§8.1处理Post-Screen Shader

struct VertexInput

{

// We only need 2d screen position, that's all.

float2 pos : POSITION;

};

struct VB_OutputPos3DTexCoord

{

float4 pos : POSITION;

float3 texCoord : TEXCOORD0;

};

VB_OutputPos3DTexCoord VS_SkyCubeMap(VertexInput In)

{

VB_OutputPos3DTexCoord Out;

Out.pos = float4(In.pos.xy, 0, 1);

// Also negate xy because the cube map is for MDX (left handed)

// and is upside down

Out.texCoord = mul(float4(-In.pos, scale, 0), viewInverse).xyz;

// And fix rotation too (we use better x, y ground plane system)

Out.texCoord = float3( -Out.texCoord.x*1.0f, -Out.texCoord.z*0.815f, -Out.texCoord.y*1.0f);

return Out;

} // VS_SkyCubeMap(..)

float4 PS_SkyCubeMap(VB_OutputPos3DTexCoord In) : COLOR

{

float4 texCol = ambientColor * texCUBE(diffuseTextureSampler, In.texCoord);

return texCol;

} // PS_SkyCubeMap(.)

technique SkyCubeMap < string Script = "Pass=P0;"; > {

pass P0 < string Script = "Draw=Buffer;"; >

{

ZEnable = false;

VertexShader = compile vs_1_1 VS_SkyCubeMap();

PixelShader = compile ps_1_1 PS_SkyCubeMap();

}

// pass P0

} // technique

public static void TestSkyCubeMapping()

{

PreScreenSkyCubeMapping skyCube = null;

TestGame.Start("TestSkyCubeMapping", delegate

{

skyCube = new PreScreenSkyCubeMapping();

},

delegate

{

skyCube.RenderSky();

});

} // TestSkyCubeMapping()

AmbientColor = setSkyColor;

InverseViewMatrix = BaseGame.InverseViewMatrix;

// Start shader

// Remember old state because we will use clamp texturing here

effect.Begin(SaveStateMode.SaveState);

for (int num = 0; num < effect.CurrentTechnique.Passes.Count; num++)

{

EffectPass pass = effect.CurrentTechnique.Passes[num];

// Render each pass

pass.Begin();

VBScreenHelper.Render();

pass.End();

} // foreach (pass)

// End shader

effect.End();

public VBScreen()

{

VertexPositionTexture[] vertices = new VertexPositionTexture[] {

new VertexPositionTexture( new Vector3(-1.0f, -1.0f, 0.5f), new Vector2(0, 1)), new VertexPositionTexture( new Vector3(-1.0f, 1.0f, 0.5f), new Vector2(0, 0)), new VertexPositionTexture( new Vector3(1.0f, -1.0f, 0.5f), new Vector2(1, 1)), new VertexPositionTexture( new Vector3(1.0f, 1.0f, 0.5f), new Vector2(1, 0)), };

vbScreen = new VertexBuffer( BaseGame.Device, typeof(VertexPositionTexture), vertices.Length, ResourceUsage.WriteOnly, ResourceManagementMode.Automatic);

vbScreen.SetData(vertices);

decl = new VertexDeclaration(BaseGame.Device, VertexPositionTexture.VertexElements);

} // VBScreen()

// This script is only used for FX Composer, most values here

// are treated as constants by the application anyway.

// Values starting with an upper letter are constants.

float Script : STANDARDSGLOBAL

<

string ScriptClass = "scene";

string ScriptOrder = "postprocess";

string ScriptOutput = "color";

// We just call a script in the main technique.

string Script = "Technique=ScreenDarkenBorder;";

> = 0.5;

const float4 ClearColor : DIFFUSE = { 0.0f, 0.0f, 0.0f, 1.0f};

const float ClearDepth = 1.0f;

// Render-to-Texture stuff

float2 windowSize : VIEWPORTPIXELSIZE;

texture sceneMap : RENDERCOLORTARGET

<

float2 ViewportRatio = { 1.0, 1.0 };

int MIPLEVELS = 1;

>;

sampler sceneMapSampler = sampler_state

{

texture = <sceneMap>;

AddressU = CLAMP;

AddressV = CLAMP;

AddressW = CLAMP;

MIPFILTER = NONE;

MINFILTER = LINEAR;

MAGFILTER = LINEAR;

};

为使屏幕边界变暗你还使用了一个名为ScreenBorderFadeout.dds的贴图（见图8-5）：

// For the last pass we add this screen border fadeout map to darken the borders

texture screenBorderFadeoutMap : Diffuse

<

string UIName = "Screen border texture";

string ResourceName = "ScreenBorderFadeout.dds";

>;

sampler screenBorderFadeoutMapSampler = sampler_state

{

texture = <screenBorderFadeoutMap> ;

AddressU = CLAMP;

AddressV = CLAMP;

AddressW = CLAMP;

MIPFILTER = NONE;

MINFILTER = LINEAR;

MAGFILTER = LINEAR;

};

struct VB_OutputPos2TexCoords

{

float4 pos : POSITION;

float2 texCoord[2] : TEXCOORD0;

};

VB_OutputPos2TexCoords VS_ScreenQuad( float4 pos : POSITION, float2 texCoord : TEXCOORD0)

{

VB_OutputPos2TexCoords Out;

float2 texelSize = 1.0 / windowSize;

Out.pos = pos;

// Don't use bilinear filtering

Out.texCoord[0] = texCoord + texelSize*0.5; Out.texCoord[1] = texCoord + texelSize*0.5;

return Out;

} // VS_ScreenQuad(..)

float4 PS_ComposeFinalImage(VB_OutputPos2TexCoords In) : COLOR

{

float4 orig = tex2D(sceneMapSampler, In.texCoord[0]);

return orig;

}

// PS_ComposeFinalImage(...)

// ScreenDarkenBorder technique for ps_1_1

technique ScreenDarkenBorder <

// Script stuff is just for FX Composer

string Script = "RenderColorTarget=sceneMap;"

"ClearSetColor=ClearColor; Clear=Color;"

"ClearSetDepth=ClearDepth; Clear=Depth;"

"ScriptSignature=color; ScriptExternal=;"

"Pass=DarkenBorder;";

>

{

pass DarkenBorder <

string Script = "RenderColorTarget0=; Draw=Buffer;";

>

{

VertexShader = compile vs_1_1 VS_ScreenQuad();

PixelShader = compile ps_1_1 PS_ComposeFinalImage(sceneMapSampler);

} // pass DarkenBorder

} // technique ScreenDarkenBorder

return 1.0f - orig;

float4 orig = tex2D(sceneSampler, In.texCoord[0]);

float4 screenBorderFadeout =tex2D(screenBorderFadeoutMapSampler, In.texCoord[1]);

float4 ret = orig;

ret.rgb *= screenBorderFadeout;

return ret;

// Returns luminance value of col to convert color to grayscale

float Luminance(float3 col)

{

return dot(col, float3(0.3, 0.59, 0.11));

} // Luminance(.)

float4 ret = Luminance(orig);