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像素着色器替代了固定渲染管线的 多纹理化 阶段(书上说的)
这是片面的,不完善的, 其实像素着色器,只要渲染到屏幕上,那就有像素这个东西,就要有像素着色器.
实现步骤:
1.编写和编译像素着色器文件
2.创建像素着色器
3.设置像素着色器
//文本文件代码
//--------------------------begim ps.txt---------------------------------------
//全局变量
//存储颜色混合的比例值s，其中
//Scalar.x = s
//Scalar.y = 1-s
vector Scalar; //纹理混合比例(权重)
//纹理0; 纹理1
texture Tex0;
texture Tex1;
//纹理采样器0
sampler Samp0 = sampler_state
{
Texture = <Tex0>;
MipFilter = LINEAR;
MinFilter = LINEAR;
MagFilter = LINEAR;
};
//纹理采样器1
sampler Samp1 = sampler_state
{
Texture = <Tex1>;
MipFilter = LINEAR;
MinFilter = LINEAR;
MagFilter = LINEAR;
};
//输入两套纹理坐标
struct PS_INPUT
{
float2 uvCoords0 : TEXCOORD0;
float2 uvCoords1 : TEXCOORD1;
};
//输出像素颜色
struct PS_OUTPUT
{
float4 Color : COLOR0;
};
//入口函数
PS_OUTPUT PS_Main(PS_INPUT input)
{
PS_OUTPUT output = (PS_OUTPUT)0;
//分别对两个纹理进行采样按照比例混合后输出颜色值
output.Color = tex2D(Samp0, input.uvCoords0)*Scalar.x + tex2D(Samp1, input.uvCoords1)*Scalar.y;
return output;
}
//--------------------------end ps.txt---------------------------------------
vs程序中源代码:
//setup
void Setup()
{
HRESULT hr = 0;
//创建顶点缓存
m_d3dDevice->GetD3DDevice()->CreateVertexBuffer(
4 * sizeof(MultiTexVertex),
D3DUSAGE_WRITEONLY,
MultiTexVertex::FVF,
D3DPOOL_MANAGED,
&quadVB,
0);
//填充顶点缓存
MultiTexVertex* v = 0;
quadVB->Lock(0, 0, (void**)&v, 0);
v[0] = MultiTexVertex(-3.0f, -3.0f, 10.0f, 0.0f, 1.0f, 0.0f, 1.0f);
v[1] = MultiTexVertex(-3.0f, 3.0f, 10.0f, 0.0f, 0.0f, 0.0f, 0.0f);
v[2] = MultiTexVertex( 3.0f, -3.0f, 10.0f, 1.0f, 1.0f, 1.0f, 1.0f);
v[3] = MultiTexVertex( 3.0f, 3.0f, 10.0f, 1.0f, 0.0f, 1.0f, 0.0f);
quadVB->Unlock();
//加载纹理:
D3DXCreateTextureFromFile(D3DDevice, L"D:\\pic1.png", &quadTexture0);
D3DXCreateTextureFromFile(m_d3dDevice->D3DDevice, L"D:\\pic2.png", &quadTexture1);
//编译像素着色器:
//创建像素着色器
ID3DXBuffer* codeBuffer = 0;
ID3DXBuffer* errorBuffer = 0;
hr = D3DXCompileShaderFromFile(
L"D:\\ps.txt",
0,
0,
"PS_Main", // entry point function name
"ps_2_0",
D3DXSHADER_ENABLE_BACKWARDS_COMPATIBILITY,
&codeBuffer,
&errorBuffer,
&pixelConstTable);
// 输出错误信息:
if (errorBuffer)
{
string str = (char*)errorBuffer->GetBufferPointer();
MessageBox(NULL, Common::StringToWString(str).c_str(), L"ERROR", MB_OK);
//safe_release<ID3DXBuffer*>(error_buffer);
}
if (FAILED(hr))
{
MessageBox(NULL, L"D3DXCreateEffectFromFile() - FAILED", L"ERROR", MB_OK);
}
//创建像素着色器
hr = D3DDevice->CreatePixelShader((DWORD*)codeBuffer->GetBufferPointer(), &pixelShader);
if (FAILED(hr))
{
MessageBox(NULL, L"CreateVertexShader - FAILED", L"ERROR", MB_OK);
}
//释放
//safe_release<ID3DXBuffer*>(shader_buffer);
//设置投影矩阵
D3DXMATRIX p;
RECT rt;
GetClientRect(Application::GetInstance()->GetWnd(), &rt);
D3DXMatrixPerspectiveFovLH(&p, D3DX_PI * 0.25f, (float)rt.right / rt.bottom, 1.0f, 1000.0f);
D3DDevice->SetTransform(D3DTS_PROJECTION, &p);
//禁用灯光
D3DDevice->SetRenderState(D3DRS_LIGHTING, false);
//得到各常量句柄
ScalarHandle = pixelConstTable->GetConstantByName(0, "Scalar");
Samp0Handle = pixelConstTable->GetConstantByName(0, "Samp0");
Samp1Handle = pixelConstTable->GetConstantByName(0, "Samp1");
//设置对着色器变量Samp0、Samp1的描述
UINT count;
pixelConstTable->GetConstantDesc(Samp0Handle, &Samp0Desc, &count);
pixelConstTable->GetConstantDesc(Samp1Handle, &Samp1Desc, &count);
//设定各着色器变量为初始值
pixelConstTable->SetDefaults(D3DDevice);
}
//display : 设置像素着色器,取用2张纹理,并在渲染前设置对应采样状态
void Display(float timeDelta)
{
// render now
D3DDevice->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0x00000000, 1.0f, 0);
D3DDevice->BeginScene();
//为着色器全局变量Scalar赋值
D3DXVECTOR4 scalar(0.5f, 0.5f, 0.0f, 1.0f);//一半一半混合
pixelConstTable->SetVector(D3DDevice, ScalarHandle, &scalar);
//设置像素着色器
D3DDevice->SetPixelShader(pixelShader);
//设置定点格式、绑定数据流
D3DDevice->SetFVF(MultiTexVertex::FVF);
D3DDevice->SetStreamSource(0, quadVB, 0, sizeof(MultiTexVertex));
//设置第一、二层纹理
D3DDevice->SetTexture(Samp0Desc.RegisterIndex, quadTexture0);
D3DDevice->SetTexture(Samp1Desc.RegisterIndex, quadTexture1);
//绘制图形
D3DDevice->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);
D3DDevice->EndScene();
D3DDevice->Present(NULL, NULL, NULL, NULL);
}
