1. Accelerated Stereoscopic Rendering using GPU François de Sorbier - Université Paris-Est France February 2008 WSCG'2008

2. WSCG'2008 - February 2008 Problematic 2 Introduction  Two-pass rendering  Computational time doubled

3. WSCG'2008 - February 2008 Shared attributes on vertices –Colour –Geometry –etc Use graphical processor  Duplicate the geometry  Transformations according to the viewpoint  Geometry Shaders Hypothesis 3 Introduction

4. WSCG'2008 - February 2008 Geometry shaders Our algorithm Results Conclusions Outline 4

5. WSCG'2008 - February 2008 Geometry Shader 5 Geometry shaders RASTERIZATION FRAMEBUFFER FRAGMENT SHADER VERTEX SHADER GEOMETRY SHADER

6. WSCG'2008 - February 2008 Example 6 Geometry shaders Input primitive Output primitives

7. WSCG'2008 - February 2008 Our method overview 7 Our Algorithm View 1 View 2 Geometry Shader

8. WSCG'2008 - February 2008 Images generation 8 Our Algorithm Fragment shaders processing Fragment's origin Rendering buffer selection (Multiple Render Targets)‏ Standard operations Rendering into two textures Using FrameBuffer Object MRT + FBO involve constraints

9. WSCG'2008 - February 2008 Constraints 9 Our Algorithm No separated depth buffer  Use painter algorithm on objects  Back Face Culling Have to render a fragment into the two buffers  Colour and alpha set to 0  Mix function for blending

10. WSCG'2008 - February 2008 10 Our Algorithm

11. WSCG'2008 - February 2008 Improvement hypothesis 11 Our Algorithm ?

12. WSCG'2008 - February 2008 Algorithm 12 Our Algorithm Get depth map Transmit vertices' position with duplicated geometry (GS)‏ Apply our own depth test (FS)‏ Get correct position in the depth map Comparison with current fragment depth

13. WSCG'2008 - February 2008 13 Our Algorithm

14. WSCG'2008 - February 2008 Results 14 Results  nVidia GeForce 8800 GTX  80.000 triangles

15. WSCG'2008 - February 2008 Conclusions 15 Conclusion Limitations  “home made” depth test Advantages  Only one rendering pass  Reduces computational time  First release of geometry shader

16. WSCG'2008 - February 2008 Extensions 16 Conclusion Depth test enhancement –Separated depth buffers? –Algorithm? Autostereoscopic screens –Up to 8 views (first results)

17. WSCG'2008 - February 2008 17 Thank you! francois.desorbier@univ-paris-est.fr