1. Large-Scale Polygon Rendering

2. Solutions Decimation Visibility Culling Parallel Rendering Others

3. Surface Decimation Use a smaller number of triangles to represent the same surface -> preserve the topology Removing vertices Contracting edges Etc.

4. Visibility Culling Do not display polygons that are not visible to the eyes 188,000 triangles 1 million triangles

5. Parallel Rendering

6. 3D Rendering Pipeline Transformation Clipping (modeling, viewing, projection) Lighting Screen Projection Scan conversion Z-buffer Shading Geometry Processing Rasterization

7. Parallel Rendering GRGR display sequential GRGR GRGR GRGR GRGR GRGR GRGR display fully parallel

8. Parallel Rendering (2) Geometry processing: parallelized by assigning each processor a subset of primitives (polygons) Rasterization: parallelized by assigning each processor a portion of pixel calculations

9. Parallel Rendering (3) What is rendering anyway? Calculate the effect of each primitive on each pixel During transformation, a primitive can go anywhere on the screen Rendering can be seen as sorting primitives to the screen

10. Parallel Rendering (4) Rendering as a sorting process

11. Sorting primitives Where to sort? Sorting can pretty much happy anywhere Where/When to sort will affect the structure of the parallel rendering system GRGR GRGR GRGR GRGR GRGR GRGR display

12. Sort-First Parallel Rendering

13. Distribute the primitives early in the rendering pipeline P1 P2 P3P4 1.Subdivide the screen 2.“Pre-transform” the primitives 3.Distribute the primitives 4.Each processor render its own primitives 5.No communication needed afterwards P1: P2: P3: P4:

14. Sort-Middle Parallel Rendering

15. Distribute the primitives in the middle of pipeline P1: P2: P3: P4: P1 P2 P3P4 1. Arbitrary assignment 2. Geometry processing 3. Sorting P1: P2: P3: P4: Rasterization

16. Sort-Last Parallel Rendering

17. P1 P2 P3P4 Distribute the primitives in the end of pipeline P1: P2: P3: P4: GRGR GRGR GRGR GRGR 1. Arbitrary assignment 2. Geometry processing 3. Rasterization

18. Sort-Last Parallel Rendering P1 P2 P3 P4 P1 P2 P3P4 P1 P2 P3 P4 Sort images with z Compositing/z-buffer