516    5
108 l 0.479492  0.480469    1
109 m 0.481445  0.490234    9
110 n 0.491211  0.496094    5
111 o 0.49707   0.501953    5
112 p 0.50293   0.507813    5
113 q 0.508789  0.513672    5
114 r 0.514648  0.517578    3
115 s 0.518555  0.523438    5
116 t 0.524414  0.527344    3
117 u 0.52832   0.533203    5
118 v 0.53418   0.539063    5
119 w 0.540039  0.548828    9
120 x 0.549805  0.554688    5
121 y 0.555664  0.560547    5
122 z 0.561523  0.566406    5
123 { 0.567383  0.570313    3
124 | 0.571289  0.572266    1
125 } 0.573242  0.576172    3
126 ~ 0.577148  0.583984    7

有了索引文件和纹理文件，我们就有了构建字体引擎所需的一切。如果您需要构建自己的索引文件，请确保每个字符之间只用空格分隔，并且您可以自己编写位图解析器，根据没有空白的位置创建 TU 和 TV 坐标。

请记住，不同的用户将在不同的分辨率下运行您的应用程序。一个大小的字体无法在所有分辨率下都清晰可读。因此，您可能需要制作 3-4 种不同的字体大小，并在特定分辨率下使用特定大小的字体来解决此问题。

框架

[编辑 | 编辑源代码]

由于我们希望将字体功能封装在它自己的类集中，因此我们将向我们的框架添加一些新类。更新后的框架如下所示

在本教程中，我们有三个新类，分别称为 TextClass、FontClass 和 FontShader 类。FontShaderClass 是用于渲染字体的着色器，类似于 TextureShaderClass 在之前教程中用于渲染位图图像的方式。FontClass 保存字体数据并构造渲染字符串所需的顶点缓冲区。TextClass 包含每个需要渲染到屏幕的文本字符串集的顶点和索引缓冲区，它使用 FontClass 创建字符串的顶点缓冲区，然后使用 FontShaderClass 渲染这些缓冲区。

Fontclass.h

[编辑 | 编辑源代码]

我们将首先查看新的 FontClass。此类将处理字体的纹理、来自文本文件的字体数据以及用于使用字体数据构建顶点缓冲区的函数。保存单个句子字体数据的顶点缓冲区将位于 TextClass 中，而不是此类中。

////////////////////////////////////////////////////////////////////////////////
// Filename: fontclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _FONTCLASS_H_
#define _FONTCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <d3d11.h>
#include <d3dx10math.h>
#include <fstream>
using namespace std;


///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "textureclass.h"


////////////////////////////////////////////////////////////////////////////////
// Class name: FontClass
////////////////////////////////////////////////////////////////////////////////
class FontClass
{
private:

FontType 结构用于保存从字体索引文件中读取的索引数据。left 和 right 是 TU 纹理坐标。size 是字符的像素宽度。

	struct FontType
	{
		float left, right;
		int size;
	};

VertexType 结构用于实际的顶点数据，这些数据用于构建渲染文本字符的正方形。单个字符将需要两个三角形才能构成一个正方形。这些三角形将只有位置和纹理数据。

	struct VertexType
	{
		D3DXVECTOR3 position;
		D3DXVECTOR2 texture;
	};

public:
	FontClass();
	FontClass(const FontClass&);
	~FontClass();

	bool Initialize(ID3D11Device*, char*, WCHAR*);
	void Shutdown();

	ID3D11ShaderResourceView* GetTexture();

BuildVertexArray 将处理构建和返回一个三角形顶点数组，该数组将渲染作为输入传递给此函数的字符句子。此函数将由新的 TextClass 调用，以构建它需要渲染的所有句子的顶点数组。

	void BuildVertexArray(void*, char*, float, float);

private:
	bool LoadFontData(char*);
	void ReleaseFontData();
	bool LoadTexture(ID3D11Device*, WCHAR*);
	void ReleaseTexture();

private:
	FontType* m_Font;
	TextureClass* m_Texture;
};

#endif

Fontclass.cpp

[编辑 | 编辑源代码]
///////////////////////////////////////////////////////////////////////////////
// Filename: fontclass.cpp
///////////////////////////////////////////////////////////////////////////////
#include "fontclass.h"

类构造函数将 FontClass 的所有私有成员变量初始化为 null。

FontClass::FontClass()
{
	m_Font = 0;
	m_Texture = 0;
}


FontClass::FontClass(const FontClass& other)
{
}


FontClass::~FontClass()
{
}

Initialize 将加载字体数据和字体纹理。

bool FontClass::Initialize(ID3D11Device* device, char* fontFilename, WCHAR* textureFilename)
{
	bool result;


	// Load in the text file containing the font data.
	result = LoadFontData(fontFilename);
	if(!result)
	{
		return false;
	}

	// Load the texture that has the font characters on it.
	result = LoadTexture(device, textureFilename);
	if(!result)
	{
		return false;
	}

	return true;
}

Shutdown 将释放字体数据和字体纹理。

void FontClass::Shutdown()
{
	// Release the font texture.
	ReleaseTexture();

	// Release the font data.
	ReleaseFontData();

	return;
}

LoadFontData 函数是我们在其中加载包含纹理索引信息的 fontdata.txt 文件的地方。

bool FontClass::LoadFontData(char* filename)
{
	ifstream fin;
	int i;
	char temp;

首先，我们创建一个 FontType 结构数组。数组的大小设置为 95，因为纹理中有 95 个字符，因此 fontdata.txt 文件中有 95 个索引。

	// Create the font spacing buffer.
	m_Font = new FontType[95];
	if(!m_Font)
	{
		return false;
	}

现在，我们打开文件并将每一行读取到数组 m_Font 中。我们只需要读取纹理 TU 左右坐标以及字符的像素大小。

	// Read in the font size and spacing between chars.
	fin.open(filename);
	if(fin.fail())
	{
		return false;
	}

	// Read in the 95 used ascii characters for text.
	for(i=0; i> m_Font[i].left;
		fin >> m_Font[i].right;
		fin >> m_Font[i].size;
	}

	// Close the file.
	fin.close();

	return true;
}

ReleaseFontData 函数释放保存纹理索引数据的数组。

void FontClass::ReleaseFontData()
{
	// Release the font data array.
	if(m_Font)
	{
		delete [] m_Font;
		m_Font = 0;
	}

	return;
}

LoadTexture 函数将 font.dds 文件读取到纹理着色器资源中。这将是我们从中获取字符并将其写入它们自己的正方形多边形以进行渲染的纹理。

bool FontClass::LoadTexture(ID3D11Device* device, WCHAR* filename)
{
	bool result;


	// Create the texture object.
	m_Texture = new TextureClass;
	if(!m_Texture)
	{
		return false;
	}

	// Initialize the texture object.
	result = m_Texture->Initialize(device, filename);
	if(!result)
	{
		return false;
	}

	return true;
}

ReleaseTexture 函数释放用于字体的纹理。

void FontClass::ReleaseTexture()
{
	// Release the texture object.
	if(m_Texture)
	{
		m_Texture->Shutdown();
		delete m_Texture;
		m_Texture = 0;
	}

	return;
}

GetTexture 返回字体纹理接口，以便可以渲染字体图形。

ID3D11ShaderResourceView* FontClass::GetTexture()
{
	return m_Texture->GetTexture();
}

BuildVertexArray 将由 TextClass 调用，以使用它作为输入发送的文本句子构建顶点缓冲区。这样，TextClass 中每个需要绘制的句子都有自己的顶点缓冲区，这些缓冲区在创建后可以轻松渲染。输入的 vertices 是指向将在构建后返回给 TextClass 的顶点数组的指针。输入的 sentence 是将用于创建顶点数组的文本句子。输入变量 drawX 和 drawY 是在屏幕上绘制句子的坐标。

void FontClass::BuildVertexArray(void* vertices, char* sentence, float drawX, float drawY)
{
	VertexType* vertexPtr;
	int numLetters, index, i, letter;


	// Coerce the input vertices into a VertexType structure.
	vertexPtr = (VertexType*)vertices;

	// Get the number of letters in the sentence.
	numLetters = (int)strlen(sentence);

	// Initialize the index to the vertex array.
	index = 0;

以下循环现在将构建顶点和索引数组。它从句子中获取每个字符并为其创建两个三角形。然后，它使用 m_Font 数组（包含 TU 纹理坐标和像素大小）将纹理中的字符映射到这两个三角形上。创建该字符的多边形后，它会更新在屏幕上绘制下一个字符的 X 坐标。

	// Draw each letter onto a quad.
	for(i=0; i<numLetters; i++)
	{
		letter = ((int)sentence[i]) - 32;

