DirectX 10 教程20:凹凸映射

原文地址:Tutorial 20: Bump Mapping(http://www.rastertek.com/dx10tut20.html)。

源代码下载:dx10tut20.zip

本教程介绍如何使用HLSL和C++实现凹凸映射,本教程的代码基于上一个教程。

我们使用的凹凸映射技术的正确叫法应是法线映射,原因是我们使用了一张叫做法线贴图的特殊纹理,通过法线贴图可以查询表面法线。法线贴图上的每个像素对应颜色纹理的每个像素的法线方向。我们使用的颜色纹理如下图所示:

颜色纹理

用于上一张纹理的法线贴图如下图所示:

法线贴图

使用法线映射之后,生成的效果如下图所示:

最终效果

如你所见,视觉效果变得更为真实。比起用更多的多边形,使用法线贴图能用小得多的开销达到同样的效果。

要创建法线贴图,通常需要别人生成一个3D模型,然后使用工具将这个3D模型表面转换为法线贴图。还有些工具可以将2D纹理处理成不错的法线贴图,但是没有从3D模型转换而来的那么精确。

创建法线贴图的工具会将x,y,z坐标转换为red,green,blue像素,分别代表三个矢量的方向,多边形的法线计算方法仍和以前相同,而切线和副法线的计算需要顶点和纹理坐标的信息。下图表示了三个矢量的方向:

三个矢量的方向

法线指向观察者,而切线和副法线位于多边形表面,切线沿x轴,副法线沿y轴,然后两者直接转换到法线贴图的tu和tv纹理坐标,其中纹理的U坐标映射切线,纹理V坐标映射副法线。

我们需要使用法线和纹理坐标事先计算切线和副法线矢量。注意不要在shader中进行这个操作,因为浮点计算是非常耗时的,我在加载模型的时候用C++代码编写了一个函数进行以上的工作。如果你需要在一个多边形数量很大的模型上施加凹凸映射,那么做好事先计算这三个矢量并将它们存储到你的模型格式中去。有了事先计算的切线和副法线,你就可以使用下面的方程确定任意像素的法线了。

bumpNormal = normal + bumpMap.x * tangent + bumpMap.y * binormal;

有了每个像素的法线,我们就可以进一步根据光照方向、颜色纹理确定最终的输出颜色。

框架

本教程使用的框架如下图所示,新的类为BumpMapShaderClass。

框架

首先看一下bump map HLSL shader代码:

Bumpmap.fx

////////////////////////////////////////////////////////////////////////////////
// Filename: bumpmap.fx
////////////////////////////////////////////////////////////////////////////////


/////////////
// GLOBALS //
/////////////
matrix worldMatrix;
matrix viewMatrix;
matrix projectionMatrix;

bump map shader需要两张纹理,数组中的第一张纹理为颜色纹理,第二张为法线贴图。

Texture2D shaderTextures[2];

需要光照方向和颜色用于光照计算。

float4 diffuseColor;
float3 lightDirection;


///////////////////
// SAMPLE STATES //
///////////////////
SamplerState SampleType
{
    Filter = MIN_MAG_MIP_LINEAR;
    AddressU = Wrap;
    AddressV = Wrap;
};

VertexInputType和PixelInputType都有了切线和副法线矢量用于法线映射的计算。

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

struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
   	float3 normal : NORMAL;
   	float3 tangent : TANGENT;
    float3 binormal : BINORMAL;
};


////////////////////////////////////////////////////////////////////////////////
// Vertex Shader
////////////////////////////////////////////////////////////////////////////////
PixelInputType BumpMapVertexShader(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;
    
	// Calculate the normal vector against the world matrix only and then normalize the final value.
	output.normal = mul(input.normal, (float3x3)worldMatrix);
	output.normal = normalize(output.normal);

输入的切线和副法线都会乘以世界矩阵并进行归一化。

	// Calculate the tangent vector against the world matrix only and then normalize the final value.
	output.tangent = mul(input.tangent, (float3x3)worldMatrix);
	output.tangent = normalize(output.tangent);

