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DirectX10 龙书笔记- 一个颜色立方体程序
这篇是作为学习笔记之用，详细代码在Introduction to 3D Game Programming with Directx10里面的扉页，有个网址 www.d3dcoder.net 里面可以下载
这个程序的效果是:
这个demo展示了基本的directx基本的渲染流程.
首先是渲染管线: 它的作用是根据虚拟摄像机视角生成2D图像的基本步骤.
主要是类为ColoredCubeApp
class ColoredCubeApp : public D3DApp
{
public:
ColoredCubeApp(HINSTANCE hInstance);
~ColoredCubeApp();
void initApp(); //初始化
void onResize(); //窗口大小变化时候调用
void updateScene(float dt); //每一帧调用,负责更新参数
void drawScene(); //每一帧调用,负责绘制
private:
void buildFX(); //着色器
void buildVertexLayouts(); //输入汇编器，构建图元
private:
Box mBox;
ID3D10Effect* mFX;
ID3D10EffectTechnique* mTech;
ID3D10InputLayout* mVertexLayout;
ID3D10EffectMatrixVariable* mfxWVPVar;
D3DXMATRIX mView;
D3DXMATRIX mProj;
D3DXMATRIX mWVP;
float mTheta;
float mPhi;
};
这个类中的initAPP()为初始化渲染做准备
void ColoredCubeApp::initApp()
{
D3DApp::initApp();
mBox.init(md3dDevice, 0.3f); //这个是所要创建立方体的初始化。 提供了顶点缓冲区，和索引缓冲区
buildFX(); //这个是顶点着色器、几何着色器、像素着色器的配置
buildVertexLayouts();//根据以上信息构建图元
}
下面看具体mBox.init是怎么初始化立方体的
void Box::init(ID3D10Device* device, float scale)
{
md3dDevice = device;
mNumVertices = 8;
mNumFaces = 12; // 2 per quad
// Create vertex buffer
Vertex vertices[] =
{
{D3DXVECTOR3(-1.0f, -1.0f, -1.0f), WHITE},
{D3DXVECTOR3(-1.0f, +1.0f, -1.0f), BLACK},
{D3DXVECTOR3(+1.0f, +1.0f, -1.0f), RED},
{D3DXVECTOR3(+1.0f, -1.0f, -1.0f), GREEN},
{D3DXVECTOR3(-1.0f, -1.0f, +1.0f), BLUE},
{D3DXVECTOR3(-1.0f, +1.0f, +1.0f), YELLOW},
{D3DXVECTOR3(+1.0f, +1.0f, +1.0f), CYAN},
{D3DXVECTOR3(+1.0f, -1.0f, +1.0f), MAGENTA},
};
// Scale the box.
for(DWORD i = 0; i < mNumVertices; ++i)
vertices[i].pos *= scale;
//顶点缓冲区
D3D10_BUFFER_DESC vbd;
vbd.Usage = D3D10_USAGE_IMMUTABLE;
vbd.ByteWidth = sizeof(Vertex) * mNumVertices;
vbd.BindFlags = D3D10_BIND_VERTEX_BUFFER;
vbd.CPUAccessFlags = 0;
vbd.MiscFlags = 0;
D3D10_SUBRESOURCE_DATA vinitData;
vinitData.pSysMem = vertices;
HR(md3dDevice->CreateBuffer(&vbd, &vinitData, &mVB));
// Create the index buffer
//索引缓冲区
DWORD indices[] = {
// front face
0, 1, 2,
0, 2, 3,
// back face
4, 6, 5,
4, 7, 6,
// left face
4, 5, 1,
4, 1, 0,
// right face
3, 2, 6,
3, 6, 7,
// top face
1, 5, 6,
1, 6, 2,
// bottom face
4, 0, 3,
4, 3, 7
};
D3D10_BUFFER_DESC ibd;
ibd.Usage = D3D10_USAGE_IMMUTABLE;
ibd.ByteWidth = sizeof(DWORD) * mNumFaces*3;
ibd.BindFlags = D3D10_BIND_INDEX_BUFFER;
ibd.CPUAccessFlags = 0;
ibd.MiscFlags = 0;
D3D10_SUBRESOURCE_DATA iinitData;
iinitData.pSysMem = indices;
HR(md3dDevice->CreateBuffer(&ibd, &iinitData, &mIB));
}
从以上可知，主要作用就是先构建所需要的不重复的点，然后构建一个立方体索引点(索引是为了节约资源，不必再重复构建点)。
下面看buildFX() 里面的内容
hr = D3DX10CreateEffectFromFile(L"color.fx", 0, 0,
"fx_4_0",shaderFlags, 0,md3dDevice,0, 0, &mFX, &compilationErrors,0);
主要为这一句。
其中color.fx 是一个文本文件
//=============================================================================
// color.fx by Frank Luna (C) 2008 All Rights Reserved.
