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DirectX/10.0/Direct3D/镜面光照

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本教程将介绍如何在 DirectX 11 中使用 HLSL 实现镜面光照。本教程中的代码是在之前教程的代码基础上构建的。

镜面光照是使用明亮的点状高光来提供光源位置的视觉线索。例如，一个红色的球体只有环境光和漫反射光看起来是这样的

现在，如果我们添加一个白色的镜面高光，我们将得到以下结果

镜面光照最常用于为金属表面（如镜子和高度抛光/反射金属表面）提供光反射。它也用于其他材料，例如将阳光反射到水中。使用得当，它可以为大多数 3D 场景增添一定程度的逼真感。

镜面光照的方程式如下

	SpecularLighting = SpecularColor * (SpecularColorOfLight * ((NormalVector dot HalfWayVector) power SpecularReflectionPower) * Attentuation * Spotlight)

我们将修改方程式以产生最基本的镜面光照效果，如下所示

	SpecularLighting = SpecularLightColor * (ViewingDirection dot ReflectionVector) power SpecularReflectionPower

此方程式中的反射向量必须通过将光强度的两倍乘以顶点法线来生成。从光线方向减去，然后给出光源和视角之间的反射向量。

	ReflectionVector = 2 * LightIntensity * VertexNormal - LightDirection

方程式中的视角方向是通过从摄像机的位置减去顶点的位置来生成的。

	ViewingDirection = CameraPosition - VertexPosition

让我们看看修改后的光线着色器，看看它是如何实现的

Light.vs

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////////////////////////////////////////////////////////////////////////////////
// Filename: light.vs
////////////////////////////////////////////////////////////////////////////////


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

我们添加了一个新的常量缓冲区来保存摄像机信息。在这个着色器中，我们需要摄像机的位置来确定从哪里查看这个顶点，用于镜面计算。

cbuffer CameraBuffer
{
    float3 cameraPosition;
    float padding;
};
 

//////////////
// TYPEDEFS //
//////////////
struct VertexInputType
{
    float4 position : POSITION;
    float2 tex : TEXCOORD0;
    float3 normal : NORMAL;
};

PixelInputType 结构体进行了修改，因为视角方向需要在顶点着色器中计算，然后发送到像素着色器中进行镜面光照计算。

struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
    float3 normal : NORMAL;
    float3 viewDirection : TEXCOORD1;
};
 

////////////////////////////////////////////////////////////////////////////////
// Vertex Shader
////////////////////////////////////////////////////////////////////////////////
PixelInputType LightVertexShader(VertexInputType input)
{
    PixelInputType output;
    float4 worldPosition;
 

    // 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;
    
    // Calculate the normal vector against the world matrix only.
    output.normal = mul(input.normal, (float3x3)worldMatrix);
	
    // Normalize the normal vector.
    output.normal = normalize(output.normal);

视角方向在此处在顶点着色器中计算。我们计算顶点的世界位置，并从摄像机位置减去它以确定我们从哪里查看场景。最终值被归一化并发送到像素着色器。

    // Calculate the position of the vertex in the world.
    worldPosition = mul(input.position, worldMatrix);

    // Determine the viewing direction based on the position of the camera and the position of the vertex in the world.
    output.viewDirection = cameraPosition.xyz - worldPosition.xyz;
	
    // Normalize the viewing direction vector.
    output.viewDirection = normalize(output.viewDirection);
 
    return output;
}

Light.ps

[edit | edit source]
////////////////////////////////////////////////////////////////////////////////
// Filename: light.ps
////////////////////////////////////////////////////////////////////////////////


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

光线缓冲区已更新，包含 specularColor 和 specularPower 值，用于镜面光照计算。

cbuffer LightBuffer
{
    float4 ambientColor;
    float4 diffuseColor;
    float3 lightDirection;
    float specularPower;
    float4 specularColor;
};
 

//////////////
// TYPEDEFS //
//////////////

PixelInputType 结构体在此处也进行了修改，以反映顶点着色器中的更改。

struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
    float3 normal : NORMAL;
    float3 viewDirection : TEXCOORD1;
};
 