		// If the letter is a space then just move over three pixels.
		if(letter == 0)
		{
			drawX = drawX + 3.0f;
		}
		else
		{
			// First triangle in quad.
			vertexPtr[index].position = D3DXVECTOR3(drawX, drawY, 0.0f);  // Top left.
			vertexPtr[index].texture = D3DXVECTOR2(m_Font[letter].left, 0.0f);
			index++;

			vertexPtr[index].position = D3DXVECTOR3((drawX + m_Font[letter].size), (drawY - 16), 0.0f);  // Bottom right.
			vertexPtr[index].texture = D3DXVECTOR2(m_Font[letter].right, 1.0f);
			index++;

			vertexPtr[index].position = D3DXVECTOR3(drawX, (drawY - 16), 0.0f);  // Bottom left.
			vertexPtr[index].texture = D3DXVECTOR2(m_Font[letter].left, 1.0f);
			index++;

			// Second triangle in quad.
			vertexPtr[index].position = D3DXVECTOR3(drawX, drawY, 0.0f);  // Top left.
			vertexPtr[index].texture = D3DXVECTOR2(m_Font[letter].left, 0.0f);
			index++;

			vertexPtr[index].position = D3DXVECTOR3(drawX + m_Font[letter].size, drawY, 0.0f);  // Top right.
			vertexPtr[index].texture = D3DXVECTOR2(m_Font[letter].right, 0.0f);
			index++;

			vertexPtr[index].position = D3DXVECTOR3((drawX + m_Font[letter].size), (drawY - 16), 0.0f);  // Bottom right.
			vertexPtr[index].texture = D3DXVECTOR2(m_Font[letter].right, 1.0f);
			index++;

			// Update the x location for drawing by the size of the letter and one pixel.
			drawX = drawX + m_Font[letter].size + 1.0f;
		}
	}

	return;
}

Font.vs

[编辑 | 编辑源代码]

字体顶点着色器只是之前教程中用于渲染 2D 图像的纹理顶点着色器的修改版本。唯一的更改是顶点着色器名称。

////////////////////////////////////////////////////////////////////////////////
// Filename: font.vs
////////////////////////////////////////////////////////////////////////////////


/////////////
// GLOBALS //
/////////////
cbuffer PerFrameBuffer
{
    matrix worldMatrix;
    matrix viewMatrix;
    matrix projectionMatrix;
};


//////////////
// TYPEDEFS //
//////////////
struct VertexInputType
{
    float4 position : POSITION;
    float2 tex : TEXCOORD0;
};

struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
};


////////////////////////////////////////////////////////////////////////////////
// Vertex Shader
////////////////////////////////////////////////////////////////////////////////
PixelInputType FontVertexShader(VertexInputType input)
{
    PixelInputType output;
    

    // Change the position vector to be 4 units for proper matrix calculations.
    input.position.w = 1.0f;

    // Calculate the position of the vertex against the world, view, and projection matrices.
    output.position = mul(input.position, worldMatrix);
    output.position = mul(output.position, viewMatrix);
    output.position = mul(output.position, projectionMatrix);
    
    // Store the texture coordinates for the pixel shader.
    output.tex = input.tex;
    
    return output;
}

Font.ps

[编辑 | 编辑源代码]
////////////////////////////////////////////////////////////////////////////////
// Filename: font.ps
////////////////////////////////////////////////////////////////////////////////


/////////////
// GLOBALS //
/////////////
Texture2D shaderTexture;
SamplerState SampleType;

我们有一个新的常量缓冲区，其中包含 pixelColor 值。我们使用它来控制将用于绘制字体文本的像素的颜色。

cbuffer PixelBuffer
{
    float4 pixelColor;
};


//////////////
// TYPEDEFS //
//////////////
struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
};

FontPixelShader 首先对字体纹理进行采样以获取像素。如果它采样的是黑色像素，则它只是背景三角形的一部分，而不是文本像素。在这种情况下，我们将该像素的 alpha 设置为零，因此当计算混合时，它将确定该像素应该是透明的。如果输入像素的颜色不是黑色，则它是文本像素。在这种情况下，我们将它乘以 pixelColor 以获得我们想要的颜色的像素，然后将其绘制到屏幕上。

////////////////////////////////////////////////////////////////////////////////
// Pixel Shader
////////////////////////////////////////////////////////////////////////////////
float4 FontPixelShader(PixelInputType input) : SV_TARGET
{
    float4 color;
	
	
    // Sample the texture pixel at this location.
    color = shaderTexture.Sample(SampleType, input.tex);
	
    // If the color is black on the texture then treat this pixel as transparent.
    if(color.r == 0.0f)
    {
        color.a = 0.0f;
    }
	
    // If the color is other than black on the texture then this is a pixel in the font so draw it using the font pixel color.
    else
    {
        color.a = 1.0f;
        color = color * pixelColor;
    }

    return color;
}

Fontshaderclass.h

[编辑 | 编辑源代码]

FontShaderClass 只是之前教程中用于渲染字体的 TextureShaderClass，只是重命名并进行了一些代码更改。

////////////////////////////////////////////////////////////////////////////////
// Filename: fontshaderclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _FONTSHADERCLASS_H_
#define _FONTSHADERCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <d3d11.h>
#include <d3dx10math.h>
#include <d3dx11async.h>
#include <fstream>
using namespace std;


////////////////////////////////////////////////////////////////////////////////
// Class name: FontShaderClass
////////////////////////////////////////////////////////////////////////////////
class FontShaderClass
{
private:
	struct ConstantBufferType
	{
		D3DXMATRIX world;
		D3DXMATRIX view;
		D3DXMATRIX projection;
	};

我们有一个新的结构类型，与像素着色器中的 PixleBuffer 相匹配。它只包含将用于渲染文本字体的像素颜色。

	struct PixelBufferType
	{
		D3DXVECTOR4 pixelColor;
	};

public:
	FontShaderClass();
	FontShaderClass(const FontShaderClass&);
	~FontShaderClass();

	bool Initialize(ID3D11Device*, HWND);
	void Shutdown();
	bool Render(ID3D11DeviceContext*, int, D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D11ShaderResourceView*, D3DXVECTOR4);

private:
	bool InitializeShader(ID3D11Device*, HWND, WCHAR*, WCHAR*);
	void ShutdownShader();
	void OutputShaderErrorMessage(ID3D10Blob*, HWND, WCHAR*);

	bool SetShaderParameters(ID3D11DeviceContext*, D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D11ShaderResourceView*, D3DXVECTOR4);
	void RenderShader(ID3D11DeviceContext*, int);

private:
	ID3D11VertexShader* m_vertexShader;
	ID3D11PixelShader* m_pixelShader;
	ID3D11InputLayout* m_layout;
	ID3D11Buffer* m_constantBuffer;
	ID3D11SamplerState* m_sampleState;

FontShaderClass 有一个常量缓冲区，用于存储将用于渲染文本字体的颜色的像素颜色。

	ID3D11Buffer* m_pixelBuffer;
};

#endif

Fontshaderclass.cpp

[编辑 | 编辑源代码]
////////////////////////////////////////////////////////////////////////////////
// Filename: fontshaderclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "fontshaderclass.h"


FontShaderClass::FontShaderClass()
{
	m_vertexShader = 0;
	m_pixelShader = 0;
	m_layout = 0;
	m_constantBuffer = 0;
	m_sampleState = 0;

我们在类构造函数中将像素颜色常量缓冲区初始化为 null。

	m_pixelBuffer = 0;
}


FontShaderClass::FontShaderClass(const FontShaderClass& other)
{
}


FontShaderClass::~FontShaderClass()
{
}


bool FontShaderClass::Initialize(ID3D11Device* device, HWND hwnd)
{
	bool result;

Initialize 加载新的字体顶点着色器和像素着色器 HLSL 文件。

	// Initialize the vertex and pixel shaders.
	result = InitializeShader(device, hwnd, L"../Engine/font.vs", L"../Engine/font.ps");
	if(!result)
	{
		return false;
	}

	return true;
}

Shutdown 调用 ShutdownShader，释放与字体着色器相关的指针和数据。

void FontShaderClass::Shutdown()
{
	// Shutdown the vertex and pixel shaders as well as the related objects.
	ShutdownShader();

	return;
}

Render 将设置着色器参数，然后使用字体着色器绘制缓冲区。请注意，它与 TextureShaderClass 相同，只是它接受了新的 pixelColor 参数。

bool FontShaderClass::Render(ID3D11DeviceContext* deviceContext, int indexCount, D3DXMATRIX worldMatrix, D3DXMATRIX viewMatrix, 
			     D3DXMATRIX projectionMatrix, ID3D11ShaderResourceView* texture, D3DXVECTOR4 pixelColor)
{
	bool result;


	// Set the shader parameters that it will use for rendering.
	result = SetShaderParameters(deviceContext, worldMatrix, viewMatrix, projectionMatrix, texture, pixelColor);
	if(!result)
	{
		return false;
	}

