由于對(duì)于dxva2解碼得到的數(shù)據(jù)不宜copy回內(nèi)存給CPU處理，所以最好的辦法是在GPU上直接進(jìn)行處理。D3D的像素著色器能夠?qū)ο袼刂苯舆M(jìn)行操作，實(shí)現(xiàn)點(diǎn)運(yùn)算極其簡(jiǎn)單方便，簡(jiǎn)單的卷積運(yùn)算效果也非常好。但D3D9的限制也很多，對(duì)于過(guò)于復(fù)雜的圖像處理則顯得有些不能勝任。
1.點(diǎn)運(yùn)算
點(diǎn)運(yùn)算用HLSL非常容易實(shí)現(xiàn)，幾乎是公式怎么寫(xiě)，代碼就怎么寫(xiě)。以RGB轉(zhuǎn)灰度圖顯示為例：
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texture Tex0 ;int iFlag = 0 ;float aValue= 0.0 ;float bValue= 0.0 ;sampler2D YTex = sampler_state{ Texture = <Tex0> ; MipFilter = LINEAR ; MinFilter = LINEAR ; MagFilter = LINEAR ; AddressU = CLAMP ; AddressV = CLAMP ;};struct PS_INPUT{ float2 uvCoords0 : TEXCOORD0 ;};float4 Main( PS_INPUT input ) : COLOR0{ float4 yuvColor ; //rgb to gray 不知道是不是這么顯示的，姑且這么認(rèn)為 float gray = tex2D( YTex, input.uvCoords0 ).r * 0.299 + tex2D( YTex, input.uvCoords0 ).g * 0.587 + tex2D( YTex, input.uvCoords0 ).b * 0.114 ; float s = 0 ; if(iFlag == 0) { s = aValue * gray + bValue/255 ; } else if(iFlag == 1) { s = aValue * log(1+gray) ; } else if(iFlag == 2) { s = aValue * pow(abs(gray),bValue) ; } yuvColor.r = s ; yuvColor.g = s ; yuvColor.b = s ; yuvColor.a = 1.0 ; return yuvColor ;} |
點(diǎn)運(yùn)算如此簡(jiǎn)單是因?yàn)镚PU是并行運(yùn)算的，我個(gè)人認(rèn)為可以看成是每一個(gè)像素點(diǎn)（BGRA）對(duì)應(yīng)一個(gè)線程，這大概就是OpenCL中所謂的數(shù)據(jù)并行。這是一個(gè)非常簡(jiǎn)單的程序，指令數(shù)少，程序結(jié)構(gòu)也很簡(jiǎn)單，shader 的版本用2.0就可以輕松編過(guò)。
2.卷積運(yùn)算舉例
指令數(shù)較多的情況2.0版本的shader就搞不定了，上3.0版本可以做一些簡(jiǎn)單的卷積運(yùn)算。以中值濾波為例：
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texture Tex0 ;matrix WorldMatrix;matrix ViewMatrix;matrix ProjMatrix;sampler2D YTex = sampler_state{ Texture = <Tex0> ; MipFilter = LINEAR ; MinFilter = LINEAR ; MagFilter = LINEAR ; AddressU = CLAMP ; AddressV = CLAMP ;};struct VS_INPUT { float4 pos : POSITION; float4 color : COLOR0; float2 tex : TEXCOORD0; };// struct VS_OUTPUT { float4 pos : POSITION; float4 color : COLOR0; float2 tex : TEXCOORD0; };float2 g_v4ScreenSize;int ksize = 1 ;float fLeft = -1.0f ;float fTop = -1.0f ;float fRight = -1.0f ;float fBottom = -1.0f ;//--------------------------------- BurTechnique --------------------------------------VS_OUTPUT MainVS_Screen( VS_INPUT In ){ VS_OUTPUT Out = ( VS_OUTPUT )0; float4x4 matWorldView = mul(WorldMatrix,ViewMatrix); float4x4 matProject = mul(matWorldView,ProjMatrix); Out.pos = mul(In.pos,matProject); Out.tex = In.tex; Out.color = In.color; return Out;}float4 MainPS_Screen( VS_INPUT In ) : COLOR0{ float4 outColor = tex2D( YTex, In.tex ).rgba ; if(ksize <= 1 || ksize%2 == 0) { return outColor ; } if( ksize > 11 || ksize < 3) { return outColor ; } if(!