////////////////////////////////////////////////////////////////////////////////
// Pixel Shader
////////////////////////////////////////////////////////////////////////////////
float4 LightPixelShader(PixelInputType input) : SV_TARGET
{
    float4 textureColor;
    float3 lightDir;
    float lightIntensity;
    float4 color;
    float3 reflection;
    float4 specular;
 

    // Sample the pixel color from the texture using the sampler at this texture coordinate location.
    textureColor = shaderTexture.Sample(SampleType, input.tex);

    // Set the default output color to the ambient light value for all pixels.
    color = ambientColor;
    // Initialize the specular color.
    specular = float4(0.0f, 0.0f, 0.0f, 0.0f);
 
    // Invert the light direction for calculations.
    lightDir = -lightDirection;

    // Calculate the amount of light on this pixel.
    lightIntensity = saturate(dot(input.normal, lightDir));

    if(lightIntensity > 0.0f)
    {
        // Determine the final diffuse color based on the diffuse color and the amount of light intensity.
        color += (diffuseColor * lightIntensity);
        // Saturate the ambient and diffuse color.
        color = saturate(color);

镜面光照的反射向量在此处在像素着色器中计算，前提是光强大于零。这与教程开头列出的方程式相同。

        // Calculate the reflection vector based on the light intensity, normal vector, and light direction.
        reflection = normalize(2 * lightIntensity * input.normal - lightDir);

然后使用反射向量和视角方向计算镜面光的数量。观察者和光源之间的角度越小，镜面光反射就越大。结果被取到 specularPower 值的幂。specularPower 值越低，最终效果越大。

        // Determine the amount of specular light based on the reflection vector, viewing direction, and specular power.
        specular = pow(saturate(dot(reflection, input.viewDirection)), specularPower);
 
    }

    // Multiply the texture pixel and the input color to get the textured result.
    color = color * textureColor;

我们直到最后才添加镜面效果。它是一个高光，需要添加到最终值中，否则它将无法正常显示。

    // Add the specular component last to the output color.
    color = saturate(color + specular);
 
    return color;
}

Lightshaderclass.h

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LightShaderClass 已从之前的教程中修改，现在可以处理镜面光照。

////////////////////////////////////////////////////////////////////////////////
// Filename: lightshaderclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _LIGHTSHADERCLASS_H_
#define _LIGHTSHADERCLASS_H_


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


////////////////////////////////////////////////////////////////////////////////
// Class name: LightShaderClass
////////////////////////////////////////////////////////////////////////////////
class LightShaderClass
{
private:
	struct MatrixBufferType
	{
		D3DXMATRIX world;
		D3DXMATRIX view;
		D3DXMATRIX projection;
	};

我们添加了一个新的摄像机缓冲区结构体，以匹配顶点着色器中的新摄像机常量缓冲区。请注意，我们添加了一个填充以使结构体大小为 16 的倍数，以防止在使用 sizeof 时使用此结构体时 CreateBuffer 失败。

	struct CameraBufferType
	{
		D3DXVECTOR3 cameraPosition;
		float padding;
	};

LightBufferType 已修改为包含 specularColor 和 specularPower，以匹配像素着色器中的光线常量缓冲区。请注意，我将 specularPower 放在光线方向旁边以形成一个 4 个浮点数的槽，而不是使用填充，以便结构体可以保持为 16 字节的倍数。此外，如果 specularPower 放在结构体的最后，并且在光线方向下方没有使用填充，那么着色器将无法正常工作。这是因为即使结构体是 16 的倍数，每个槽本身在逻辑上也不是 16 字节对齐的。

	struct LightBufferType
	{
		D3DXVECTOR4 ambientColor;
		D3DXVECTOR4 diffuseColor;
		D3DXVECTOR3 lightDirection;
		float specularPower;
		D3DXVECTOR4 specularColor;
	};
 
public:
	LightShaderClass();
	LightShaderClass(const LightShaderClass&);
	~LightShaderClass();

	bool Initialize(ID3D11Device*, HWND);
	void Shutdown();
	bool Render(ID3D11DeviceContext*, int, D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D11ShaderResourceView*, D3DXVECTOR3, D3DXVECTOR4, D3DXVECTOR4, 
		    D3DXVECTOR3, D3DXVECTOR4, float);