	// Now render the prepared buffers with the shader.
	RenderShader(deviceContext, indexCount);

	return true;
}

InitializeShader 函数加载新的 HLSL 字体顶点和像素着色器，以及与着色器交互的指针。

bool FontShaderClass::InitializeShader(ID3D11Device* device, HWND hwnd, WCHAR* vsFilename, WCHAR* psFilename)
{
	HRESULT result;
	ID3D10Blob* errorMessage;
	ID3D10Blob* vertexShaderBuffer;
	ID3D10Blob* pixelShaderBuffer;
	D3D11_INPUT_ELEMENT_DESC polygonLayout[2];
	unsigned int numElements;
	D3D11_BUFFER_DESC constantBufferDesc;
	D3D11_SAMPLER_DESC samplerDesc;
	D3D11_BUFFER_DESC pixelBufferDesc;


	// Initialize the pointers this function will use to null.
	errorMessage = 0;
	vertexShaderBuffer = 0;
	pixelShaderBuffer = 0;

顶点着色器的名称已更改为 FontVertexShader。

	// Compile the vertex shader code.
	result = D3DX11CompileFromFile(vsFilename, NULL, NULL, "FontVertexShader", "vs_5_0", D3D10_SHADER_ENABLE_STRICTNESS, 0, NULL, 
				       &vertexShaderBuffer, &errorMessage, NULL);
	if(FAILED(result))
	{
		// If the shader failed to compile it should have writen something to the error message.
		if(errorMessage)
		{
			OutputShaderErrorMessage(errorMessage, hwnd, vsFilename);
		}
		// If there was  nothing in the error message then it simply could not find the shader file itself.
		else
		{
			MessageBox(hwnd, vsFilename, L"Missing Shader File", MB_OK);
		}

		return false;
	}

像素着色器的名称已更改为 FontPixelShader。

	// Compile the pixel shader code.
	result = D3DX11CompileFromFile(psFilename, NULL, NULL, "FontPixelShader", "ps_5_0", D3D10_SHADER_ENABLE_STRICTNESS, 0, NULL, 
				       &pixelShaderBuffer, &errorMessage, NULL);
	if(FAILED(result))
	{
		// If the shader failed to compile it should have writen something to the error message.
		if(errorMessage)
		{
			OutputShaderErrorMessage(errorMessage, hwnd, psFilename);
		}
		// If there was  nothing in the error message then it simply could not find the file itself.
		else
		{
			MessageBox(hwnd, psFilename, L"Missing Shader File", MB_OK);
		}

		return false;
	}

	// Create the vertex shader from the buffer.
	result = device->CreateVertexShader(vertexShaderBuffer->GetBufferPointer(), vertexShaderBuffer->GetBufferSize(), NULL, 
					    &m_vertexShader);
	if(FAILED(result))
	{
		return false;
	}

	// Create the vertex shader from the buffer.
	result = device->CreatePixelShader(pixelShaderBuffer->GetBufferPointer(), pixelShaderBuffer->GetBufferSize(), NULL, 
					   &m_pixelShader);
	if(FAILED(result))
	{
		return false;
	}

	// Create the vertex input layout description.
	// This setup needs to match the VertexType structure in the ModelClass and in the shader.
	polygonLayout[0].SemanticName = "POSITION";
	polygonLayout[0].SemanticIndex = 0;
	polygonLayout[0].Format = DXGI_FORMAT_R32G32B32_FLOAT;
	polygonLayout[0].InputSlot = 0;
	polygonLayout[0].AlignedByteOffset = 0;
	polygonLayout[0].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;
	polygonLayout[0].InstanceDataStepRate = 0;

	polygonLayout[1].SemanticName = "TEXCOORD";
	polygonLayout[1].SemanticIndex = 0;
	polygonLayout[1].Format = DXGI_FORMAT_R32G32_FLOAT;
	polygonLayout[1].InputSlot = 0;
	polygonLayout[1].AlignedByteOffset = D3D11_APPEND_ALIGNED_ELEMENT;
	polygonLayout[1].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;
	polygonLayout[1].InstanceDataStepRate = 0;

	// Get a count of the elements in the layout.
	numElements = sizeof(polygonLayout) / sizeof(polygonLayout[0]);

	// Create the vertex input layout.
	result = device->CreateInputLayout(polygonLayout, numElements, vertexShaderBuffer->GetBufferPointer(), 
					   vertexShaderBuffer->GetBufferSize(), &m_layout);
	if(FAILED(result))
	{
		return false;
	}

	// Release the vertex shader buffer and pixel shader buffer since they are no longer needed.
	vertexShaderBuffer->Release();
	vertexShaderBuffer = 0;

	pixelShaderBuffer->Release();
	pixelShaderBuffer = 0;

	// Setup the description of the dynamic constant buffer that is in the vertex shader.
	constantBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	constantBufferDesc.ByteWidth = sizeof(ConstantBufferType);
	constantBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
	constantBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	constantBufferDesc.MiscFlags = 0;
	constantBufferDesc.StructureByteStride = 0;

	// Create the constant buffer pointer so we can access the vertex shader constant buffer from within this class.
	result = device->CreateBuffer(&constantBufferDesc, NULL, &m_constantBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Create a texture sampler state description.
	samplerDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;
	samplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;
	samplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;
	samplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;
	samplerDesc.MipLODBias = 0.0f;
	samplerDesc.MaxAnisotropy = 1;
	samplerDesc.ComparisonFunc = D3D11_COMPARISON_ALWAYS;
	samplerDesc.BorderColor[0] = 0;
	samplerDesc.BorderColor[1] = 0;
	samplerDesc.BorderColor[2] = 0;
	samplerDesc.BorderColor[3] = 0;
	samplerDesc.MinLOD = 0;
	samplerDesc.MaxLOD = D3D11_FLOAT32_MAX;

	// Create the texture sampler state.
	result = device->CreateSamplerState(&samplerDesc, &m_sampleState);
	if(FAILED(result))
	{
		return false;
	}

在这里，我们设置了新的像素颜色常量缓冲区，该缓冲区将允许此类在像素着色器中设置像素颜色。

	// Setup the description of the dynamic pixel constant buffer that is in the pixel shader.
	pixelBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	pixelBufferDesc.ByteWidth = sizeof(PixelBufferType);
	pixelBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
	pixelBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	pixelBufferDesc.MiscFlags = 0;
	pixelBufferDesc.StructureByteStride = 0;

	// Create the pixel constant buffer pointer so we can access the pixel shader constant buffer from within this class.
	result = device->CreateBuffer(&pixelBufferDesc, NULL, &m_pixelBuffer);
	if(FAILED(result))
	{
		return false;
	}

	return true;
}

ShutdownShader 函数释放所有与着色器相关的数据。

void FontShaderClass::ShutdownShader()
{

新的像素颜色常量缓冲区在此处释放。

	// Release the pixel constant buffer.
	if(m_pixelBuffer)
	{
		m_pixelBuffer->Release();
		m_pixelBuffer = 0;
	}

	// Release the sampler state.
	if(m_sampleState)
	{
		m_sampleState->Release();
		m_sampleState = 0;
	}

	// Release the constant buffer.
	if(m_constantBuffer)
	{
		m_constantBuffer->Release();
		m_constantBuffer = 0;
	}

	// Release the layout.
	if(m_layout)
	{
		m_layout->Release();
		m_layout = 0;
	}

	// Release the pixel shader.
	if(m_pixelShader)
	{
		m_pixelShader->Release();
		m_pixelShader = 0;
	}

	// Release the vertex shader.
	if(m_vertexShader)
	{
		m_vertexShader->Release();
		m_vertexShader = 0;
	}

	return;
}

OutputShaderErrorMessage 将任何着色器编译错误写入文本文件，可以在编译失败的情况下进行查看。

void FontShaderClass::OutputShaderErrorMessage(ID3D10Blob* errorMessage, HWND hwnd, WCHAR* shaderFilename)
{
	char* compileErrors;
	unsigned long bufferSize, i;
	ofstream fout;


	// Get a pointer to the error message text buffer.
	compileErrors = (char*)(errorMessage->GetBufferPointer());

	// Get the length of the message.
	bufferSize = errorMessage->GetBufferSize();

	// Open a file to write the error message to.
	fout.open("shader-error.txt");

	// Write out the error message.
	for(i=0; i<bufferSize; i++)
	{
		fout Release();
	errorMessage = 0;