	// Calculate the binormal vector against the world matrix only and then normalize the final value.
    output.binormal = mul(input.binormal, (float3x3)worldMatrix);
	output.binormal = normalize(output.binormal);

	return output;
}

在像素着色器中,我们首先采样颜色纹理和法线贴图的像素,然后将法线贴图的值乘以2再减1使这个值的范围变为-1.0到+1.0,做这一步的原因是纹理坐标的范围是0.0到+1.0,只是法线值的一半,所以需要进行映射。之后,我们就使用前面提到的方程计算映射法线,经过归一化后的法线与光照方向进行点乘后就得出了光照强度,最后使用这个光照强度、光照颜色和纹理颜色获取最终的像素颜色。

////////////////////////////////////////////////////////////////////////////////
// Pixel Shader
////////////////////////////////////////////////////////////////////////////////
float4 BumpMapPixelShader(PixelInputType input) : SV_Target
{
	float4 textureColor;
    float4 bumpMap;
    float3 bumpNormal;
	float3 lightDir;
	float lightIntensity;
	float4 color;


	// Sample the texture pixel at this location.
	textureColor = shaderTextures[0].Sample(SampleType, input.tex);
	
    // Sample the pixel in the bump map.
    bumpMap = shaderTextures[1].Sample(SampleType, input.tex);

    // Expand the range of the normal value from (0, +1) to (-1, +1).
    bumpMap = (bumpMap * 2.0f) - 1.0f;

    // Calculate the normal from the data in the bump map.
    bumpNormal = input.normal + bumpMap.x * input.tangent + bumpMap.y * input.binormal;
	
    // Normalize the resulting bump normal.
    bumpNormal = normalize(bumpNormal);

	// Invert the light direction for calculations.
	lightDir = -lightDirection;

	// Calculate the amount of light on this pixel based on the bump map normal value.
	lightIntensity = saturate(dot(bumpNormal, lightDir));

	// Determine the final diffuse color based on the diffuse color and the amount of light intensity.
	color = saturate(diffuseColor * lightIntensity);

	// Combine the final bump light color with the texture color.
	//color = color * textureColor;
	
	return color;
}


////////////////////////////////////////////////////////////////////////////////
// Technique
////////////////////////////////////////////////////////////////////////////////
technique10 BumpMapTechnique
{
    pass pass0
    {
        SetVertexShader(CompileShader(vs_4_0, BumpMapVertexShader()));
        SetPixelShader(CompileShader(ps_4_0, BumpMapPixelShader()));
        SetGeometryShader(NULL);
    }
}

Bumpmapshaderclass.h

BumpMapShaderClass只是上一个教程shader类的修改版本。

////////////////////////////////////////////////////////////////////////////////
// Filename: bumpmapshaderclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _BUMPMAPSHADERCLASS_H_
#define _BUMPMAPSHADERCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <d3d10.h>
#include <d3dx10.h>
#include <fstream>
using namespace std;


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

	bool Initialize(ID3D10Device*, HWND);
	void Shutdown();
	void Render(ID3D10Device*, int, D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D10ShaderResourceView**, D3DXVECTOR3, D3DXVECTOR4);

private:
	bool InitializeShader(ID3D10Device*, HWND, WCHAR*);
	void ShutdownShader();
	void OutputShaderErrorMessage(ID3D10Blob*, HWND, WCHAR*);

	void SetShaderParameters(D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D10ShaderResourceView**, D3DXVECTOR3, D3DXVECTOR4);
	void RenderShader(ID3D10Device*, int);

private:
	ID3D10Effect* m_effect;
	ID3D10EffectTechnique* m_technique;
	ID3D10InputLayout* m_layout;

	ID3D10EffectMatrixVariable* m_worldMatrixPtr;
	ID3D10EffectMatrixVariable* m_viewMatrixPtr;
	ID3D10EffectMatrixVariable* m_projectionMatrixPtr;

bump map shader需要指向纹理数组,光照方向和颜色的指针。

	ID3D10EffectShaderResourceVariable* m_textureArrayPtr;
	ID3D10EffectVectorVariable* lightDirectionPtr;
	ID3D10EffectVectorVariable* diffuseColorPtr;
};

#endif

Bumpmapshaderclass.cpp

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


BumpMapShaderClass::BumpMapShaderClass()
{
	m_effect = 0;
	m_technique = 0;
	m_layout = 0;

	m_worldMatrixPtr = 0;
	m_viewMatrixPtr = 0;
	m_projectionMatrixPtr = 0;

