Overview
Rasterization projects primitives such as triangles onto the image plane and fills the pixels they cover.
FoundationSource checked
Rasterization
Converts geometric shapes into pixels on a screen.
Quick Facts
Compact metadata for implementation and discovery.
- Category
- Rendering
- Difficulty
- Intermediate
- Family
- Image Synthesis
- Tier
- Foundation
- Status
- Verified
- Review
- Source Checked
- Sources
- 1
- Formulas
- 1
- Relationships
- 11
- Code example
- Not ready
- Visualization
- Ready
Core Concepts
screen-space primitivefragmentattribute interpolationfill rule
Quick facts
Complexity
Runtime and memory behavior at a glance.
Best
O(p)
Average
O(p)
Worst
O(p)
Space
O(p)
When to Use
- Use it for fast image generation from triangles, lines, or other primitives.
- Use it when real-time performance matters more than physically complete light transport.
- Use it when visibility and interpolation can be handled per fragment.
When Not to Use
- Avoid it when global illumination or physically accurate light paths are the main requirement.
- Avoid it when the scene cannot be represented as rasterizable primitives.
- Avoid relying on it alone for effects that require secondary visibility, such as reflections through multiple bounces.
What It Does
- Projects geometry to screen space
- Fills covered pixels
Use Cases
- Real-time graphics
- Game rendering
- Drawing vector shapes
Inputs
- Geometry
- Camera or projection
- Surface attributes
Outputs
- Pixels or fragments
Key Formulas (1)
Barycentric interpolation
point = w1 · vertex1 + w2 · vertex2 + w3 · vertex3
point = w1 * vertex1 + w2 * vertex2 + w3 * vertex3Interpolates positions or attributes across a triangle when the weights are inside the triangle.
Pseudocode
- 1.Transform vertices into screen space
- 2.Find the pixels covered by each primitive
- 3.Interpolate attributes for each covered pixel
- 4.Shade each fragment
- 5.Write visible fragments to the image
Canonical Example
- Input
- triangle vertices in screen space: (1,1), (5,1), (3,4)
- Output
- the set of pixels covered by the triangle
- Explanation
- Rasterization identifies the pixels inside the projected triangle and produces fragments for shading.
Implementation Notes
- Transform vertices into clip space, perform clipping, then map to screen coordinates.
- Use a consistent fill convention for pixels on triangle edges.
- Interpolate depth and attributes with the same perspective rules used by the pipeline.
Common Pitfalls
- Mixing coordinate spaces between object, world, clip, and screen coordinates.
- Ignoring sampling and edge rules, which can create cracks or missing pixels.
- Forgetting that rasterization alone does not model indirect lighting.
Interactive Mechanism Walkthrough
Spatial Primitive & Sweep-Line CanvasShow a triangle projected and filled as a grid of pixels.
Step 1 of 5: Transform vertices into screen space
triangle-to-pixelsNotes
Rasterization is usually paired with a visibility method such as z-buffering.
Sources (1)
What each reference supports for this entry.
Real-Time Rendering
BookComputer graphics reference covering rasterization and real-time rendering pipelines.
Open sourceExplore Next
Good next jumps from the relationship graph, ranked for useful discovery.
Alternative toRay Tracing
Rendering · Foundation
Rasterization and ray tracing are different rendering pipelines.
Compare with thisUsesZ-Buffering
Rendering · Foundation
Raster pipelines commonly use depth buffering for visibility.
Compare with thisUsed byForward Rendering
Rendering · Core
Forward rendering shades objects during rasterization passes.
Compare with thisUsesMipmapping
Rendering · Core
Raster pipelines use mipmaps to reduce texture aliasing.
Compare with thisRelationships
View full relationship pageUsed byDeferred Shading
Deferred shading starts with rasterized geometry buffers.
Used byForward Rendering
Forward rendering shades objects during rasterization passes.
Alternative toRay Tracing
Rasterization and ray tracing are different rendering pipelines.
GeneralizesScanline Rendering
Scanline rendering is a classic rasterization strategy.
UsesZ-Buffering
Raster pipelines commonly use depth buffering for visibility.
Related Algorithms
Tags
GraphicsGeometryVisibilityClassic