	// Pop a message up on the screen to notify the user to check the text file for compile errors.
	MessageBox(hwnd, L"Error compiling shader.  Check shader-error.txt for message.", shaderFilename, MB_OK);

	return;
}

SetShaderParameters 函数在渲染之前设置所有着色器变量。

bool FontShaderClass::SetShaderParameters(ID3D11DeviceContext* deviceContext, D3DXMATRIX worldMatrix, D3DXMATRIX viewMatrix, 
					  D3DXMATRIX projectionMatrix, ID3D11ShaderResourceView* texture, D3DXVECTOR4 pixelColor)
{
	HRESULT result;
	D3D11_MAPPED_SUBRESOURCE mappedResource;
	ConstantBufferType* dataPtr;
	unsigned int bufferNumber;
	PixelBufferType* dataPtr2;


	// Lock the constant buffer so it can be written to.
	result = deviceContext->Map(m_constantBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
	if(FAILED(result))
	{
		return false;
	}

	// Get a pointer to the data in the constant buffer.
	dataPtr = (ConstantBufferType*)mappedResource.pData;

	// Transpose the matrices to prepare them for the shader.
	D3DXMatrixTranspose(&worldMatrix, &worldMatrix);
	D3DXMatrixTranspose(&viewMatrix, &viewMatrix);
	D3DXMatrixTranspose(&projectionMatrix, &projectionMatrix);

	// Copy the matrices into the constant buffer.
	dataPtr->world = worldMatrix;
	dataPtr->view = viewMatrix;
	dataPtr->projection = projectionMatrix;

	// Unlock the constant buffer.
	deviceContext->Unmap(m_constantBuffer, 0);

	// Set the position of the constant buffer in the vertex shader.
	bufferNumber = 0;

	// Now set the constant buffer in the vertex shader with the updated values.
	deviceContext->VSSetConstantBuffers(bufferNumber, 1, &m_constantBuffer);

	// Set shader texture resource in the pixel shader.
	deviceContext->PSSetShaderResources(0, 1, &texture);

在这里，我们在渲染之前设置像素颜色。我们锁定像素常量缓冲区，然后在其中设置像素颜色，然后再次解锁。我们在像素着色器中设置常量缓冲区位置，它就可以使用。

	// Lock the pixel constant buffer so it can be written to.
	result = deviceContext->Map(m_pixelBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
	if(FAILED(result))
	{
		return false;
	}

	// Get a pointer to the data in the pixel constant buffer.
	dataPtr2 = (PixelBufferType*)mappedResource.pData;

	// Copy the pixel color into the pixel constant buffer.
	dataPtr2->pixelColor = pixelColor;

	// Unlock the pixel constant buffer.
	deviceContext->Unmap(m_pixelBuffer, 0);

	// Set the position of the pixel constant buffer in the pixel shader.
	bufferNumber = 0;

	// Now set the pixel constant buffer in the pixel shader with the updated value.
	deviceContext->PSSetConstantBuffers(bufferNumber, 1, &m_pixelBuffer);

	return true;
}

RenderShader 使用字体着色器绘制准备好的字体顶点/索引缓冲区。

void FontShaderClass::RenderShader(ID3D11DeviceContext* deviceContext, int indexCount)
{
	// Set the vertex input layout.
	deviceContext->IASetInputLayout(m_layout);

	// Set the vertex and pixel shaders that will be used to render the triangles.
	deviceContext->VSSetShader(m_vertexShader, NULL, 0);
	deviceContext->PSSetShader(m_pixelShader, NULL, 0);

	// Set the sampler state in the pixel shader.
	deviceContext->PSSetSamplers(0, 1, &m_sampleState);

	// Render the triangles.
	deviceContext->DrawIndexed(indexCount, 0, 0);

	return;
}

Textclass.h

[编辑 | 编辑源代码]

TextClass 处理应用程序所需的所有 2D 文本绘制。它将 2D 文本渲染到屏幕上，并使用 FontClass 和 FontShaderClass 来帮助它完成此操作。

////////////////////////////////////////////////////////////////////////////////
// Filename: textclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _TEXTCLASS_H_
#define _TEXTCLASS_H_

///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "fontclass.h"
#include "fontshaderclass.h"


////////////////////////////////////////////////////////////////////////////////
// Class name: TextClass
////////////////////////////////////////////////////////////////////////////////
class TextClass
{
private:

SentenceType 是一个结构，它保存每个文本句子的渲染信息。

	struct SentenceType
	{
		ID3D11Buffer *vertexBuffer, *indexBuffer;
		int vertexCount, indexCount, maxLength;
		float red, green, blue;
	};

VertexType 必须与 FontClass 中的 VertexType 相匹配。

	struct VertexType
	{
		D3DXVECTOR3 position;
		D3DXVECTOR2 texture;
	};

public:
	TextClass();
	TextClass(const TextClass&);
	~TextClass();

	bool Initialize(ID3D11Device*, ID3D11DeviceContext*, HWND, int, int, D3DXMATRIX);
	void Shutdown();
	bool Render(ID3D11DeviceContext*, D3DXMATRIX, D3DXMATRIX);

private:
	bool InitializeSentence(SentenceType**, int, ID3D11Device*);
	bool UpdateSentence(SentenceType*, char*, int, int, float, float, float, ID3D11DeviceContext*);
	void ReleaseSentence(SentenceType**);
	bool RenderSentence(ID3D11DeviceContext*, SentenceType*, D3DXMATRIX, D3DXMATRIX);

private:
	FontClass* m_Font;
	FontShaderClass* m_FontShader;
	int m_screenWidth, m_screenHeight;
	D3DXMATRIX m_baseViewMatrix;

在本教程中，我们将使用两个句子。

	SentenceType* m_sentence1;
	SentenceType* m_sentence2;
};

#endif

Textclass.cpp

[编辑 | 编辑源代码]
///////////////////////////////////////////////////////////////////////////////
// Filename: textclass.cpp
///////////////////////////////////////////////////////////////////////////////
#include "textclass.h"

类构造函数将私有成员变量初始化为 null。

TextClass::TextClass()
{
	m_Font = 0;
	m_FontShader = 0;

	m_sentence1 = 0;
	m_sentence2 = 0;
}


TextClass::TextClass(const TextClass& other)
{
}


TextClass::~TextClass()
{
}


bool TextClass::Initialize(ID3D11Device* device, ID3D11DeviceContext* deviceContext, HWND hwnd, int screenWidth, int screenHeight, 
						   D3DXMATRIX baseViewMatrix)
{
	bool result;

存储屏幕大小和基础视图矩阵，这些将用于渲染 2D 文本。

	// Store the screen width and height.
	m_screenWidth = screenWidth;
	m_screenHeight = screenHeight;

	// Store the base view matrix.
	m_baseViewMatrix = baseViewMatrix;

创建并初始化字体对象。

	// Create the font object.
	m_Font = new FontClass;
	if(!m_Font)
	{
		return false;
	}

	// Initialize the font object.
	result = m_Font->Initialize(device, "../Engine/data/fontdata.txt", L"../Engine/data/font.dds");
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the font object.", L"Error", MB_OK);
		return false;
	}

创建并初始化字体着色器对象。

	// Create the font shader object.
	m_FontShader = new FontShaderClass;
	if(!m_FontShader)
	{
		return false;
	}

	// Initialize the font shader object.
	result = m_FontShader->Initialize(device, hwnd);
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the font shader object.", L"Error", MB_OK);
		return false;
	}

创建并初始化将用于本教程的两个字符串。一个字符串在 100, 100 处以白色显示 "Hello"，另一个字符串在 100, 200 处以黄色显示 "Goodbye"。可以调用 UpdateSentence 函数来随时更改字符串的内容、位置和颜色。

	// Initialize the first sentence.
	result = InitializeSentence(&m_sentence1, 16, device);
	if(!result)
	{
		return false;
	}

	// Now update the sentence vertex buffer with the new string information.
	result = UpdateSentence(m_sentence1, "Hello", 100, 100, 1.0f, 1.0f, 1.0f, deviceContext);
	if(!result)
	{
		return false;
	}

	// Initialize the first sentence.
	result = InitializeSentence(&m_sentence2, 16, device);
	if(!result)
	{
		return false;
	}

	// Now update the sentence vertex buffer with the new string information.
	result = UpdateSentence(m_sentence2, "Goodbye", 100, 200, 1.0f, 1.0f, 0.0f, deviceContext);
	if(!result)
	{
		return false;
	}

	return true;
}

Shutdown 函数将释放两个句子、字体对象和字体着色器对象。

void TextClass::Shutdown()
{
	// Release the first sentence.
	ReleaseSentence(&m_sentence1);

	// Release the second sentence.
	ReleaseSentence(&m_sentence2);

	// Release the font shader object.
	if(m_FontShader)
	{
		m_FontShader->Shutdown();
		delete m_FontShader;
		m_FontShader = 0;
	}