在构造函数中将纹理数组、光照方向和颜色初始化为null。

	m_textureArrayPtr = 0;
	lightDirectionPtr = 0;
	diffuseColorPtr = 0;
}


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


BumpMapShaderClass::~BumpMapShaderClass()
{
}

Initialize方法加载bump map HLSL文件。

bool BumpMapShaderClass::Initialize(ID3D10Device* device, HWND hwnd)
{
	bool result;


	// Initialize the shader that will be used to draw the triangles.
	result = InitializeShader(device, hwnd, L"../Engine/bumpmap.fx");
	if(!result)
	{
		return false;
	}

	return true;
}

Shutdown释放shader effect。

void BumpMapShaderClass::Shutdown()
{
	// Shutdown the shader effect.
	ShutdownShader();

	return;
}

Render中首先设置shader参数,然后使用bump map shader绘制模型。

void BumpMapShaderClass::Render(ID3D10Device* device, int indexCount, D3DXMATRIX worldMatrix, D3DXMATRIX viewMatrix, 
								D3DXMATRIX projectionMatrix, ID3D10ShaderResourceView** textureArray, D3DXVECTOR3 lightDirection, 
								D3DXVECTOR4 diffuseColor)
{
	// Set the shader parameters that it will use for rendering.
	SetShaderParameters(worldMatrix, viewMatrix, projectionMatrix, textureArray, lightDirection, diffuseColor);

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

	return;
}

InitializeShader创建bump map shader。

bool BumpMapShaderClass::InitializeShader(ID3D10Device* device, HWND hwnd, WCHAR* filename)
{
	HRESULT result;
	ID3D10Blob* errorMessage;

polygon layout现在包含五个元素,包含了切线和副法线。

	D3D10_INPUT_ELEMENT_DESC polygonLayout[5];
	unsigned int numElements;
    D3D10_PASS_DESC passDesc;


	// Initialize the error message.
	errorMessage = 0;

	// Load the shader in from the file.
	result = D3DX10CreateEffectFromFile(filename, NULL, NULL, "fx_4_0", D3D10_SHADER_ENABLE_STRICTNESS, 0, 
										device, NULL, NULL, &m_effect, &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, filename);
		}
		// If there was  nothing in the error message then it simply could not find the shader file itself.
		else
		{
			MessageBox(hwnd, filename, L"Missing Shader File", MB_OK);
		}

		return false;
	}

Technique名称修改为BumpMapTechnique。

	// Get a pointer to the technique inside the shader.
	m_technique = m_effect->GetTechniqueByName("BumpMapTechnique");
	if(!m_technique)
	{
		return false;
	}

	// Now setup the layout of the data that goes into the shader.
	// This setup needs to match the VertexType stucture 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 = D3D10_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 = D3D10_APPEND_ALIGNED_ELEMENT;
	polygonLayout[1].InputSlotClass = D3D10_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 = D3D10_APPEND_ALIGNED_ELEMENT;
	polygonLayout[2].InputSlotClass = D3D10_INPUT_PER_VERTEX_DATA;
	polygonLayout[2].InstanceDataStepRate = 0;

layout现在包含了切线和副法线元素,除了语义名称,它们的定义方式与法线相同。

	polygonLayout[3].SemanticName = "TANGENT";
	polygonLayout[3].SemanticIndex = 0;
	polygonLayout[3].Format = DXGI_FORMAT_R32G32B32_FLOAT;
	polygonLayout[3].InputSlot = 0;
	polygonLayout[3].AlignedByteOffset = D3D10_APPEND_ALIGNED_ELEMENT;
	polygonLayout[3].InputSlotClass = D3D10_INPUT_PER_VERTEX_DATA;
	polygonLayout[3].InstanceDataStepRate = 0;

	polygonLayout[4].SemanticName = "BINORMAL";
	polygonLayout[4].SemanticIndex = 0;
	polygonLayout[4].Format = DXGI_FORMAT_R32G32B32_FLOAT;
	polygonLayout[4].InputSlot = 0;
	polygonLayout[4].AlignedByteOffset = D3D10_APPEND_ALIGNED_ELEMENT;
	polygonLayout[4].InputSlotClass = D3D10_INPUT_PER_VERTEX_DATA;
	polygonLayout[4].InstanceDataStepRate = 0;

