RGB转HSV的shader

转帖以作备份

原帖：http://www.virtools.com.cn/bbs/viewthread.php?tid=7189&page=1

//Write By Jare 2011-01-01
[url=]//[email protected][/url] QQ:56788395
//#define HALF_PI 1.570795
bool UseRotate;
float2 rotation_Center <float2 Default = {0.5,0.5};>;
float rotation_Angle <float UIMin = 0.0; float UIMax = 6.2831853;> = 0.0;
//bool UseColor;
float color_Brightness <float UIMin = 0.0; float UIMax = 5.0;> = 1.0;
//float color_Gamma  <float UIMin = 0.0; float UIMax = 5.0;> = 1.0;
float4  color_AddColor <float4 Default = {1,1,1,0};>;
bool UseHue;
float hue_Hue   <float UIMin = 0.0; float UIMax = 1.0;> = 0.0;
float hue_Saturation <float UIMin = -1.0; float UIMax = 1.0;> = 0.0;
float hue_Brightness <float UIMin = -1.0; float UIMax = 1.0;> = 0.0;
float4 diff   : Diffuse;
texture RenderMap : TEXTURE;
float4x4 wvp  : WORLDVIEWPROJECTION; 
sampler RenderMapSampler3D = sampler_state
{
Texture = <RenderMap>;
MagFilter = LINEAR;
MinFilter = LINEAR;
// MipFilter = POINT;
};
sampler RenderMapSampler2D = sampler_state
{
Texture = <RenderMap>;
MagFilter = LINEAR;
MinFilter = LINEAR;
// MipFilter = POINT;
AddressU  = BORDER;
AddressV  = BORDER;
};
sampler RenderMapSampler2DPoint = sampler_state
{
Texture = <RenderMap>;
MagFilter = POINT;
MinFilter = POINT;
// MipFilter = POINT;
AddressU  = BORDER;
AddressV  = BORDER;
};
static float3 hue_All = float3(hue_Hue, hue_Saturation, hue_Brightness);
static float tcosA = cos(rotation_Angle);
static float tsinA = sin(rotation_Angle);
static float cosR = abs(tcosA) < 0.005 ? 0.0 : tcosA;
static float sinR = abs(tsinA) < 0.005 ? 0.0 : tsinA;
static float2x2 rotateMatrix = float2x2(cosR, sinR, -sinR ,cosR);
//static float tDeltaAngle = abs(rotation_Angle % HALF_PI);
static bool UseNearestColor = (cosR == 0.0 || sinR == 0.0);//(tDeltaAngle <= 0.005 || tDeltaAngle >= HALF_PI - 0.005);
//static sampler RenderMapSampler = Is3D ? RenderMapSampler3D : (UseNearestColor ? RenderMapSampler2DPoint : RenderMapSampler2D);
struct oVertex
{
float4 Pos  : POSITION;
float2 UV : TEXCOORD0;
};
float2 Rotate(float2 UV, float2 vCenter)
{
return mul(UV-vCenter, rotateMatrix) + vCenter;
}
oVertex VS(
float4 Pos : POSITION,
float2 UV : TEXCOORD0,
uniform bool Is3D
)
{
oVertex Out = (oVertex)0;
Out.Pos = Is3D ? mul(Pos,wvp) : Pos;
Out.UV = UV; 
return Out;
}
oVertex VS_Rotate(
float4 Pos : POSITION,
float2 UV : TEXCOORD0,
uniform bool Is3D
)
{
oVertex Out = VS(Pos,UV, Is3D);
if(UseRotate){
  Out.UV = Rotate(Out.UV, rotation_Center); 
}
return Out;
}
float4 PS(oVertex In) : COLOR0
{
float4 col;
if(UseNearestColor){
  col = tex2D(RenderMapSampler2DPoint, In.UV);
}else{
  col = tex2D(RenderMapSampler2D, In.UV);
}
return col * diff;
}
float4 PS_3D(oVertex In) : COLOR0
{
float4 col = tex2D(RenderMapSampler3D, In.UV);
return col * diff;
}
float __min_channel(float3 v)
{
  float t = (v.x<v.y) ? v.x : v.y;
  t = (t<v.z) ? t : v.z;
  return t;
}
float __max_channel(float3 v)
{
  float t = (v.x>v.y) ? v.x : v.y;
  t = (t>v.z) ? t : v.z;
  return t;
}
float3 rgb_to_hsv(float3 RGB)
{
float minVal = __min_channel(RGB);//min(min(RGB.x, RGB.y), RGB.z);
float maxVal = __max_channel(RGB);//max(max(RGB.x, RGB.y), RGB.z);
float delta = maxVal - minVal; //Delta RGB value 
float3 HSV;
HSV.y = delta / maxVal;
HSV.z = maxVal;
if (delta != 0.0) {    // If gray, leave H & S at zero
  float3 delRGB = (maxVal.xxx - RGB) / 6.0 / delta + 0.5;
  if ( RGB.x == maxVal )  HSV.x = delRGB.z - delRGB.y;
  else if ( RGB.y == maxVal ) HSV.x = delRGB.x - delRGB.z + 0.3333333333333;
  else/* RGB.z == maxVal*/ HSV.x = delRGB.y - delRGB.x + 0.6666666666667;
  HSV.x += 6.0;//don't know why
}
return (HSV);
}
float3 hsv_to_rgb(float3 HSV)
{
HSV.x = frac(HSV.x);
HSV.y = saturate(HSV.y);
HSV.z = saturate(HSV.z);
float3 RGB = HSV.z;
if ( HSV.y != 0 ) {
  float var_h = HSV.x * 6.0;
  int var_i = floor(var_h);
  