(In.tex.x < fRight && In.tex.y < fBottom && In.tex.x > fLeft && In.tex.y > fTop)) { return outColor ; } // 紋理大小 float2 TexSize = float2( g_v4ScreenSize.x , g_v4ScreenSize.y ); float x_off = 1.0f / TexSize.x; float y_off = 1.0f / TexSize.y; float2 fX0Y0 = In.tex - float2(x_off * ksize/2, y_off*ksize/2) ; float3 sum = {0.0f, 0.0f, 0.0f} ; if(ksize >= 3) { sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*2)).rgb; } if(ksize >= 5) { sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*4)).rgb; } if(ksize >= 7) { sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*6)).rgb; } if(ksize >= 9) { sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*8)).rgb; } if(ksize >= 11) { sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 9, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*0)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*1)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*2)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*3)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*4)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*5)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*6)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*7)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*8)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 10, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*9)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 0, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 1, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 2, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 3, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 4, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 5, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 6, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 7, y_off*10)).rgb; sum += tex2D( YTex , fX0Y0 + float2(x_off * 8, y_off*10)).rgb; } outColor = float4(sum/(ksize*ksize),1.0f); return outColor ;}//--------------------------- 技術(shù)---------------------------technique BurTechnique{ pass P0 { LightEnable[0] = false; VertexShader = compile vs_3_0 MainVS_Screen(); PixelShader = compile ps_3_0 MainPS_Screen(); }} |
由于3.0版本的shader似乎不允許pixel shader單獨(dú)出現(xiàn)，所以我從點(diǎn)運(yùn)算用像素著色器實(shí)現(xiàn)改為用特效來(lái)實(shí)現(xiàn)。HLSL語(yǔ)法中有if語(yǔ)句，也有for語(yǔ)句，可是這個(gè)程序卻不厭其煩的把所有的都給列出來(lái)來(lái)，而沒(méi)有使用for循環(huán)。這是因?yàn)樵趯?shí)際使用中發(fā)現(xiàn)有一些限制，比如if語(yǔ)句的if（A>B）,A與B中必須有一個(gè)是常量，就像上面見(jiàn)到的那種形式；for循環(huán)中間的判斷也是如此，只是在第二層j循環(huán)中可以是第一層循環(huán)的i,即不可以
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for(int i=0;i<ksize;i++){ for(int j=0;j<ksize1;j++) { .......... }} |
以上代碼的ksize與ksize1都必須為常數(shù)，例外的情況是ksize1可以為第一層循環(huán)的 i 。這個(gè)問(wèn)題不知道后續(xù)版本的shader有沒(méi)有，反正我當(dāng)前使用的版本有。
另外有一個(gè)需要注意的地方是指令數(shù)，2.0版本的shader支持的指令數(shù)相當(dāng)少，3.0版本則要多好多，我最長(zhǎng)寫(xiě)到了400多條快500條時(shí)才導(dǎo)致編譯失敗。 還有一個(gè)需要提醒的是3.0版本的shader只支持D3D 9.0C以后的。如果要求做更為復(fù)雜的圖像處理，可以的話建議上D3D11，compute shader雖然我沒(méi)用過(guò)，但從介紹來(lái)說(shuō)，應(yīng)該可以處理一些更為復(fù)雜的圖像處理。
以上就是本文的全部?jī)?nèi)容，希望本文的內(nèi)容對(duì)大家的學(xué)習(xí)或者工作能帶來(lái)一定的幫助，同時(shí)也希望多多支持服務(wù)器之家！
原文鏈接：http://www.cnblogs.com/betterwgo/p/6403522.html