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

	// Get the description of the first pass described in the shader technique.
    m_technique->GetPassByIndex(0)->GetDesc(&passDesc);

	// Create the input layout.
    result = device->CreateInputLayout(polygonLayout, numElements, passDesc.pIAInputSignature, passDesc.IAInputSignatureSize, 
									   &m_layout);
	if(FAILED(result))
	{
		return false;
	}

	// Get pointers to the three matrices inside the shader so we can update them from this class.
    m_worldMatrixPtr = m_effect->GetVariableByName("worldMatrix")->AsMatrix();
	m_viewMatrixPtr = m_effect->GetVariableByName("viewMatrix")->AsMatrix();
    m_projectionMatrixPtr = m_effect->GetVariableByName("projectionMatrix")->AsMatrix();

下面的代码获取纹理数组,光线方向,光线颜色的指针。

	// Get pointer to the texture array resource inside the shader.
	m_textureArrayPtr = m_effect->GetVariableByName("shaderTextures")->AsShaderResource();

	// Get a pointer to the light direction and color variables inside the shader.
	lightDirectionPtr = m_effect->GetVariableByName("lightDirection")->AsVector();
	diffuseColorPtr = m_effect->GetVariableByName("diffuseColor")->AsVector();

	return true;
}

ShutdownShader方法释放所有在InitializeShader方法中创建的对象。

void BumpMapShaderClass::ShutdownShader()
{
	// Release the light pointers.
	lightDirectionPtr = 0;
	diffuseColorPtr = 0;

	// Release the pointer to the texture array in the shader file.
	m_textureArrayPtr = 0;

	// Release the pointers to the matrices inside the shader.
	m_worldMatrixPtr = 0;
	m_viewMatrixPtr = 0;
	m_projectionMatrixPtr = 0;

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

	// Release the pointer to the shader technique.
	m_technique = 0;

	// Release the pointer to the shader.
	if(m_effect)
	{
		m_effect->Release();
		m_effect = 0;
	}

	return;
}


void BumpMapShaderClass::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 << compileErrors[i];
	}

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

	// Release the error message.
	errorMessage->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方法设置shader参数。

void BumpMapShaderClass::SetShaderParameters(D3DXMATRIX worldMatrix, D3DXMATRIX viewMatrix, D3DXMATRIX projectionMatrix, 
											 ID3D10ShaderResourceView** textureArray, D3DXVECTOR3 lightDirection, 
											 D3DXVECTOR4 diffuseColor)
{
	// Set the world matrix variable inside the shader.
    m_worldMatrixPtr->SetMatrix((float*)&worldMatrix);

	// Set the view matrix variable inside the shader.
	m_viewMatrixPtr->SetMatrix((float*)&viewMatrix);

	// Set the projection matrix variable inside the shader.
    m_projectionMatrixPtr->SetMatrix((float*)&projectionMatrix);

下面的代码设置纹理数组,此数组包含两张纹理,第一张为颜色纹理,第二张为法线贴图。

	// Bind the texture array.
	m_textureArrayPtr->SetResourceArray(textureArray, 0, 2);

下面的代码设置光照方向和颜色。

	// Set the direction of the light.
	lightDirectionPtr->SetFloatVector((float*)&lightDirection);

	// Set the diffuse color of the light.
    diffuseColorPtr->SetFloatVector((float*)&diffuseColor);

	return;
}

RenderShader方法使用bump map shader绘制模型。

void BumpMapShaderClass::RenderShader(ID3D10Device* device, int indexCount)
{
    D3D10_TECHNIQUE_DESC techniqueDesc;
	unsigned int i;
	

	// Set the input layout.
	device->IASetInputLayout(m_layout);

	// Get the description structure of the technique from inside the shader so it can be used for rendering.
    m_technique->GetDesc(&techniqueDesc);

    // Go through each pass in the technique (should be just one currently) and render the triangles.
	for(i=0; i<techniqueDesc.Passes; ++i)
    {
        m_technique->GetPassByIndex(i)->Apply(0);
        device->DrawIndexed(indexCount, 0, 0);
    }

	return;
}

Modelclass.h

////////////////////////////////////////////////////////////////////////////////
#ifndef _MODELCLASS_H_
#define _MODELCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <fstream>
using namespace std;


