Per-Sample Processing

OpenGL Rendering Pipeline

Rendering Pipeline Overview

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• Vertex Specification
  • Vertex Rendering
  • Primitive
• Vertex Processing
  • Vertex Shader
  • Tessellation
  • Geometry Shader
• Vertex Post-Processing
  • Transform Feedback
• Primitive Assembly
• Rasterization
• Fragment Shader
• Per-Sample Processing
  • Scissor Test
  • Stencil Test
  • Depth Test
  • Blending
  • Logical Operation
  • Write Mask

Per-Sample Processing is a stage of the OpenGL rendering pipeline, where fragment data output from a Fragment Shader is processed and written to various buffers. There are a number of operations that are performed in the order below.

Scissor test

Main article: Scissor Test

Stencil test

Main article: Stencil Test

Depth test

Main article: Depth Test

Occlusion query updating

Fragments at this point are considered to have passed any conditional tests. Thus, their outputs will be written to one or more buffers (Write Masks not withstanding). As such, this is the point where the fragment is counted for Occlusion Query counters. If an occlusion query of type GL_SAMPLES_PASSED​ is active, then the query will be incremented every time a fragment hits this stage.

Blending

Main article: Blending

Logic operations

Main article: Logical Operation

Write mask

Main article: Write Mask