	// Release the font object.
	if(m_Font)
	{
		m_Font->Shutdown();
		delete m_Font;
		m_Font = 0;
	}

	return;
}

Render 将绘制两个句子到屏幕上。

bool TextClass::Render(ID3D11DeviceContext* deviceContext, D3DXMATRIX worldMatrix, D3DXMATRIX orthoMatrix)
{
	bool result;


	// Draw the first sentence.
	result = RenderSentence(deviceContext, m_sentence1, worldMatrix, orthoMatrix);
	if(!result)
	{
		return false;
	}

	// Draw the second sentence.
	result = RenderSentence(deviceContext, m_sentence2, worldMatrix, orthoMatrix);
	if(!result)
	{
		return false;
	}

	return true;
}

InitializeSentence 函数创建一个 SentenceType，其中包含一个空的顶点缓冲区，该缓冲区将用于存储和渲染句子。maxLength 输入参数确定顶点缓冲区的大小。所有句子都具有与之关联的顶点和索引缓冲区，这些缓冲区在此函数中首先进行初始化。

bool TextClass::InitializeSentence(SentenceType** sentence, int maxLength, ID3D11Device* device)
{
	VertexType* vertices;
	unsigned long* indices;
	D3D11_BUFFER_DESC vertexBufferDesc, indexBufferDesc;
	D3D11_SUBRESOURCE_DATA vertexData, indexData;
	HRESULT result;
	int i;


	// Create a new sentence object.
	*sentence = new SentenceType;
	if(!*sentence)
	{
		return false;
	}

	// Initialize the sentence buffers to null.
	(*sentence)->vertexBuffer = 0;
	(*sentence)->indexBuffer = 0;

	// Set the maximum length of the sentence.
	(*sentence)->maxLength = maxLength;

	// Set the number of vertices in the vertex array.
	(*sentence)->vertexCount = 6 * maxLength;

	// Set the number of indexes in the index array.
	(*sentence)->indexCount = (*sentence)->vertexCount;

	// Create the vertex array.
	vertices = new VertexType[(*sentence)->vertexCount];
	if(!vertices)
	{
		return false;
	}

	// Create the index array.
	indices = new unsigned long[(*sentence)->indexCount];
	if(!indices)
	{
		return false;
	}

	// Initialize vertex array to zeros at first.
	memset(vertices, 0, (sizeof(VertexType) * (*sentence)->vertexCount));

	// Initialize the index array.
	for(i=0; iindexCount; i++)
	{
		indices[i] = i;
	}

在为句子创建顶点缓冲区描述期间，我们将 Usage 类型设置为动态，因为我们可能想要随时更改句子的内容。

	// Set up the description of the dynamic vertex buffer.
	vertexBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	vertexBufferDesc.ByteWidth = sizeof(VertexType) * (*sentence)->vertexCount;
	vertexBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
	vertexBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	vertexBufferDesc.MiscFlags = 0;
	vertexBufferDesc.StructureByteStride = 0;

	// Give the subresource structure a pointer to the vertex data.
	vertexData.pSysMem = vertices;
	vertexData.SysMemPitch = 0;
	vertexData.SysMemSlicePitch = 0;

	// Create the vertex buffer.
	result = device->CreateBuffer(&vertexBufferDesc, &vertexData, &(*sentence)->vertexBuffer);
	if(FAILED(result))
	{
		return false;
	}

索引缓冲区被设置为一个正常的静态缓冲区，因为其内容永远不需要更改。

	// Set up the description of the static index buffer.
	indexBufferDesc.Usage = D3D11_USAGE_DEFAULT;
	indexBufferDesc.ByteWidth = sizeof(unsigned long) * (*sentence)->indexCount;
	indexBufferDesc.BindFlags = D3D11_BIND_INDEX_BUFFER;
	indexBufferDesc.CPUAccessFlags = 0;
	indexBufferDesc.MiscFlags = 0;
	indexBufferDesc.StructureByteStride = 0;

	// Give the subresource structure a pointer to the index data.
	indexData.pSysMem = indices;
	indexData.SysMemPitch = 0;
	indexData.SysMemSlicePitch = 0;

	// Create the index buffer.
	result = device->CreateBuffer(&indexBufferDesc, &indexData, &(*sentence)->indexBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Release the vertex array as it is no longer needed.
	delete [] vertices;
	vertices = 0;

	// Release the index array as it is no longer needed.
	delete [] indices;
	indices = 0;

	return true;
}

UpdateSentence 更改输入句子的顶点缓冲区的内容。它使用 Map 和 Unmap 函数以及 memcpy 来更新顶点缓冲区的内容。

bool TextClass::UpdateSentence(SentenceType* sentence, char* text, int positionX, int positionY, float red, float green, float blue,
			       ID3D11DeviceContext* deviceContext)
{
	int numLetters;
	VertexType* vertices;
	float drawX, drawY;
	HRESULT result;
	D3D11_MAPPED_SUBRESOURCE mappedResource;
	VertexType* verticesPtr;

设置句子的颜色和大小。

	// Store the color of the sentence.
	sentence->red = red;
	sentence->green = green;
	sentence->blue = blue;

	// Get the number of letters in the sentence.
	numLetters = (int)strlen(text);

	// Check for possible buffer overflow.
	if(numLetters > sentence->maxLength)
	{
		return false;
	}

	// Create the vertex array.
	vertices = new VertexType[sentence->vertexCount];
	if(!vertices)
	{
		return false;
	}

	// Initialize vertex array to zeros at first.
	memset(vertices, 0, (sizeof(VertexType) * sentence->vertexCount));

计算在屏幕上绘制句子的起始位置。

	// Calculate the X and Y pixel position on the screen to start drawing to.
	drawX = (float)(((m_screenWidth / 2) * -1) + positionX);
	drawY = (float)((m_screenHeight / 2) - positionY);

使用 FontClass 和句子信息构建顶点数组。

	// Use the font class to build the vertex array from the sentence text and sentence draw location.
	m_Font->BuildVertexArray((void*)vertices, text, drawX, drawY);

将顶点数组信息复制到句子顶点缓冲区中。

	// Lock the vertex buffer so it can be written to.
	result = deviceContext->Map(sentence->vertexBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
	if(FAILED(result))
	{
		return false;
	}

	// Get a pointer to the data in the vertex buffer.
	verticesPtr = (VertexType*)mappedResource.pData;

	// Copy the data into the vertex buffer.
	memcpy(verticesPtr, (void*)vertices, (sizeof(VertexType) * sentence->vertexCount));

	// Unlock the vertex buffer.
	deviceContext->Unmap(sentence->vertexBuffer, 0);

	// Release the vertex array as it is no longer needed.
	delete [] vertices;
	vertices = 0;

	return true;
}

ReleaseSentence 用于释放句子顶点和索引缓冲区以及句子本身。

void TextClass::ReleaseSentence(SentenceType** sentence)
{
	if(*sentence)
	{
		// Release the sentence vertex buffer.
		if((*sentence)->vertexBuffer)
		{
			(*sentence)->vertexBuffer->Release();
			(*sentence)->vertexBuffer = 0;
		}

		// Release the sentence index buffer.
		if((*sentence)->indexBuffer)
		{
			(*sentence)->indexBuffer->Release();
			(*sentence)->indexBuffer = 0;
		}

		// Release the sentence.
		delete *sentence;
		*sentence = 0;
	}

	return;
}

RenderSentence 函数将句子顶点和索引缓冲区放在输入汇编器上，然后调用 FontShaderClass 对象来绘制作为此函数输入给出的句子。请注意，我们使用 m_baseViewMatrix 而不是当前视图矩阵。这使我们能够在每一帧中将文本绘制到屏幕上的相同位置，而不管当前视图可能在哪里。同样，我们使用 orthoMatrix 而不是常规投影矩阵，因为这应该使用 2D 坐标进行绘制。

bool TextClass::RenderSentence(ID3D11DeviceContext* deviceContext, SentenceType* sentence, D3DXMATRIX worldMatrix, 
			       D3DXMATRIX orthoMatrix)
{
	unsigned int stride, offset;
	D3DXVECTOR4 pixelColor;
	bool result;


	// Set vertex buffer stride and offset.
	stride = sizeof(VertexType); 
	offset = 0;

	// Set the vertex buffer to active in the input assembler so it can be rendered.
	deviceContext->IASetVertexBuffers(0, 1, &sentence->vertexBuffer, &stride, &offset);

	// Set the index buffer to active in the input assembler so it can be rendered.
	deviceContext->IASetIndexBuffer(sentence->indexBuffer, DXGI_FORMAT_R32_UINT, 0);

	// Set the type of primitive that should be rendered from this vertex buffer, in this case triangles.
	deviceContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

	// Create a pixel color vector with the input sentence color.
	pixelColor = D3DXVECTOR4(sentence->red, sentence->green, sentence->blue, 1.0f);

