Overview
Multisample anti-aliasing stores several coverage samples for each pixel while usually shading less often than full supersampling.
CoreSource checked
MSAA
Reduces geometric aliasing by sampling coverage multiple times per pixel.
Quick Facts
Compact metadata for implementation and discovery.
- Category
- Rendering
- Difficulty
- Intermediate
- Family
- Anti-Aliasing
- Tier
- Core
- Status
- Verified
- Review
- Source Checked
- Sources
- 1
- Formulas
- 1
- Relationships
- 4
- Code example
- Ready
- Visualization
- Ready
- Aliases
- Multisample Anti-Aliasing
Core Concepts
coverage samplingsample resolveraster edgesubpixel mask
Quick facts
Complexity
Runtime and memory behavior at a glance.
Best
O(samples)
Average
O(pixels * samples)
Worst
O(pixels * samples)
Space
O(pixels * samples)
When to Use
- Use when real-time graphics needs coverage sampling.
- Use when the input matches the assumptions behind anti-Aliasing.
When Not to Use
- Avoid when the effect costs more than the visual improvement for the target hardware.
- Avoid when a simpler algorithm gives the required result with less setup.
What It Does
- Reduces geometric aliasing by sampling coverage multiple times per pixel
- Uses coverage sampling and sample resolve to guide the work.
- Produces rendered image.
Use Cases
- Real-time graphics
- Offline rendering
- Lighting and visibility effects
Inputs
- Scene geometry
- Materials
- Camera and lighting state
Outputs
- Rendered image
- Visibility or shading buffers
Key Formulas (1)
Sample resolve
pixelcolor = average(coveredsamples)
pixel_color = average(covered_samples)Combines covered subsamples into the final pixel color.
Pseudocode
- 1.Prepare the inputs and state needed for MSAA.
- 2.Apply the coverage sampling step while the stopping condition has not been met.
- 3.Update intermediate state and discard invalid candidates.
- 4.Return rendered image.
Canonical Example
- Input
- MSAA input
- Output
- Rendered image
- Explanation
- MSAA applies coverage sampling to produce rendered image.
Implementation Notes
- Keep the data space for positions, normals, and samples explicit in the implementation.
- Keep the coverage sampling step separate enough to test independently.
Common Pitfalls
- Mixing coordinate spaces or sampling domains leads to artifacts that are hard to debug.
- Test boundary and adversarial cases, not only ideal inputs.
Interactive Mechanism Walkthrough
Spatial Primitive & Sweep-Line CanvasShow rays, samples, buffers, or shading terms that contribute to the final pixel.
Step 1 of 4: Prepare the inputs and state needed for MSAA.
rendering-mechanismNotes
MSAA should be used with the assumptions and tradeoffs of anti-Aliasing in mind.
Sources (1)
What each reference supports for this entry.
Real-Time Rendering
BookComputer graphics reference for raster pipelines, shading, antialiasing, texture filtering, and real-time rendering techniques.
Open sourceExplore Next
Good next jumps from the relationship graph, ranked for useful discovery.
Relationships
View full relationship pageAlternative toFXAA
MSAA uses multisample coverage rather than a post-process edge filter.
Alternative toTemporal Anti-Aliasing
MSAA resolves within a frame instead of accumulating over time.
Related Algorithms
Tags
GraphicsAnti-AliasingRasterizationSampling