  float t1, t2;
  t1 = HSV.z * HSV.y;
  t2 = t1 * (var_h - var_i);
  float var_1 = HSV.z - t1;
  float var_2 = HSV.z - t2;
  float var_3 = var_1 + t2;
  
  if   (var_i == 1) RGB = float3(var_2, HSV.z, var_1);
  else if (var_i == 2) RGB = float3(var_1, HSV.z, var_3);
  else if (var_i == 3)  RGB = float3(var_1, var_2, HSV.z);
  else if (var_i == 4)  RGB = float3(var_3, var_1, HSV.z);
  else if (var_i == 5)  RGB = float3(HSV.z, var_1, var_2);
  else     RGB = float3(HSV.z, var_3, var_1);
}
return (RGB);
}
float4 changeColor(float4 col)
{
//if(UseColor){
  float colA = col.w;
  col.xyz *= color_Brightness;
  col = lerp(col, color_AddColor, color_AddColor.w);
  col.w = colA;
//}
if(UseHue){
  col.rgb = rgb_to_hsv(col.rgb);
  col.rgb += hue_All;
  col.rgb = hsv_to_rgb(col.rgb);
}
return col;
}
float4 PS_Color(oVertex In) : COLOR0
{
float4 col = PS(In);
return changeColor(col);
}
float4 PS_Color_3D(oVertex In) : COLOR0
{
float4 col = PS_3D(In);
return changeColor(col);
}
technique Base
{
pass p
{
  AlphaBlendEnable = true;
  DestBlend = INVSRCALPHA;
  SrcBlend = SRCALPHA;
  VertexShader = compile vs_1_1 VS_Rotate(false);
  PixelShader = compile ps_2_0 PS();
}
}
technique Base_3D
{
pass p
{
  AlphaBlendEnable = true;
  DestBlend = INVSRCALPHA;
  SrcBlend = SRCALPHA;
  VertexShader = compile vs_1_1 VS_Rotate(true);
  PixelShader = compile ps_2_0 PS_3D();
}
}
technique Base_ColorAndHue
{
pass p
{
  AlphaBlendEnable = true;
  DestBlend = INVSRCALPHA;
  SrcBlend = SRCALPHA;
  VertexShader = compile vs_1_1 VS_Rotate(false);
  PixelShader = compile ps_2_0 PS_Color();
}
}
technique Base_ColorAndHue_3D
{
pass p
{
  AlphaBlendEnable = true;
  DestBlend = INVSRCALPHA;
  SrcBlend = SRCALPHA;
  VertexShader = compile vs_1_1 VS_Rotate(true);
  PixelShader = compile ps_2_0 PS_Color_3D();
}
}