	// Render the text using the font shader.
	result = m_FontShader->Render(deviceContext, sentence->indexCount, worldMatrix, m_baseViewMatrix, orthoMatrix, m_Font->GetTexture(), 
				      pixelColor);
	if(!result)
	{
		false;
	}

	return true;
}

D3dclass.h

[编辑 | 编辑源代码]

在本教程中，我们还修改了 D3DClass 以合并混合状态。混合允许字体与背景中的 3D 对象混合。如果我们不打开混合，我们会看到文本后面的黑色三角形。但混合打开后，只有文本的像素会显示在屏幕上，其余的三角形是完全透明的。这里我不会详细介绍混合，但本教程需要一个简单的混合才能正常工作。

////////////////////////////////////////////////////////////////////////////////
// Filename: d3dclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _D3DCLASS_H_
#define _D3DCLASS_H_


/////////////
// LINKING //
/////////////
#pragma comment(lib, "dxgi.lib")
#pragma comment(lib, "d3d11.lib")
#pragma comment(lib, "d3dx11.lib")
#pragma comment(lib, "d3dx10.lib")


//////////////
// INCLUDES //
//////////////
#include <dxgi.h>
#include <d3dcommon.h>
#include <d3d11.h>
#include <d3dx10math.h>


////////////////////////////////////////////////////////////////////////////////
// Class name: D3DClass
////////////////////////////////////////////////////////////////////////////////
class D3DClass
{
public:
	D3DClass();
	D3DClass(const D3DClass&);
	~D3DClass();

	bool Initialize(int, int, bool, HWND, bool, float, float);
	void Shutdown();
	
	void BeginScene(float, float, float, float);
	void EndScene();

	ID3D11Device* GetDevice();
	ID3D11DeviceContext* GetDeviceContext();

	void GetProjectionMatrix(D3DXMATRIX&);
	void GetWorldMatrix(D3DXMATRIX&);
	void GetOrthoMatrix(D3DXMATRIX&);

	void TurnZBufferOn();
	void TurnZBufferOff();

我们有两个用于打开和关闭 alpha 混合的新函数。

	void TurnOnAlphaBlending();
	void TurnOffAlphaBlending();

private:
	bool m_vsync_enabled;
	
	IDXGISwapChain* m_swapChain;
	ID3D11Device* m_device;
	ID3D11DeviceContext* m_deviceContext;
	ID3D11RenderTargetView* m_renderTargetView;
	ID3D11Texture2D* m_depthStencilBuffer;
	ID3D11DepthStencilState* m_depthStencilState;
	ID3D11DepthStencilView* m_depthStencilView;
	ID3D11RasterizerState* m_rasterState;

	D3DXMATRIX m_projectionMatrix;
	D3DXMATRIX m_worldMatrix;
	D3DXMATRIX m_orthoMatrix;

	ID3D11DepthStencilState* m_depthDisabledStencilState;

我们有两个新的混合状态。m_alphaEnableBlendingState 用于打开 alpha 混合，而 m_alphaDisableBlendingState 用于关闭 alpha 混合。

	ID3D11BlendState* m_alphaEnableBlendingState;
	ID3D11BlendState* m_alphaDisableBlendingState;
};

#endif

D3dclass.cpp

[编辑 | 编辑源代码]

由于前面的教程，我们将只介绍此类中已更改的函数。

////////////////////////////////////////////////////////////////////////////////
// Filename: d3dclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "d3dclass.h"


D3DClass::D3DClass()
{
	m_swapChain = 0;
	m_device = 0;
	m_deviceContext = 0;
	m_renderTargetView = 0;
	m_depthStencilBuffer = 0;
	m_depthStencilState = 0;
	m_depthStencilView = 0;
	m_rasterState = 0;
	m_depthDisabledStencilState = 0;

将两个新的混合状态设置为 null。

	m_alphaEnableBlendingState = 0;
	m_alphaDisableBlendingState = 0;
}


bool D3DClass::Initialize(int screenWidth, int screenHeight, bool vsync, HWND hwnd, bool fullscreen, 
			  float screenDepth, float screenNear)
{
	HRESULT result;
	IDXGIFactory* factory;
	IDXGIAdapter* adapter;
	IDXGIOutput* adapterOutput;
	unsigned int numModes, i, numerator, denominator;
	DXGI_MODE_DESC* displayModeList;
	DXGI_SWAP_CHAIN_DESC swapChainDesc;
	D3D_FEATURE_LEVEL featureLevel;
	ID3D11Texture2D* backBufferPtr;
	D3D11_TEXTURE2D_DESC depthBufferDesc;
	D3D11_DEPTH_STENCIL_DESC depthStencilDesc;
	D3D11_DEPTH_STENCIL_VIEW_DESC depthStencilViewDesc;
	D3D11_RASTERIZER_DESC rasterDesc;
	D3D11_VIEWPORT viewport;
	float fieldOfView, screenAspect;
	D3D11_DEPTH_STENCIL_DESC depthDisabledStencilDesc;

我们有一个新的描述变量，用于设置两个新的混合状态。

	D3D11_BLEND_DESC blendStateDescription;


	// Store the vsync setting.
	m_vsync_enabled = vsync;

	// Create a DirectX graphics interface factory.
	result = CreateDXGIFactory(__uuidof(IDXGIFactory), (void**)&factory);
	if(FAILED(result))
	{
		return false;
	}

	// Use the factory to create an adapter for the primary graphics interface (video card).
	result = factory->EnumAdapters(0, &adapter);
	if(FAILED(result))
	{
		return false;
	}

	// Enumerate the primary adapter output (monitor).
	result = adapter->EnumOutputs(0, &adapterOutput);
	if(FAILED(result))
	{
		return false;
	}

	// Get the number of modes that fit the DXGI_FORMAT_R8G8B8A8_UNORM display format for the adapter output (monitor).
	result = adapterOutput->GetDisplayModeList(DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_ENUM_MODES_INTERLACED, &numModes, NULL);
	if(FAILED(result))
	{
		return false;
	}

	// Create a list to hold all the possible display modes for this monitor/video card combination.
	displayModeList = new DXGI_MODE_DESC[numModes];
	if(!displayModeList)
	{
		return false;
	}

	// Now fill the display mode list structures.
	result = adapterOutput->GetDisplayModeList(DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_ENUM_MODES_INTERLACED, &numModes, displayModeList);
	if(FAILED(result))
	{
		return false;
	}

	// Now go through all the display modes and find the one that matches the screen width and height.
	// When a match is found store the numerator and denominator of the refresh rate for that monitor.
	for(i=0; i<numModes; i++)
	{
		if(displayModeList[i].Width == (unsigned int)screenWidth)
		{
			if(displayModeList[i].Height == (unsigned int)screenHeight)
			{
				numerator = displayModeList[i].RefreshRate.Numerator;
				denominator = displayModeList[i].RefreshRate.Denominator;
			}
		}
	}

	// Release the display mode list.
	delete [] displayModeList;
	displayModeList = 0;

	// Release the adapter output.
	adapterOutput->Release();
	adapterOutput = 0;

	// Release the adapter.
	adapter->Release();
	adapter = 0;

	// Release the factory.
	factory->Release();
	factory = 0;

	// Initialize the swap chain description.
	ZeroMemory(&swapChainDesc, sizeof(swapChainDesc));

	// Set to a single back buffer.
	swapChainDesc.BufferCount = 1;

	// Set the width and height of the back buffer.
	swapChainDesc.BufferDesc.Width = screenWidth;
	swapChainDesc.BufferDesc.Height = screenHeight;

	// Set regular 32-bit surface for the back buffer.
	swapChainDesc.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;

	// Set the refresh rate of the back buffer.
	if(m_vsync_enabled)
	{
		swapChainDesc.BufferDesc.RefreshRate.Numerator = numerator;
		swapChainDesc.BufferDesc.RefreshRate.Denominator = denominator;
	}
	else
	{
		swapChainDesc.BufferDesc.RefreshRate.Numerator = 0;
		swapChainDesc.BufferDesc.RefreshRate.Denominator = 1;
	}

	// Set the usage of the back buffer.
	swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;

	// Set the handle for the window to render to.
	swapChainDesc.OutputWindow = hwnd;

	// Turn multisampling off.
	swapChainDesc.SampleDesc.Count = 1;
	swapChainDesc.SampleDesc.Quality = 0;

	// Set to full screen or windowed mode.
	if(fullscreen)
	{
		swapChainDesc.Windowed = false;
	}
	else
	{
		swapChainDesc.Windowed = true;
	}

	// Set the scan line ordering and scaling to unspecified.
	swapChainDesc.BufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;
	swapChainDesc.BufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;

	// Discard the back buffer contents after presenting.
	swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;

	// Don't set the advanced flags.
	swapChainDesc.Flags = 0;

	// Set the feature level to DirectX 11.
	featureLevel = D3D_FEATURE_LEVEL_11_0;

