程式師世界 >> 編程語言 >> C語言 >> C++ >> C++入門知識 >> D3D三層Texture紋理經像素著色器實現渲染YUV420P，textureyuv420p

D3D三層Texture紋理經像素著色器實現渲染YUV420P，textureyuv420p

編輯：C++入門知識

D3D三層Texture紋理經像素著色器實現渲染YUV420P，textureyuv420p

簡單記錄一下這兩天用Texture實現渲染YUV420P的一些要點。

在視頻播放的過程中，有的時候解碼出來的數據是YUV420P的。表面（surface）通過設置參數是可以渲染YUV420P的，但Texture紋理似乎不支持直接渲染YUV420P。表面（surface）用法似乎比較單一，通常用來顯示數據，用Texture的話就可以用上D3D的許多其他功能，做出一些效果。當然，這看個人需求，通常而言顯示視頻數據用表面就夠了。

1.利用像素著色器把YUV420P數據轉為RGB32

視頻播放過程中幀與幀之間是有固定時間間隔的。若解碼解出來的是YUV420P的數據，要用Texture渲染的話，就需要把數據轉為RGB32的（應該是要轉成RGB32的，沒做過詳細調查，看到的例子中紋理所用的數據都是RGB32的），如果這個過程交給CPU去做的話，會提高CPU的占用率，用GPU來做這項工作則就釋放了CPU的一部分壓力。

本文考慮的方式是用三層紋理分別存放YUV420P的Y、U、V分量（這個詞不知道用對沒有），然後像素著色器把三個分量的數據計算成RGB32的數據然後顯示。這是本文的核心內容。

像素著色器的HLSL代碼如下：

sampler YTex;
sampler UTex;
sampler VTex;


struct PS_INPUT
{
    float2 y    : TEXCOORD0;
    float2 u    : TEXCOORD1;
    float2 v    : TEXCOORD2;
};


float4 Main(PS_INPUT input):COLOR0
{      
    float y = tex2D(YTex,input.y).r;
    float u = tex2D(UTex, input.u.xy / 2).r  - 0.5f;
    float v = tex2D(VTex,input.v.xy / 2).r  - 0.5f;            
                
    float r = y + 1.14f * v;
    float g = y - 0.394f * u - 0.581f * v;
    float b = y + 2.03f * u;
                
    return float4(r,g,b, 1);
}

HLSL代碼可以直接寫在txt文件中，sampler可視作標識紋理層和采樣級的對象，Direct3D將把每一個sampler對象唯一地與某一紋理層關聯起來。具體的HLSL語法請自行查資料，我也是粗略知道是怎麼回事，就不誤人子弟了。在代碼中通過調用D3DXCompileShaderFromFile函數可以從文件編譯像素著色器。但實際上，我個人不是很喜歡這種把代碼放在一個單獨文件裡面的做法，這種代碼應該盡可能的編進exe裡面。但是我還只是初步了解D3D，不知道怎麼把它編進exe裡面，如果有人知道，還望指教。

ID3DXBuffer* shader      = 0;
ID3DXBuffer* errorBuffer = 0;

hr = D3DXCompileShaderFromFile(
    "ps_multitex.txt",
    0,
    0,
    "Main", // entry point function name
    "ps_2_0",
    D3DXSHADER_DEBUG, 
    &shader,
    &errorBuffer,
    &MultiTexCT);

// output any error messages
if( errorBuffer )
{
    ::MessageBox(0, (char*)errorBuffer->GetBufferPointer(), 0, 0);
    d3d::Release<ID3DXBuffer*>(errorBuffer);
}

if(FAILED(hr))
{
    ::MessageBox(0, "D3DXCompileShaderFromFile() - FAILED", 0, 0);
    return false;
}

//
// Create Pixel Shader
//
hr = Device->CreatePixelShader(
    (DWORD*)shader->GetBufferPointer(),
    &MultiTexPS);

if(FAILED(hr))
{
    ::MessageBox(0, "CreateVertexShader - FAILED", 0, 0);
    return false;
}

d3d::Release<ID3DXBuffer*>(shader);

以上代碼中，D3DXCompileShaderFromFile函數從文件ps_multitex.txt編譯HLSL代碼；參數Main是HLSL代碼的入口函數，如上一點代碼中所見。這個入口函數可以是自定義的其他的，但要注意保持一致；ps_2_0表示像素著色器的版本。CreatePixelShader函數創建像素著色器。

2.sampler與紋理關聯

創建紋理層。本文實現YUV420P渲染的方法采用了三層紋理，每層紋理分別存放Y、U、V數據。

Device->CreateTexture ( Width, Height, 1, D3DUSAGE_DYNAMIC, D3DFMT_L8, D3DPOOL_DEFAULT, &YTex, NULL ) ;
Device->CreateTexture ( Width / 2, Height / 2, 1, D3DUSAGE_DYNAMIC, D3DFMT_L8, D3DPOOL_DEFAULT, &UTex, NULL ) ;
Device->CreateTexture ( Width / 2, Height / 2, 1, D3DUSAGE_DYNAMIC, D3DFMT_L8, D3DPOOL_DEFAULT, &VTex, NULL ) ;

sampler與紋理的關聯

// 
// Get Handles
//

YTexHandle      = MultiTexCT->GetConstantByName(0, "YTex");
UTexHandle        = MultiTexCT->GetConstantByName(0, "UTex");
VTexHandle        = MultiTexCT->GetConstantByName(0, "VTex");

