Overview
Parallax occlusion mapping simulates depth in a material by stepping along the view ray through a height map and using the hit point for texture lookup.
ExtendedSource checked
Parallax Occlusion Mapping
Offsets texture coordinates by ray-marching through a height field on the surface.
Quick Facts
Compact metadata for implementation and discovery.
- Category
- Rendering
- Difficulty
- Advanced
- Family
- Surface Detail
- Tier
- Extended
- Status
- Verified
- Review
- Source Checked
- Sources
- 1
- Formulas
- 1
- Relationships
- 3
- Code example
- Ready
- Visualization
- Ready
Core Concepts
height mapview raytexture-coordinate offsetself-occlusion
Quick facts
Complexity
Runtime and memory behavior at a glance.
Best
O(steps)
Average
O(pixels * steps)
Worst
O(pixels * steps)
Space
O(1)
When to Use
- Use when real-time graphics needs height map.
- Use when the input matches the assumptions behind surface Detail.
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
- Offsets texture coordinates by ray-marching through a height field on the surface
- Uses height map and view ray 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)
Parallax step
uvnext = uv + viewxy · stepsize
uv_next = uv + view_xy * step_sizeMoves texture coordinates along the projected view direction.
Pseudocode
- 1.Prepare the inputs and state needed for Parallax Occlusion Mapping.
- 2.Apply the height map step while the stopping condition has not been met.
- 3.Update intermediate state and discard invalid candidates.
- 4.Return rendered image.
Canonical Example
- Input
- Parallax Occlusion Mapping input with a small representative case
- Output
- Rendered image
- Explanation
- Parallax Occlusion Mapping applies height map to produce rendered image.
Implementation Notes
- Keep the data space for positions, normals, and samples explicit in the implementation.
- Keep the height map step separate enough to test independently.
Common Pitfalls
- Mixing coordinate spaces or sampling domains leads to artifacts that are hard to debug.
- Forgetting to check edge cases can make Parallax Occlusion Mapping look correct on 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 Parallax Occlusion Mapping.
rendering-mechanismNotes
Parallax Occlusion Mapping should be used with the assumptions and tradeoffs of surface Detail in mind.
Sources (1)
What each reference supports for this entry.
Tatarchuk 2006
PaperReference for practical parallax occlusion mapping with approximate soft shadows.
Open sourceExplore Next
Good next jumps from the relationship graph, ranked for useful discovery.
Relationships
View full relationship pageImproves onNormal Mapping
Parallax occlusion mapping adds view-dependent depth effects beyond normal perturbation.
Conceptual neighborRay Marching
It often marches through a height field along a view direction.
Related Algorithms
Tags
GraphicsTexture MappingRay MarchingShading