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

	bool SetShaderParameters(ID3D11DeviceContext*, D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D11ShaderResourceView*, D3DXVECTOR3, D3DXVECTOR4, D3DXVECTOR4,
				 D3DXVECTOR3, D3DXVECTOR4, float);
	void RenderShader(ID3D11DeviceContext*, int);

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

我们在此添加了一个新的摄像机常量缓冲区，它将用于在顶点着色器中设置摄像机位置。

	ID3D11Buffer* m_cameraBuffer;
 
	ID3D11Buffer* m_lightBuffer;
};

#endif

Lightshaderclass.cpp

[edit | edit source]
////////////////////////////////////////////////////////////////////////////////
// Filename: lightshaderclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "lightshaderclass.h"


LightShaderClass::LightShaderClass()
{
	m_vertexShader = 0;
	m_pixelShader = 0;
	m_layout = 0;
	m_sampleState = 0;
	m_matrixBuffer = 0;

在类构造函数中将新的摄像机常量缓冲区初始化为 null。

	m_cameraBuffer = 0;
 
	m_lightBuffer = 0;
}


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


LightShaderClass::~LightShaderClass()
{
}


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


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

	return true;
}


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

	return;
}

Render 函数现在接受 cameraPosition、specularColor 和 specularPower 值，并将它们发送到 SetShaderParameters 函数中，使其在渲染发生之前在光线着色器中处于活动状态。

bool LightShaderClass::Render(ID3D11DeviceContext* deviceContext, int indexCount, D3DXMATRIX worldMatrix, D3DXMATRIX viewMatrix, 
			      D3DXMATRIX projectionMatrix, ID3D11ShaderResourceView* texture, D3DXVECTOR3 lightDirection, D3DXVECTOR4 ambientColor,
			      D3DXVECTOR4 diffuseColor, D3DXVECTOR3 cameraPosition, D3DXVECTOR4 specularColor, float specularPower)

{
	bool result;


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

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

	return true;
}


bool LightShaderClass::InitializeShader(ID3D11Device* device, HWND hwnd, WCHAR* vsFilename, WCHAR* psFilename)
{
	HRESULT result;
	ID3D10Blob* errorMessage;
	ID3D10Blob* vertexShaderBuffer;
	ID3D10Blob* pixelShaderBuffer;
	D3D11_INPUT_ELEMENT_DESC polygonLayout[3];
	unsigned int numElements;
	D3D11_SAMPLER_DESC samplerDesc;
	D3D11_BUFFER_DESC matrixBufferDesc;
	D3D11_BUFFER_DESC cameraBufferDesc;
 
	D3D11_BUFFER_DESC lightBufferDesc;


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

	// Compile the vertex shader code.
	result = D3DX11CompileFromFile(vsFilename, NULL, NULL, "LightVertexShader", "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;
	}

	// Compile the pixel shader code.
	result = D3DX11CompileFromFile(psFilename, NULL, NULL, "LightPixelShader", "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 pixel 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;

	polygonLayout[2].SemanticName = "NORMAL";
	polygonLayout[2].SemanticIndex = 0;
	polygonLayout[2].Format = DXGI_FORMAT_R32G32B32_FLOAT;
	polygonLayout[2].InputSlot = 0;
	polygonLayout[2].AlignedByteOffset = D3D11_APPEND_ALIGNED_ELEMENT;
	polygonLayout[2].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;
	polygonLayout[2].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;

	// 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;
	}

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

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

我们设置了新摄像机缓冲区的描述，然后使用该描述创建了一个缓冲区。这将允许我们与顶点着色器中的摄像机位置交互并设置它。

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

	// Create the camera constant buffer pointer so we can access the vertex shader constant buffer from within this class.
	result = device->CreateBuffer(&cameraBufferDesc, NULL, &m_cameraBuffer);
	if(FAILED(result))
	{
		return false;
	}
 