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


////////////////////////////////////////////////////////////////////////////////
// Class name: ModelClass
////////////////////////////////////////////////////////////////////////////////
class ModelClass
{
private:

VertexType结构体新添了切线和副法线矢量。

	struct VertexType
	{
		D3DXVECTOR3 position;
	    D3DXVECTOR2 texture;
		D3DXVECTOR3 normal;
		D3DXVECTOR3 tangent;
		D3DXVECTOR3 binormal;
	};

ModelType结构体也新添了切线和副法线矢量。

	struct ModelType
	{
		float x, y, z;
		float tu, tv;
		float nx, ny, nz;
		float tx, ty, tz;
		float bx, by, bz;
	};

下面两个结构体用于计算切线和副法线。

	struct TempVertexType
	{
		float x, y, z;
		float tu, tv;
		float nx, ny, nz;
	};

	struct VectorType
	{
		float x, y, z;
	};

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

	bool Initialize(ID3D10Device*, char*, WCHAR*, WCHAR*);
	void Shutdown();
	void Render(ID3D10Device*);

	int GetIndexCount();
	ID3D10ShaderResourceView** GetTextureArray();

private:
	bool InitializeBuffers(ID3D10Device*);
	void ShutdownBuffers();
	void RenderBuffers(ID3D10Device*);

	bool LoadTextures(ID3D10Device*, WCHAR*, WCHAR*);
	void ReleaseTextures();

	bool LoadModel(char*);
	void ReleaseModel();

新添了三个法线用于计算切线和副法线。

	void CalculateModelVectors();
	void CalculateTangentBinormal(TempVertexType, TempVertexType, TempVertexType, VectorType&, VectorType&);
	void CalculateNormal(VectorType, VectorType, VectorType&);

private:
	ID3D10Buffer *m_vertexBuffer, *m_indexBuffer;
	int m_vertexCount, m_indexCount;
	ModelType* m_model;
	TextureArrayClass* m_TextureArray;
};

#endif

Modelclass.cpp

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

Initialize方法的参数包含两张纹理的文件名称。

bool ModelClass::Initialize(ID3D10Device* device, char* modelFilename, WCHAR* textureFilename1, WCHAR* textureFilename2)
{
	bool result;


	// Load in the model data.
	result = LoadModel(modelFilename);
	if(!result)
	{
		return false;
	}

调用新的CalculateModelVectors方法计算切线和副法线,还要重新计算法线矢量。

	// Calculate the normal, tangent, and binormal vectors for the model.
	CalculateModelVectors();

	// Initialize the vertex and index buffer that hold the geometry for the triangle.
	result = InitializeBuffers(device);
	if(!result)
	{
		return false;
	}

加载两张纹理。

	// Load the texture array for this model.
	result = LoadTextures(device, textureFilename1, textureFilename2);
	if(!result)
	{
		return false;
	}

	return true;
}

bool ModelClass::InitializeBuffers(ID3D10Device* device)
{
	VertexType* vertices;
	unsigned long* indices;
	D3D10_BUFFER_DESC vertexBufferDesc, indexBufferDesc;
    D3D10_SUBRESOURCE_DATA vertexData, indexData;
	HRESULT result;
	int i;

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

	// Create the index array.
	indices = new unsigned long[m_indexCount];
	if(!indices)
	{
		return false;
	}

InitializeBuffers有所改变,顶点数组加载的数据来自于ModelType数组,而ModelType数组现在包含了切线和副法线数据,它们需要复制到顶点数组。

	// Load the vertex array and index array with data.
	for(i=0; i<m_vertexCount; i++)
	{
		vertices[i].position = D3DXVECTOR3(m_model[i].x, m_model[i].y, m_model[i].z);
		vertices[i].texture = D3DXVECTOR2(m_model[i].tu, m_model[i].tv);
		vertices[i].normal = D3DXVECTOR3(m_model[i].nx, m_model[i].ny, m_model[i].nz);
		vertices[i].tangent = D3DXVECTOR3(m_model[i].tx, m_model[i].ty, m_model[i].tz);
		vertices[i].binormal = D3DXVECTOR3(m_model[i].bx, m_model[i].by, m_model[i].bz);

		indices[i] = i;
	}

	// Set up the description of the vertex buffer.
    vertexBufferDesc.Usage = D3D10_USAGE_DEFAULT;
    vertexBufferDesc.ByteWidth = sizeof(VertexType) * m_vertexCount;
    vertexBufferDesc.BindFlags = D3D10_BIND_VERTEX_BUFFER;
    vertexBufferDesc.CPUAccessFlags = 0;
    vertexBufferDesc.MiscFlags = 0;