	// Create the swap chain, Direct3D device, and Direct3D device context.
	result = D3D11CreateDeviceAndSwapChain(NULL, D3D_DRIVER_TYPE_HARDWARE, NULL, 0, &featureLevel, 1, 
					       D3D11_SDK_VERSION, &swapChainDesc, &m_swapChain, &m_device, NULL, &m_deviceContext);
	if(FAILED(result))
	{
		return false;
	}

	// Get the pointer to the back buffer.
	result = m_swapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&backBufferPtr);
	if(FAILED(result))
	{
		return false;
	}

	// Create the render target view with the back buffer pointer.
	result = m_device->CreateRenderTargetView(backBufferPtr, NULL, &m_renderTargetView);
	if(FAILED(result))
	{
		return false;
	}

	// Release pointer to the back buffer as we no longer need it.
	backBufferPtr->Release();
	backBufferPtr = 0;

	// Initialize the description of the depth buffer.
	ZeroMemory(&depthBufferDesc, sizeof(depthBufferDesc));

	// Set up the description of the depth buffer.
	depthBufferDesc.Width = screenWidth;
	depthBufferDesc.Height = screenHeight;
	depthBufferDesc.MipLevels = 1;
	depthBufferDesc.ArraySize = 1;
	depthBufferDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
	depthBufferDesc.SampleDesc.Count = 1;
	depthBufferDesc.SampleDesc.Quality = 0;
	depthBufferDesc.Usage = D3D11_USAGE_DEFAULT;
	depthBufferDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
	depthBufferDesc.CPUAccessFlags = 0;
	depthBufferDesc.MiscFlags = 0;

	// Create the texture for the depth buffer using the filled out description.
	result = m_device->CreateTexture2D(&depthBufferDesc, NULL, &m_depthStencilBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Initialize the description of the stencil state.
	ZeroMemory(&depthStencilDesc, sizeof(depthStencilDesc));

	// Set up the description of the stencil state.
	depthStencilDesc.DepthEnable = true;
	depthStencilDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
	depthStencilDesc.DepthFunc = D3D11_COMPARISON_LESS;

	depthStencilDesc.StencilEnable = true;
	depthStencilDesc.StencilReadMask = 0xFF;
	depthStencilDesc.StencilWriteMask = 0xFF;

	// Stencil operations if pixel is front-facing.
	depthStencilDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
	depthStencilDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

	// Stencil operations if pixel is back-facing.
	depthStencilDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
	depthStencilDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

	// Create the depth stencil state.
	result = m_device->CreateDepthStencilState(&depthStencilDesc, &m_depthStencilState);
	if(FAILED(result))
	{
		return false;
	}

	// Set the depth stencil state.
	m_deviceContext->OMSetDepthStencilState(m_depthStencilState, 1);

	// Initialize the depth stencil view.
	ZeroMemory(&depthStencilViewDesc, sizeof(depthStencilViewDesc));

	// Set up the depth stencil view description.
	depthStencilViewDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
	depthStencilViewDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
	depthStencilViewDesc.Texture2D.MipSlice = 0;

	// Create the depth stencil view.
	result = m_device->CreateDepthStencilView(m_depthStencilBuffer, &depthStencilViewDesc, &m_depthStencilView);
	if(FAILED(result))
	{
		return false;
	}

	// Bind the render target view and depth stencil buffer to the output render pipeline.
	m_deviceContext->OMSetRenderTargets(1, &m_renderTargetView, m_depthStencilView);

	// Setup the raster description which will determine how and what polygons will be drawn.
	rasterDesc.AntialiasedLineEnable = false;
	rasterDesc.CullMode = D3D11_CULL_BACK;
	rasterDesc.DepthBias = 0;
	rasterDesc.DepthBiasClamp = 0.0f;
	rasterDesc.DepthClipEnable = true;
	rasterDesc.FillMode = D3D11_FILL_SOLID;
	rasterDesc.FrontCounterClockwise = false;
	rasterDesc.MultisampleEnable = false;
	rasterDesc.ScissorEnable = false;
	rasterDesc.SlopeScaledDepthBias = 0.0f;

	// Create the rasterizer state from the description we just filled out.
	result = m_device->CreateRasterizerState(&rasterDesc, &m_rasterState);
	if(FAILED(result))
	{
		return false;
	}

	// Now set the rasterizer state.
	m_deviceContext->RSSetState(m_rasterState);
	
	// Setup the viewport for rendering.
	viewport.Width = (float)screenWidth;
	viewport.Height = (float)screenHeight;
	viewport.MinDepth = 0.0f;
	viewport.MaxDepth = 1.0f;
	viewport.TopLeftX = 0.0f;
	viewport.TopLeftY = 0.0f;

	// Create the viewport.
	m_deviceContext->RSSetViewports(1, &viewport);

	// Setup the projection matrix.
	fieldOfView = (float)D3DX_PI / 4.0f;
	screenAspect = (float)screenWidth / (float)screenHeight;

	// Create the projection matrix for 3D rendering.
	D3DXMatrixPerspectiveFovLH(&m_projectionMatrix, fieldOfView, screenAspect, screenNear, screenDepth);

	// Initialize the world matrix to the identity matrix.
	D3DXMatrixIdentity(&m_worldMatrix);

	// Create an orthographic projection matrix for 2D rendering.
	D3DXMatrixOrthoLH(&m_orthoMatrix, (float)screenWidth, (float)screenHeight, screenNear, screenDepth);

	// Clear the second depth stencil state before setting the parameters.
	ZeroMemory(&depthDisabledStencilDesc, sizeof(depthDisabledStencilDesc));

	// Now create a second depth stencil state which turns off the Z buffer for 2D rendering.  The only difference is 
	// that DepthEnable is set to false, all other parameters are the same as the other depth stencil state.
	depthDisabledStencilDesc.DepthEnable = false;
	depthDisabledStencilDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
	depthDisabledStencilDesc.DepthFunc = D3D11_COMPARISON_LESS;
	depthDisabledStencilDesc.StencilEnable = true;
	depthDisabledStencilDesc.StencilReadMask = 0xFF;
	depthDisabledStencilDesc.StencilWriteMask = 0xFF;
	depthDisabledStencilDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
	depthDisabledStencilDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;
	depthDisabledStencilDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
	depthDisabledStencilDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

	// Create the state using the device.
	result = m_device->CreateDepthStencilState(&depthDisabledStencilDesc, &m_depthDisabledStencilState);
	if(FAILED(result))
	{
		return false;
	}

首先初始化混合状态描述。

	// Clear the blend state description.
	ZeroMemory(&blendStateDescription, sizeof(D3D11_BLEND_DESC));

要创建一个启用 alpha 的混合状态描述，请将 BlendEnable 更改为 TRUE，并将 DestBlend 更改为 D3D11_BLEND_INV_SRC_ALPHA。其他设置设置为其默认值，可以在 Windows DirectX 图形文档中查找。

	// Create an alpha enabled blend state description.
	blendStateDescription.RenderTarget[0].BlendEnable = TRUE;
	blendStateDescription.RenderTarget[0].SrcBlend = D3D11_BLEND_ONE;
	blendStateDescription.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA;
	blendStateDescription.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD;
	blendStateDescription.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ONE;
	blendStateDescription.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ZERO;
	blendStateDescription.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;
	blendStateDescription.RenderTarget[0].RenderTargetWriteMask = 0x0f;

然后，我们使用刚刚设置的描述创建一个启用 alpha 的混合状态。

	// Create the blend state using the description.
	result = m_device->CreateBlendState(&blendStateDescription, &m_alphaEnableBlendingState);
	if(FAILED(result))
	{
		return false;
	}

现在，要创建一个禁用 alpha 的状态，我们将刚刚更改的描述更改为将 BlendEnable 设置为 FALSE。其余设置可以保持原样。

	// Modify the description to create an alpha disabled blend state description.
	blendStateDescription.RenderTarget[0].BlendEnable = FALSE;

然后，我们使用修改后的混合状态描述创建一个禁用 alpha 的混合状态。现在，我们有两种混合状态，可以在它们之间切换以打开和关闭 alpha 混合。

	// Create the blend state using the description.
	result = m_device->CreateBlendState(&blendStateDescription, &m_alphaDisableBlendingState);
	if(FAILED(result))
	{
		return false;
	}

	return true;
}


void D3DClass::Shutdown()
{
	// Before shutting down set to windowed mode or when you release the swap chain it will throw an exception.
	if(m_swapChain)
	{
		m_swapChain->SetFullscreenState(false, NULL);
	}

