Deferred Shading Rasmus Vahtra, Andres Traks Forward rendering - - PowerPoint PPT Presentation

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Deferred Shading Rasmus Vahtra, Andres Traks Forward rendering - - PowerPoint PPT Presentation

Dec 07, 2022 220 likes β€’602 views

Deferred Shading Rasmus Vahtra, Andres Traks Forward rendering (non-deferred shading) Forward rendering (non-deferred shading) Forward rendering (non-deferred shading) Forward rendering (non-deferred shading) Depth culling Forward

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Deferred Shading

Rasmus Vahtra, Andres Traks

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Forward rendering (non-deferred shading)

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Forward rendering (non-deferred shading)

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Forward rendering (non-deferred shading)

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Forward rendering (non-deferred shading)

Depth culling

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Forward rendering (non-deferred shading)

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Forward shader: Vertex Shader (VS)

VS PS

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Forward shader: Pixel Shader (PS)

VS PS

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Complexity of forward rendering

For each light: For each object: Render() Blend results together

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Deferred shading

Shading done in a separate rendering pass Pass 1: Render object data into buffers Pass 2: Do lighting/shading

VS PS VS PS

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Deferred shading: 1) collect data into intermediate textures

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Deferred shading: 1) collect data into intermediate textures

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Deferred shading: 1) collect data into intermediate textures

Depth culling

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Deferred shading: 1) collect data into intermediate textures, done

Don’t care about geometry anymore

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Deferred shader: Vertex Shader (pass 1)

VS PS

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Deferred shader: Pixel Shader (pass 1)

VS PS

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Deferred shading: 1) collect data into intermediate textures, done

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Deferred shading: 2) Draw a full-screen quad

UV = (0, 0) (0, 1) (1, 1) (1, 0)

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Deferred shader: Pixel Shader (pass 2)

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Review

VS PS VS PS VS PS

Forward rendering: Deferred shading:

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Complexity of deferred rendering

For each object: Render geometry data Then shade each pixel on screen exactly once

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Deferred shading: VS Pass 2) Draw a full-screen quad

ID TexCoord Position (0, 0) (-1, 1, 0, 1) 1 (1, 0) (1, 1, 0, 1) 2 (0, 1) (-1, -1, 0, 1) 3 (1, 1) (1, -1, 0, 1)

VS PS

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Full screen triangle

UV = (0, 0) (0, 1) (1, 0) (1, 1) (0, 2) (2, 0)

A bit faster than a quad

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G-buffer

R G B A Diffuse RGB

  • Normal XYZ
  • Depth (32-bit)
  • 1920 x 1080 x 3 x 32 bits = 24 MB
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G-buffer: extra attributes

Battlefield 3 Killzone 2

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Packing normals

http://aras-p.info/texts/CompactNormalStorage.html π‘œ. 𝑦2 + π‘œ. 𝑧2 + π‘œ. 𝑨2 = 1 Works only with normalized view-space normals!

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Anti-aliasing

Edge-detect Blur if edge detected

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter09.html

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Transparent objects?

Render them after the deferred pass using forward shading

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Deferred lighting

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Modifying the G-buffer for deferred lighting

R G B A Diffuse RGB

  • Normal XYZ
  • Depth (32-bit)

Light Accumulation RGB

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Deferred lighting: G-Buffer

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Light Stencil Volumes

Each point light area is bounded by a sphere (approximate)

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Light Stencil Volumes

Each point light area is bounded by a sphere (approximate)

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Light Stencil Volumes

Each point light area is bounded by a sphere (approximate)

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Stencil shapes of lights

Fullscreen quad Fullscreen quad Sphere Cone

http://www.okino.com/new/toolkit/1-14.htm

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Other effects: Screen Space Ambient Occlusion (SSAO)

http://john-chapman-graphics.blogspot.co.uk/2013/01/ssao-tutorial.html