//
// Transforms and colors geometry.
//=============================================================================
cbuffer cbPerObject
{
float4x4 gWVP;
};
void VS(float3 iPosL : POSITION,
float4 iColor : COLOR,
out float4 oPosH : SV_POSITION,
out float4 oColor : COLOR)
{
// Transform to homogeneous clip space.
oPosH = mul(float4(iPosL, 1.0f), gWVP);
// Just pass vertex color into the pixel shader.
oColor = iColor;
}
float4 PS(float4 posH : SV_POSITION,
float4 color : COLOR) : SV_Target
{
return color;
}
technique10 ColorTech
{
pass P0
{
SetVertexShader( CompileShader( vs_4_0, VS() ) );
SetGeometryShader( NULL );
SetPixelShader( CompileShader( ps_4_0, PS() ) );
}
}
以上可以看成类c++的文件，就是定义一组操作。
然后通过
void ColoredCubeApp::buildVertexLayouts()
{
// Create the vertex input layout.
D3D10_INPUT_ELEMENT_DESC vertexDesc[] =
{
{"POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
{"COLOR", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0, 12, D3D10_INPUT_PER_VERTEX_DATA, 0}
};
// Create the input layout
D3D10_PASS_DESC PassDesc;
mTech->GetPassByIndex(0)->GetDesc(&PassDesc);
HR(md3dDevice->CreateInputLayout(vertexDesc, 2, PassDesc.pIAInputSignature,
PassDesc.IAInputSignatureSize, &mVertexLayout));
}
上面这个函数调用color.fx里面相应的操作函数实现图元的构建。
准备工作完成了。现在就是绘制过程了
void ColoredCubeApp::drawScene()
{
D3DApp::drawScene();
// Restore default states, input layout and primitive topology
// because mFont->DrawText changes them. Note that we can
// restore the default states by passing null.
//md3dDevice->OMSetDepthStencilState(0, 0);
float blendFactors[] = {0.0f, 0.0f, 0.0f, 0.0f};
//md3dDevice->OMSetBlendState(0, blendFactors, 0xffffffff);
md3dDevice->IASetInputLayout(mVertexLayout);
//图ª?元a列¢D表À¨ª-三¨y角?形?
md3dDevice->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_LINESTRIP);
// set constants
mWVP = mView*mProj;
mfxWVPVar->SetMatrix((float*)&mWVP);
D3D10_TECHNIQUE_DESC techDesc;
mTech->GetDesc( &techDesc );
for(UINT p = 0; p < techDesc.Passes; ++p)
{
mTech->GetPassByIndex( p )->Apply(0);//更¨¹新?GPU 常¡ê量¢?缓o冲?区?，ê?将?着Á?色¦?器¡Â绑㨮定¡§到Ì?管¨¹线?，ê?启?动¡¥pass
mBox.draw();
}
mSwapChain->Present(0, 0);
}
void ColoredCubeApp::updateScene(float dt)
{
D3DApp::updateScene(dt);
// Update angles based on input to orbit camera around box.
if(GetAsyncKeyState('A') & 0x8000) mTheta -= 2.0f*dt;
if(GetAsyncKeyState('D') & 0x8000) mTheta += 2.0f*dt;
if(GetAsyncKeyState('W') & 0x8000) mPhi -= 2.0f*dt;
if(GetAsyncKeyState('S') & 0x8000) mPhi += 2.0f*dt;
// Restrict the angle mPhi.
if( mPhi < 0.1f ) mPhi = 0.1f;
if( mPhi > PI-0.1f) mPhi = PI-0.1f;
// Convert Spherical to Cartesian coordinates: mPhi measured from +y
// and mTheta measured counterclockwise from -z.
float x = 5.0f*sinf(mPhi)*sinf(mTheta);
float z = -5.0f*sinf(mPhi)*cosf(mTheta);
float y = 5.0f*cosf(mPhi);
// Build the view matrix. 观?察¨¬者?到Ì?世º¨¤界?的Ì?矩?阵¨®
D3DXVECTOR3 pos(x, y, z);
D3DXVECTOR3 target(0.0f, 0.0f, 0.0f);
D3DXVECTOR3 up(0.0f, 1.0f, 0.0f);
D3DXMatrixLookAtLH(&mView, &pos, &target, &up);
}
目前还只是第一个比较完整的demo 细节代码很多还没有理解透彻。我们能了解个大概流程就可以啦。后面会越学越懂的
DirectX10 龙书笔记- 一个颜色立方体程序
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