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

	// Now finally create the vertex buffer.
    result = device->CreateBuffer(&vertexBufferDesc, &vertexData, &m_vertexBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Set up the description of the index buffer.
    indexBufferDesc.Usage = D3D10_USAGE_DEFAULT;
    indexBufferDesc.ByteWidth = sizeof(unsigned long) * m_indexCount;
    indexBufferDesc.BindFlags = D3D10_BIND_INDEX_BUFFER;
    indexBufferDesc.CPUAccessFlags = 0;
    indexBufferDesc.MiscFlags = 0;

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

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

	// Release the arrays now that the vertex and index buffers have been created and loaded.
	delete [] vertices;
	vertices = 0;

	delete [] indices;
	indices = 0;

	return true;
}

LoadTextures加载颜色纹理和法线贴图。

bool ModelClass::LoadTextures(ID3D10Device* device, WCHAR* filename1, WCHAR* filename2)
{
	bool result;


	// Create the texture array object.
	m_TextureArray = new TextureArrayClass;
	if(!m_TextureArray)
	{
		return false;
	}

	// Initialize the texture array object.
	result = m_TextureArray->Initialize(device, filename1, filename2);
	if(!result)
	{
		return false;
	}

	return true;
}

CalculateModelVectors生成模型的切线和副法线,并且重新计算法线矢量。它首先计算模型有多少个面(三角形),然后根据每个三角形的三个顶点计算切线、副法线和法线。计算了这三个矢量之后将它们保存到ModelType结构数组中。

void ModelClass::CalculateModelVectors()
{
	int faceCount, i, index;
	TempVertexType vertex1, vertex2, vertex3;
	VectorType tangent, binormal, normal;


	// Calculate the number of faces in the model.
	faceCount = m_vertexCount / 3;

	// Initialize the index to the model data.
	index = 0;

	// Go through all the faces and calculate the the tangent, binormal, and normal vectors.
	for(i=0; i<faceCount; i++)
	{
		// Get the three vertices for this face from the model.
		vertex1.x = m_model[index].x;
		vertex1.y = m_model[index].y;
		vertex1.z = m_model[index].z;
		vertex1.tu = m_model[index].tu;
		vertex1.tv = m_model[index].tv;
		vertex1.nx = m_model[index].nx;
		vertex1.ny = m_model[index].ny;
		vertex1.nz = m_model[index].nz;
		index++;

		vertex2.x = m_model[index].x;
		vertex2.y = m_model[index].y;
		vertex2.z = m_model[index].z;
		vertex2.tu = m_model[index].tu;
		vertex2.tv = m_model[index].tv;
		vertex2.nx = m_model[index].nx;
		vertex2.ny = m_model[index].ny;
		vertex2.nz = m_model[index].nz;
		index++;

		vertex3.x = m_model[index].x;
		vertex3.y = m_model[index].y;
		vertex3.z = m_model[index].z;
		vertex3.tu = m_model[index].tu;
		vertex3.tv = m_model[index].tv;
		vertex3.nx = m_model[index].nx;
		vertex3.ny = m_model[index].ny;
		vertex3.nz = m_model[index].nz;
		index++;

		// Calculate the tangent and binormal of that face.
		CalculateTangentBinormal(vertex1, vertex2, vertex3, tangent, binormal);

		// Calculate the new normal using the tangent and binormal.
		CalculateNormal(tangent, binormal, normal);