	// Setup the description of the light dynamic constant buffer that is in the pixel shader.
	// Note that ByteWidth always needs to be a multiple of 16 if using D3D11_BIND_CONSTANT_BUFFER or CreateBuffer will fail.
	lightBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	lightBufferDesc.ByteWidth = sizeof(LightBufferType);
	lightBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
	lightBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	lightBufferDesc.MiscFlags = 0;
	lightBufferDesc.StructureByteStride = 0;

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

	return true;
}


void LightShaderClass::ShutdownShader()
{
	// Release the light constant buffer.
	if(m_lightBuffer)
	{
		m_lightBuffer->Release();
		m_lightBuffer = 0;
	}

在 ShutdownShader 函数中释放新的摄像机常量缓冲区。

	// Release the camera constant buffer.
	if(m_cameraBuffer)
	{
		m_cameraBuffer->Release();
		m_cameraBuffer = 0;
	}
 
	// Release the matrix constant buffer.
	if(m_matrixBuffer)
	{
		m_matrixBuffer->Release();
		m_matrixBuffer = 0;
	}

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


void LightShaderClass::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 函数已修改为接受 cameraPosition、specularColor 和 specularPower 作为输入。

bool LightShaderClass::SetShaderParameters(ID3D11DeviceContext* deviceContext, D3DXMATRIX worldMatrix, D3DXMATRIX viewMatrix, 
					   D3DXMATRIX projectionMatrix, ID3D11ShaderResourceView* texture, D3DXVECTOR3 lightDirection, 
					   D3DXVECTOR4 ambientColor, D3DXVECTOR4 diffuseColor, D3DXVECTOR3 cameraPosition, D3DXVECTOR4 specularColor, 
					   float specularPower)
 
{
	HRESULT result;
	D3D11_MAPPED_SUBRESOURCE mappedResource;
	unsigned int bufferNumber;
	MatrixBufferType* dataPtr;
	LightBufferType* dataPtr2;
	CameraBufferType* dataPtr3;
 

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

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

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

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

	// Unlock the constant buffer.
	deviceContext->Unmap(m_matrixBuffer, 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_matrixBuffer);

在此，我们锁定摄像机缓冲区并在其中设置摄像机位置值。

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

	// Get a pointer to the data in the constant buffer.
	dataPtr3 = (CameraBufferType*)mappedResource.pData;

	// Copy the camera position into the constant buffer.
	dataPtr3->cameraPosition = cameraPosition;
	dataPtr3->padding = 0.0f;

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

请注意，我们在设置常量缓冲区之前将 bufferNumber 设置为 1 而不是 0。这是因为它是在顶点着色器中的第二个缓冲区（第一个是矩阵缓冲区）。

	// Set the position of the camera constant buffer in the vertex shader.
	bufferNumber = 1;

	// Now set the camera constant buffer in the vertex shader with the updated values.
	deviceContext->VSSetConstantBuffers(bufferNumber, 1, &m_cameraBuffer);
 
	
	// Set shader texture resource in the pixel shader.
	deviceContext->PSSetShaderResources(0, 1, &texture);

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

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

光线常量缓冲区现在设置 specularColor 和 specularPower，以便像素着色器可以执行镜面光照计算。

	// Copy the lighting variables into the light constant buffer.
	dataPtr2->ambientColor = ambientColor;
	dataPtr2->diffuseColor = diffuseColor;
	dataPtr2->lightDirection = lightDirection;
	dataPtr2->specularColor = specularColor;
	dataPtr2->specularPower = specularPower;
 
	
	// Unlock the light constant buffer.
	deviceContext->Unmap(m_lightBuffer, 0);

