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Game Programming Tricks

Part INext-Gen Shaders

Korhan BircanApril 8th, 2008

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Shader Models

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Post Processing EffectsBlur – Combine pixel color with surrounding pixel colorsMotion Blur – Combine current frame with previous frame(s)Depth of Field – Blur pixel based on their depth valueHDR effects – Bloom, lens flare etc.Magnify bright spots Edge Glow – Find edges and blur themParallax Mapping – improved bump mapping

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Gaussian Blur// f(x) = a*e^-((x-b)^2)/r// a = 1; b = 0; r = radius;// f(x) = pow(e, -(x)^2/r)weights[i*width + j] = pow(E, -pow(dist, 2.0)*_1_over_r) );// usually just have a precomputed table

float4 PostProcessPS(float2 Tex : TEXCOORD0) : COLOR0{

float4 Color = 0;

for (int i = 0; i < m_KernelSize; i++){

Color += tex2D(m_SrcColor, Tex + TexelKernel[i].xy ) * weights[i];

}

return Color;}

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Gaussian Blur

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Radial Blur

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Radial Blur

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Motion Blur

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Depth of Field

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Depth of Field

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Depth of Field

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Depth of Field

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Haze

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Haze

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Haze

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Haze

1

32

64

96

128

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Haze

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Haze – Particle System

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High Dynamic Range (HDR) Rendering

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HDR Rendering

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HDR Rendering

•down filter 4x

•bright pass

•bloom horizontal

•bloom vertical

•up filter 4x

•combine

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HDR Rendering

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Exposure Control

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Glow

•edge detection

•down filter 4x

•blur horizontal

•blur vertical

•combine 4x

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Light Streaks

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Lens Flare

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Parallax Mapping

diffuse shading bump mapping parallax mapping

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Bump Mapping

texture map

height map

bump map

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Parallax Mappingbump mapping:

naive parallax mapping:

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Parallax Mapping

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Steep Parallax Mapping

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References•Shaders for Game Programmers and Artists, Sebastian St-Laurent

•Programming Vertex and Pixel Shaders, Wolfgang Engel

•DirectX SDK Documentation

•NVIDIA Gpu Gems Series

•Steep Parallax Mapping, Morgan McGuire, Max McGuire