		// Store the normal, tangent, and binormal for this face back in the model structure.
		m_model[index-1].nx = normal.x;
		m_model[index-1].ny = normal.y;
		m_model[index-1].nz = normal.z;
		m_model[index-1].tx = tangent.x;
		m_model[index-1].ty = tangent.y;
		m_model[index-1].tz = tangent.z;
		m_model[index-1].bx = binormal.x;
		m_model[index-1].by = binormal.y;
		m_model[index-1].bz = binormal.z;

		m_model[index-2].nx = normal.x;
		m_model[index-2].ny = normal.y;
		m_model[index-2].nz = normal.z;
		m_model[index-2].tx = tangent.x;
		m_model[index-2].ty = tangent.y;
		m_model[index-2].tz = tangent.z;
		m_model[index-2].bx = binormal.x;
		m_model[index-2].by = binormal.y;
		m_model[index-2].bz = binormal.z;

		m_model[index-3].nx = normal.x;
		m_model[index-3].ny = normal.y;
		m_model[index-3].nz = normal.z;
		m_model[index-3].tx = tangent.x;
		m_model[index-3].ty = tangent.y;
		m_model[index-3].tz = tangent.z;
		m_model[index-3].bx = binormal.x;
		m_model[index-3].by = binormal.y;
		m_model[index-3].bz = binormal.z;
	}

	return;
}

CalculateTangentBinormal方法的参数为三角形的三个顶点,经过计算后返回这三个顶点的切线和副法线。

void ModelClass::CalculateTangentBinormal(TempVertexType vertex1, TempVertexType vertex2, TempVertexType vertex3,
										  VectorType& tangent, VectorType& binormal)
{
	float vector1[3], vector2[3];
	float tuVector[2], tvVector[2];
	float den;
	float length;


	// Calculate the two vectors for this face.
	vector1[0] = vertex2.x - vertex1.x;
	vector1[1] = vertex2.y - vertex1.y;
	vector1[2] = vertex2.z - vertex1.z;

	vector2[0] = vertex3.x - vertex1.x;
	vector2[1] = vertex3.y - vertex1.y;
	vector2[2] = vertex3.z - vertex1.z;

	// Calculate the tu and tv texture space vectors.
	tuVector[0] = vertex2.tu - vertex1.tu;
	tvVector[0] = vertex2.tv - vertex1.tv;

	tuVector[1] = vertex3.tu - vertex1.tu;
	tvVector[1] = vertex3.tv - vertex1.tv;

	// Calculate the denominator of the tangent/binormal equation.
	den = 1.0f / (tuVector[0] * tvVector[1] - tuVector[1] * tvVector[0]);

	// Calculate the cross products and multiply by the coefficient to get the tangent and binormal.
	tangent.x = (tvVector[1] * vector1[0] - tvVector[0] * vector2[0]) * den;
	tangent.y = (tvVector[1] * vector1[1] - tvVector[0] * vector2[1]) * den;
	tangent.z = (tvVector[1] * vector1[2] - tvVector[0] * vector2[2]) * den;

	binormal.x = (tuVector[0] * vector2[0] - tuVector[1] * vector1[0]) * den;
	binormal.y = (tuVector[0] * vector2[1] - tuVector[1] * vector1[1]) * den;
	binormal.z = (tuVector[0] * vector2[2] - tuVector[1] * vector1[2]) * den;

	// Calculate the length of this normal.
	length = sqrt((tangent.x * tangent.x) + (tangent.y * tangent.y) + (tangent.z * tangent.z));
			
	// Normalize the normal and then store it
	tangent.x = tangent.x / length;
	tangent.y = tangent.y / length;
	tangent.z = tangent.z / length;

	// Calculate the length of this normal.
	length = sqrt((binormal.x * binormal.x) + (binormal.y * binormal.y) + (binormal.z * binormal.z));
			
	// Normalize the normal and then store it
	binormal.x = binormal.x / length;
	binormal.y = binormal.y / length;
	binormal.z = binormal.z / length;

	return;
}

CalculateNormal方法的参数为切线和副法线,经过叉乘计算获取法线矢量。

void ModelClass::CalculateNormal(VectorType tangent, VectorType binormal, VectorType& normal)
{
	float length;


	// Calculate the cross product of the tangent and binormal which will give the normal vector.
	normal.x = (tangent.y * binormal.z) - (tangent.z * binormal.y);
	normal.y = (tangent.z * binormal.x) - (tangent.x * binormal.z);
	normal.z = (tangent.x * binormal.y) - (tangent.y * binormal.x);

	// Calculate the length of the normal.
	length = sqrt((normal.x * normal.x) + (normal.y * normal.y) + (normal.z * normal.z));

	// Normalize the normal.
	normal.x = normal.x / length;
	normal.y = normal.y / length;
	normal.z = normal.z / length;

	return;
}

Graphicsclass.h

////////////////////////////////////////////////////////////////////////////////
// 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"
#include "modelclass.h"