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

	// Finally set the light constant buffer in the pixel shader with the updated values.
	deviceContext->PSSetConstantBuffers(bufferNumber, 1, &m_lightBuffer);

	return true;
}


void LightShaderClass::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 this triangle.
	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 triangle.
	deviceContext->DrawIndexed(indexCount, 0, 0);

	return;
}

Lightclass.h

[edit | edit source]

LightClass 已针对本教程进行了修改，以包含镜面分量和镜面相关辅助函数。

////////////////////////////////////////////////////////////////////////////////
// Filename: lightclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _LIGHTCLASS_H_
#define _LIGHTCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <d3dx10math.h>


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

	void SetAmbientColor(float, float, float, float);
	void SetDiffuseColor(float, float, float, float);
	void SetDirection(float, float, float);
	void SetSpecularColor(float, float, float, float);
	void SetSpecularPower(float);
 
	D3DXVECTOR4 GetAmbientColor();
	D3DXVECTOR4 GetDiffuseColor();
	D3DXVECTOR3 GetDirection();
	D3DXVECTOR4 GetSpecularColor();
	float GetSpecularPower();
 
private:
	D3DXVECTOR4 m_ambientColor;
	D3DXVECTOR4 m_diffuseColor;
	D3DXVECTOR3 m_direction;
	D3DXVECTOR4 m_specularColor;
	float m_specularPower;
 
};

#endif

Lightclass.cpp

[edit | edit source]
////////////////////////////////////////////////////////////////////////////////
// Filename: lightclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "lightclass.h"


LightClass::LightClass()
{
}


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


LightClass::~LightClass()
{
}


void LightClass::SetAmbientColor(float red, float green, float blue, float alpha)
{
	m_ambientColor = D3DXVECTOR4(red, green, blue, alpha);
	return;
}


void LightClass::SetDiffuseColor(float red, float green, float blue, float alpha)
{
	m_diffuseColor = D3DXVECTOR4(red, green, blue, alpha);
	return;
}


void LightClass::SetDirection(float x, float y, float z)
{
	m_direction = D3DXVECTOR3(x, y, z);
	return;
}

void LightClass::SetSpecularColor(float red, float green, float blue, float alpha)
{
	m_specularColor = D3DXVECTOR4(red, green, blue, alpha);
	return;
}


void LightClass::SetSpecularPower(float power)
{
	m_specularPower = power;
	return;
}
 

D3DXVECTOR4 LightClass::GetAmbientColor()
{
	return m_ambientColor;
}


D3DXVECTOR4 LightClass::GetDiffuseColor()
{
	return m_diffuseColor;
}


D3DXVECTOR3 LightClass::GetDirection()
{
	return m_direction;
}

D3DXVECTOR4 LightClass::GetSpecularColor()
{
	return m_specularColor;
}


float LightClass::GetSpecularPower()
{
	return m_specularPower;
}

Graphicsclass.h

[edit | edit source]

GraphicsClass 的头文件在本教程中没有改变。

////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _GRAPHICSCLASS_H_
#define _GRAPHICSCLASS_H_


///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "d3dclass.h"
#include "cameraclass.h"
#include "modelclass.h"
#include "lightshaderclass.h"
#include "lightclass.h"


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


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

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

private:
	bool Render(float);

private:
	D3DClass* m_D3D;
	CameraClass* m_Camera;
	ModelClass* m_Model;
	LightShaderClass* m_LightShader;
	LightClass* m_Light;
};

#endif

Graphicsclass.cpp

[edit | edit source]
////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "graphicsclass.h"


GraphicsClass::GraphicsClass()
{
	m_D3D = 0;
	m_Camera = 0;
	m_Model = 0;
	m_LightShader = 0;
	m_Light = 0;
}


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


GraphicsClass::~GraphicsClass()
{
}


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


	// 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;
	}

	// Set the initial position of the camera.
	m_Camera->SetPosition(0.0f, 0.0f, -10.0f);
	
	// Create the model object.
	m_Model = new ModelClass;
	if(!m_Model)
	{
		return false;
	}