//
// Set constant descriptions:
//

UINT count;

MultiTexCT->GetConstantDesc(YTexHandle,      &YTexDesc, &count);
MultiTexCT->GetConstantDesc(UTexHandle, &UTexDesc, &count);
MultiTexCT->GetConstantDesc(VTexHandle,    &VTexDesc, &count);

MultiTexCT->SetDefaults(Device);

設置紋理/sampler的狀態，這一部分我是在渲染的時候做的，也可以直接寫在HLSL代碼中。在後面渲染部分還會見到這些代碼，其實是同一段代碼，我只是為了表述紋理與sampler關聯的一個整體過程，把它預先從渲染部分截了出來，希望不會造成誤解。

// Y tex
Device->SetTexture(     YTexDesc.RegisterIndex, YTex);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_ADDRESSU, D3DTADDRESS_BORDER);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_ADDRESSV, D3DTADDRESS_BORDER);

// U tex
Device->SetTexture(     UTexDesc.RegisterIndex, UTex);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_ADDRESSU, D3DTADDRESS_BORDER);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_ADDRESSV, D3DTADDRESS_BORDER);

// string tex
Device->SetTexture(     VTexDesc.RegisterIndex, VTex);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_ADDRESSU, D3DTADDRESS_BORDER);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_ADDRESSV, D3DTADDRESS_BORDER);

3.渲染YUV420P

獲得YUV420P數據。本文直接讀取的YUV420P數據。

打開文件代碼：

if((infile=fopen("test_yuv420p_320x180.yuv", "rb"))==NULL){
    printf("cannot open this file\n");
    return false;
}

讀取數據並將數據copy到紋理中：

if (fread(buf, 1, Width*Height*3/2, infile) != Width*Height*3/2){
        // Loop
        fseek(infile, 0, SEEK_SET);
        fread(buf, 1, Width*Height*3/2, infile);
    }


//
// Render
//

Device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0);

plane[0] = buf;
plane[1] = plane[0] + Width*Height;
plane[2] = plane[1] + Width*Height/4;

D3DLOCKED_RECT d3d_rect;
byte *pSrc = buf;
//Locks a rectangle on a texture resource.
//And then we can manipulate pixel data in it.
LRESULT lRet = YTex->LockRect(0, &d3d_rect, 0, 0);
if (FAILED(lRet)){
    return false;
}
// Copy pixel data to texture
byte *pDest = (byte *)d3d_rect.pBits;
int stride = d3d_rect.Pitch; 
for(int i = 0;i < Height;i ++){
    memcpy(pDest + i * stride,plane[0] + i * Width, Width);
}

YTex->UnlockRect(0);

D3DLOCKED_RECT d3d_rect1;
lRet = UTex->LockRect(0, &d3d_rect1, 0, 0);
if (FAILED(lRet)){
    return false;
}
// Copy pixel data to texture
byte *pDest1 = (byte *)d3d_rect1.pBits;
int stride1 = d3d_rect1.Pitch; 
for(int i = 0;i < Height/2;i ++){
    memcpy(pDest1 + i * stride1 / 2,plane[1] + i * Width / 2, Width / 2);
}

UTex->UnlockRect(0);

D3DLOCKED_RECT d3d_rect2;
lRet =  VTex->LockRect(0, &d3d_rect2, 0, 0);
if (FAILED(lRet)){
    return false;
}
// Copy pixel data to texture
byte *pDest2 = (byte *)d3d_rect2.pBits;
int stride2 = d3d_rect2.Pitch; 
for(int i = 0;i < Height/2;i ++){
    memcpy(pDest2 + i * stride2 / 2,plane[2] + i * Width / 2, Width / 2);
}

VTex->UnlockRect(0);

渲染：

Device->BeginScene();

Device->SetPixelShader(MultiTexPS);
Device->SetFVF(MultiTexVertex::FVF);
Device->SetStreamSource(0, QuadVB, 0, sizeof(MultiTexVertex));

// Y tex
Device->SetTexture(     YTexDesc.RegisterIndex, YTex);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_ADDRESSU, D3DTADDRESS_BORDER);
Device->SetSamplerState(YTexDesc.RegisterIndex, D3DSAMP_ADDRESSV, D3DTADDRESS_BORDER);

// U tex
Device->SetTexture(     UTexDesc.RegisterIndex, UTex);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_ADDRESSU, D3DTADDRESS_BORDER);
Device->SetSamplerState(UTexDesc.RegisterIndex, D3DSAMP_ADDRESSV, D3DTADDRESS_BORDER);

// string tex
Device->SetTexture(     VTexDesc.RegisterIndex, VTex);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_ADDRESSU, D3DTADDRESS_BORDER);
Device->SetSamplerState(VTexDesc.RegisterIndex, D3DSAMP_ADDRESSV, D3DTADDRESS_BORDER);

Device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2);

Device->EndScene();
Device->Present(0, 0, 0, 0);

D3D Texture紋理渲染YUV420P的主要就是以上一些內容。完整工程代碼：http://download.csdn.net/download/qq_33892166/9702415

本文的HLSL代碼寫出來的像素著色器畫面有些偏黃，知道如何優化的朋友還請指教。