新的BumpMapShaderClass头文件包含在GraphicsClass头文件中。

#include "bumpmapshaderclass.h"
#include "lightclass.h"


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

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

private:
	D3DClass* m_D3D;
	CameraClass* m_Camera;
	ModelClass* m_Model;

新添了BumpMapShaderClass对象。

	BumpMapShaderClass* m_BumpMapShader;
	LightClass* m_Light;
};

#endif

Graphicsclass.cpp

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


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

在构造函数中将BumpMapShaderClass对象初始化为null。

	m_BumpMapShader = 0;
	m_Light = 0;
}


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


GraphicsClass::~GraphicsClass()
{
}


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;
	}

	// 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);

	// Create the model object.
	m_Model = new ModelClass;
	if(!m_Model)
	{
		return false;
	}

ModelClass对象初始化为一个立方体,颜色纹理为stone01.dds,法线贴图为bump01.dds。

	// Initialize the model object.
	result = m_Model->Initialize(m_D3D->GetDevice(), "../Engine/data/cube.txt", L"../Engine/data/stone01.dds", 
								 L"../Engine/data/bump01.dds");
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the model object.", L"Error", MB_OK);
		return false;
	}

创建并初始化BumpMapShaderClass对象。

	// Create the bump map shader object.
	m_BumpMapShader = new BumpMapShaderClass;
	if(!m_BumpMapShader)
	{
		return false;
	}

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

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

光照颜色设置为白色,光照方向设置为正Z轴方向。

	// Initialize the light object.
	m_Light->SetDiffuseColor(1.0f, 1.0f, 1.0f, 1.0f);
	m_Light->SetDirection(0.0f, 0.0f, 1.0f);

	return true;
}


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

在Shutdown方法中释放BumpMapShaderClass对象。

	// Release the bump map shader object.
	if(m_BumpMapShader)
	{
		m_BumpMapShader->Shutdown();
		delete m_BumpMapShader;
		m_BumpMapShader = 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 Direct3D object.
	if(m_D3D)
	{
		m_D3D->Shutdown();
		delete m_D3D;
		m_D3D = 0;
	}

	return;
}


bool GraphicsClass::Frame()
{
	// Set the position of the camera.
	m_Camera->SetPosition(0.0f, 0.0f, -5.0f);

	return true;
}


bool GraphicsClass::Render()
{
	D3DXMATRIX worldMatrix, viewMatrix, projectionMatrix, orthoMatrix;
	static float rotation = 0.0f;


	// 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, projection, and ortho matrices from the camera and d3d objects.
	m_D3D->GetWorldMatrix(worldMatrix);
	m_Camera->GetViewMatrix(viewMatrix);
	m_D3D->GetProjectionMatrix(projectionMatrix);
	m_D3D->GetOrthoMatrix(orthoMatrix);

旋转立方体观察效果。

	// Update the rotation variable each frame.
	rotation += (float)D3DX_PI * 0.0025f;
	if(rotation > 360.0f)
	{
		rotation -= 360.0f;
	}

	// Rotate the world matrix by the rotation value.
	D3DXMatrixRotationY(&worldMatrix, rotation);

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

	// Render the model using the bump map shader.
	m_BumpMapShader->Render(m_D3D->GetDevice(), m_Model->GetIndexCount(), worldMatrix, viewMatrix, projectionMatrix, 
							m_Model->GetTextureArray(), m_Light->GetDirection(), m_Light->GetDiffuseColor());

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

	return true;
}

总结

使用bump map shader,你可以只用2D纹理就达到细节清晰的场景。

程序截图

练习

1.编译并运行程序,你会看到一个旋转的立方体,按escape键退出。

2.在像素着色器中注释color = color * textureColor;,看看只有凹凸光照的效果。

3.移动相机和光源位置,从不同角度观察效果。

文件下载(已下载 1113 次)

发布时间:2012/8/8 0:45:41  阅读次数:6672

2006 - 2024,推荐分辨率1024*768以上,推荐浏览器Chrome、Edge等现代浏览器,截止2021年12月5日的访问次数:1872万9823 站长邮箱

沪ICP备18037240号-1

沪公网安备 31011002002865号