	// Initialize the model object.
	result = m_Model->Initialize(m_D3D->GetDevice(), "../Engine/data/cube.txt", L"../Engine/data/seafloor.dds");
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the model object.", L"Error", MB_OK);
		return false;
	}

	// Create the light shader object.
	m_LightShader = new LightShaderClass;
	if(!m_LightShader)
	{
		return false;
	}

	// Initialize the light shader object.
	result = m_LightShader->Initialize(m_D3D->GetDevice(), hwnd);
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the light shader object.", L"Error", MB_OK);
		return false;
	}

	// Create the light object.
	m_Light = new LightClass;
	if(!m_Light)
	{
		return false;
	}

在光线类对象中，我们现在设置 specularColor 和 specularPower。在本教程中，我们将 specularColor 设置为白色，并将 specularPower 设置为 32。请记住，specularPower 值越低，镜面效果就越大。

	// Initialize the light object.
	m_Light->SetAmbientColor(0.15f, 0.15f, 0.15f, 1.0f);
	m_Light->SetDiffuseColor(1.0f, 1.0f, 1.0f, 1.0f);
	m_Light->SetDirection(0.0f, 0.0f, 1.0f);
	m_Light->SetSpecularColor(1.0f, 1.0f, 1.0f, 1.0f);
	m_Light->SetSpecularPower(32.0f);
 
	return true;
}


void GraphicsClass::Shutdown()
{
	// Release the light object.
	if(m_Light)
	{
		delete m_Light;
		m_Light = 0;
	}

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

	// Release the model object.
	if(m_Model)
	{
		m_Model->Shutdown();
		delete m_Model;
		m_Model = 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::Frame()
{
	bool result;
	static float rotation = 0.0f;


	// Update the rotation variable each frame.
	rotation += (float)D3DX_PI * 0.005f;
	if(rotation > 360.0f)
	{
		rotation -= 360.0f;
	}
	
	// Render the graphics scene.
	result = Render(rotation);
	if(!result)
	{
		return false;
	}

	return true;
}


bool GraphicsClass::Render(float rotation)
{
	D3DXMATRIX worldMatrix, viewMatrix, projectionMatrix;
	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 world, view, and projection matrices from the camera and d3d objects.
	m_Camera->GetViewMatrix(viewMatrix);
	m_D3D->GetWorldMatrix(worldMatrix);
	m_D3D->GetProjectionMatrix(projectionMatrix);

	// Rotate the world matrix by the rotation value so that the triangle will spin.
	D3DXMatrixRotationY(&worldMatrix, rotation);

	// Put the model vertex and index buffers on the graphics pipeline to prepare them for drawing.
	m_Model->Render(m_D3D->GetDeviceContext());

光线着色器渲染函数现在接受摄像机位置、光线镜面颜色和光线镜面功率。

	// Render the model using the light shader.
	result = m_LightShader->Render(m_D3D->GetDeviceContext(), m_Model->GetIndexCount(), worldMatrix, viewMatrix, projectionMatrix, 
				       m_Model->GetTexture(), m_Light->GetDirection(), m_Light->GetAmbientColor(), m_Light->GetDiffuseColor(), 
				       m_Camera->GetPosition(), m_Light->GetSpecularColor(), m_Light->GetSpecularPower());
 
	if(!result)
	{
		return false;
	}

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

	return true;
}

总结

[edit | edit source]

随着镜面光照的添加，我们现在每次立方体表面均匀地面向摄像机视角方向时，都会得到一个明亮的白色闪光。

待办事项练习

[编辑 | 编辑源代码]

1. 重新编译并运行项目，确保你获得一个旋转的立方体，每次立方体面向摄像头时都会闪烁明亮的镜面高光。

2. 改变光源的方向，例如 m_Light->SetDirection(1.0f, 0.0f, 1.0f)，观察光源来自不同方向的效果。

3. 创建一个拥有红色纹理的 5000 多个面的球体模型，以重新创建教程顶部的球体图像。

取自 "https://wikibooks.cn/w/index.php?title=DirectX/10.0/Direct3D/Specular_Lighting&oldid=4109645"
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