C++ HLSL实现简单的图像处理功能

作者：三米上字体：[增加减小] 来源：互联网时间：2017-05-28

三米上通过本文主要向大家介绍了hlsl,hlsl教程,hlsl语言,cg/hlsl,hlsl 内置函数等相关知识,希望对您有所帮助,也希望大家支持linkedu.com www.linkedu.com

由于对于dxva2解码得到的数据不宜copy回内存给CPU处理，所以最好的办法是在GPU上直接进行处理。D3D的像素着色器能够对像素直接进行操作，实现点运算极其简单方便，简单的卷积运算效果也非常好。但D3D9的限制也很多，对于过于复杂的图像处理则显得有些不能胜任。

1.点运算

点运算用HLSL非常容易实现，几乎是公式怎么写，代码就怎么写。以RGB转灰度图显示为例：

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 不知道是不是这么显示的，姑且这么认为
  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 ;
}

</div>

点运算如此简单是因为GPU是并行运算的，我个人认为可以看成是每一个像素点（BGRA）对应一个线程，这大概就是OpenCL中所谓的数据并行。这是一个非常简单的程序，指令数少，程序结构也很简单，shader 的版本用2.0就可以轻松编过。

2.卷积运算举例

指令数较多的情况2.0版本的shader就搞不定了，上3.0版本可以做一些简单的卷积运算。以中值滤波为例：

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 ;
  }
  // 纹理大小
  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

分享到：QQ空间新浪微博腾讯微博微信百度贴吧 QQ好友复制网址打印

您可能想查找下面的文章:

C++ HLSL实现简单的图像处理功能

2017-05-28C++如何实现广义表详解
2017-05-28C++ 11和C++98相比有哪些新特性
2017-05-28C++中fstream,ifstream及ofstream用法浅析
2017-05-28C++检查某个文件或目录是否存在的函数
2017-05-28使用C语言求N的阶乘的方法
2017-05-28C++表达式new与delete知识详解
2017-05-28详解C++编程中的sizeof运算符与typeid运算符
2017-05-28C++ 异常处理 catch(...)介绍
2017-05-28深入解析C++中的引用类型
2017-05-28新旧MFC版本实现CEdit透明的2种方法的实例代码

C++ HLSL实现简单的图像处理功能

您可能想查找下面的文章:

相关文章

文章分类

最近更新的内容