释放两个新的混合状态。

	if(m_alphaEnableBlendingState)
	{
		m_alphaEnableBlendingState->Release();
		m_alphaEnableBlendingState = 0;
	}

	if(m_alphaDisableBlendingState)
	{
		m_alphaDisableBlendingState->Release();
		m_alphaDisableBlendingState = 0;
	}

	if(m_rasterState)
	{
		m_rasterState->Release();
		m_rasterState = 0;
	}

	if(m_depthStencilView)
	{
		m_depthStencilView->Release();
		m_depthStencilView = 0;
	}

	if(m_depthDisabledStencilState)
	{
		m_depthDisabledStencilState->Release();
		m_depthDisabledStencilState = 0;
	}

	if(m_depthStencilState)
	{
		m_depthStencilState->Release();
		m_depthStencilState = 0;
	}

	if(m_depthStencilBuffer)
	{
		m_depthStencilBuffer->Release();
		m_depthStencilBuffer = 0;
	}

	if(m_renderTargetView)
	{
		m_renderTargetView->Release();
		m_renderTargetView = 0;
	}

	if(m_deviceContext)
	{
		m_deviceContext->Release();
		m_deviceContext = 0;
	}

	if(m_device)
	{
		m_device->Release();
		m_device = 0;
	}

	if(m_swapChain)
	{
		m_swapChain->Release();
		m_swapChain = 0;
	}

	return;
}

第一个新函数 TurnOnAlphaBlending 允许我们使用我们的 m_alphaEnableBlendingState 混合状态与 OMSetBlendState 函数一起打开 alpha 混合。

void D3DClass::TurnOnAlphaBlending()
{
	float blendFactor[4];
	

	// Setup the blend factor.
	blendFactor[0] = 0.0f;
	blendFactor[1] = 0.0f;
	blendFactor[2] = 0.0f;
	blendFactor[3] = 0.0f;
	
	// Turn on the alpha blending.
	m_deviceContext->OMSetBlendState(m_alphaEnableBlendingState, blendFactor, 0xffffffff);

	return;
}

第二个新函数 TurnOffAlphaBlending 允许我们使用我们的 m_alphaDisableBlendingState 混合状态与 OMSetBlendState 函数一起关闭 alpha 混合。

void D3DClass::TurnOffAlphaBlending()
{
	float blendFactor[4];
	

	// Setup the blend factor.
	blendFactor[0] = 0.0f;
	blendFactor[1] = 0.0f;
	blendFactor[2] = 0.0f;
	blendFactor[3] = 0.0f;
	
	// Turn off the alpha blending.
	m_deviceContext->OMSetBlendState(m_alphaDisableBlendingState, blendFactor, 0xffffffff);

	return;
}

Graphicsclass.h

[编辑 | 编辑源代码]
////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _GRAPHICSCLASS_H_
#define _GRAPHICSCLASS_H_


/////////////
// GLOBALS //
/////////////
const bool FULL_SCREEN = true;
const bool VSYNC_ENABLED = true;
const float SCREEN_DEPTH = 1000.0f;
const float SCREEN_NEAR = 0.1f;


///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "d3dclass.h"
#include "cameraclass.h"

现在，我们包含了新的 TextClass 头文件。

#include "textclass.h"


////////////////////////////////////////////////////////////////////////////////
// Class name: GraphicsClass
////////////////////////////////////////////////////////////////////////////////
class GraphicsClass
{
public:
	GraphicsClass();
	GraphicsClass(const GraphicsClass&);
	~GraphicsClass();

	bool Initialize(int, int, HWND);
	void Shutdown();
	void Frame();
	bool Render();

private:
	D3DClass* m_D3D;
	CameraClass* m_Camera;

有一个用于 TextClass 对象的新私有变量。

	TextClass* m_Text;
};

#endif

Graphicsclass.cpp

[编辑 | 编辑源代码]

我们将只查看自上一教程以来已更改的函数。

////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "graphicsclass.h"


GraphicsClass::GraphicsClass()
{
	m_D3D = 0;
	m_Camera = 0;

在类构造函数中，将新的 TextClass 对象初始化为 null。

	m_Text = 0;
}


bool GraphicsClass::Initialize(int screenWidth, int screenHeight, HWND hwnd)
{
	bool result;
	D3DXMATRIX baseViewMatrix;

		
	// Create the Direct3D object.
	m_D3D = new D3DClass;
	if(!m_D3D)
	{
		return false;
	}

	// Initialize the Direct3D object.
	result = m_D3D->Initialize(screenWidth, screenHeight, VSYNC_ENABLED, hwnd, FULL_SCREEN, SCREEN_DEPTH, SCREEN_NEAR);
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize Direct3D", L"Error", MB_OK);
		return false;
	}

	// Create the camera object.
	m_Camera = new CameraClass;
	if(!m_Camera)
	{
		return false;
	}

我们从相机对象创建一个新的视图矩阵，供 TextClass 使用。它将始终使用此视图矩阵，以便文本始终绘制在屏幕上的相同位置。

	// Initialize a base view matrix with the camera for 2D user interface rendering.
	m_Camera->SetPosition(0.0f, 0.0f, -1.0f);
	m_Camera->Render();
	m_Camera->GetViewMatrix(baseViewMatrix);

在这里，我们创建并初始化新的 TextClass 对象。

	// Create the text object.
	m_Text = new TextClass;
	if(!m_Text)
	{
		return false;
	}

	// Initialize the text object.
	result = m_Text->Initialize(m_D3D->GetDevice(), m_D3D->GetDeviceContext(), hwnd, screenWidth, screenHeight, baseViewMatrix);
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the text object.", L"Error", MB_OK);
		return false;
	}

	return true;
}


void GraphicsClass::Shutdown()
{

在这里，我们释放 TextClass 对象。

	// Release the text object.
	if(m_Text)
	{
		m_Text->Shutdown();
		delete m_Text;
		m_Text = 0;
	}

	// Release the camera object.
	if(m_Camera)
	{
		delete m_Camera;
		m_Camera = 0;
	}

	// Release the D3D object.
	if(m_D3D)
	{
		m_D3D->Shutdown();
		delete m_D3D;
		m_D3D = 0;
	}

	return;
}


bool GraphicsClass::Render()
{
	D3DXMATRIX worldMatrix, viewMatrix, projectionMatrix, orthoMatrix;
	bool result;


	// Clear the buffers to begin the scene.
	m_D3D->BeginScene(0.0f, 0.0f, 0.0f, 1.0f);

	// Generate the view matrix based on the camera's position.
	m_Camera->Render();

	// Get the view, projection, and world matrices from the camera and D3D objects.
	m_Camera->GetViewMatrix(viewMatrix);
	m_D3D->GetWorldMatrix(worldMatrix);
	m_D3D->GetProjectionMatrix(projectionMatrix);
	m_D3D->GetOrthoMatrix(orthoMatrix);

	// Turn off the Z buffer to begin all 2D rendering.
	m_D3D->TurnZBufferOff();

在这里，我们打开 alpha 混合，以便文本可以与背景混合。

	// Turn on the alpha blending before rendering the text.
	m_D3D->TurnOnAlphaBlending();

我们在这里调用文本对象以将其所有句子渲染到屏幕上。就像 2D 图像一样，我们在绘制之前禁用 Z 缓冲区，并在所有 2D 绘制完成后再次启用它。

	// Render the text strings.
	result = m_Text->Render(m_D3D->GetDeviceContext(), worldMatrix, orthoMatrix);
	if(!result)
	{
		return false;
	}

在这里，我们关闭 alpha 混合，以便绘制的任何其他内容都不会与后面的对象进行 alpha 混合。

	// Turn off alpha blending after rendering the text.
	m_D3D->TurnOffAlphaBlending();

	// Turn the Z buffer back on now that all 2D rendering has completed.
	m_D3D->TurnZBufferOn();

	// Present the rendered scene to the screen.
	m_D3D->EndScene();

	return true;
}

总结

[编辑 | 编辑源代码]

现在，我们能够将彩色文本渲染到屏幕上的任何位置。

练习

[编辑 | 编辑源代码]

1. 重新编译代码，并确保您在屏幕上看到一个白色的 "Hello" 写在 100x100 处，以及一个黄色的 "Goodbye" 在其下方。

2. 更改句子的像素颜色、位置和内容。

3. 创建第三个句子结构并使其也进行渲染。

4. 在 GraphicsClass::Render 函数中注释掉混合调用，并将 m_D3D->BeginScene(0.0f, 0.0f, 1.0f, 1.0f); 设置在 GraphicsClass::Render 函数中。这将显示为什么需要混合。

5. 将混合调用添加回 GraphicsClass::Render 函数中，并保持 m_D3D->BeginScene(0.0f, 0.0f, 1.0f, 1.0f); 在 GraphicsClass::Render 函数中，以查看区别。

检索自 "https://wikibooks.cn/w/index.php?title=DirectX/10.0/Direct3D/Font_Engine&oldid=4109644"
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