Explication du fonctionnement des API 3D matériels, comme opengl, directx.
- 1. Le pipeline graphique temps rel Entres:
- 2. Surfaces, Lumires,
3. Cameras, 4. Surfaces de rendus Sorties:
- Couleurs rparties sur les surfaces de rendu selon ses
capacits
Modeling Transformations Illumination (Shading) Viewing
Transformation (Perspective / Orthographic) Clipping Projection(to
Screen Space) Scan Conversion (Rasterization) Visibility / Display
5. Modeling Transformations
- Les modles 3D sont dfinis dans leurs propre systme de
coordones. (object space)
6. Les Modeling transforms font le changement de repre (world
space) ModelingTransformations Illumination (Shading) Viewing
Transformation (Perspective / Orthographic) Clipping Projection(to
Screen Space) Scan Conversion (Rasterization) Visibility / Display
Object space World space 7. Illumination (Shading)
- Les Vertex sont illumins (shaded) selon les proprits des
matriaux, des surface (normal) et des lumires
8. Modles d'illumination (Diffuse, Ambient, Phong, etc.)
ModelingTransformations Illumination (Shading) Viewing
Transformation (Perspective / Orthographic) Clipping Projection(to
Screen Space) Scan Conversion (Rasterization) Visibility / Display
9. Viewing Transformation
- Transforme du world space vers eye space (Camera)
10. La position de visualisation est transform selon l'origine
& et sa direction est orient selon l'axe (en gnralz )
ModelingTransformations Illumination (Shading) Viewing
Transformation (Perspective / Orthographic) Clipping Projection(to
Screen Space) Scan Conversion (Rasterization) Visibility / Display
Eye space World space 11. Clipping ModelingTransformations
Illumination (Shading) Viewing Transformation (Perspective /
Orthographic) Clipping Projection(to Screen Space) Scan Conversion
(Rasterization) Visibility / Display Eye space frustum 12. Scan
Conversion (Rasterization)
- Rasterize les objets en pixels
13. Interpolation des valeurs 14. (couleur, pronfondeur, etc.)
ModelingTransformations Illumination (Shading) Viewing
Transformation (Perspective / Orthographic) Clipping Projection(to
Screen Space) Scan Conversion (Rasterization) Visibility / Display
15. Visibilit / Affichage
- Algorithme du peintre (Z-Buffer)
16. Chaque tape du pipeline est un forme de transformation
ModelingTransformations Illumination (Shading) Viewing
Transformation (Perspective / Orthographic) Clipping Projection(to
Screen Space) Scan Conversion (Rasterization) Visibility / Display
17. Systmes de Coordonnes
-
- deriv du frustum de visualisation
- Clip space / NormalizedDevice Coordinates (NDC)
-
- Index selon les capacits hardware
18. Systmes de Coordonnes ModelingTransformations Illumination
(Shading) Viewing Transformation (Perspective / Orthographic)
Clipping Projection(to Screen Space) Scan Conversion
(Rasterization) Visibility / Display Object space World space Eye
Space / Camera Space Clip Space (NDC) Screen Space 19. Matriel -
GPU 20. Matriel - GPU OpenGL (vertex) buffer object GPU command
processor vertex puller hardware rendering pipeline CPU CPU writes
of command + vertex indices vertex array GPU DMA transfer of
command data application (client) memory memory reads CPU GPU DMA
transfer of vertex dataCPU never reads data command queue 21.
Shaders
- Rsout la multiplicit de modles de transformation, de lumire
cabl en dur en donnant accs a des tapes du pipeline
Model dataVertex and texture coord VertexPrograms
FragmentPrograms Rasterization Framebuffer Fixed-functions
(lighting, clipping, culling, projection, viewport mapping)
Fixed-functions (pixel ownership testing, scissoring, alpha
testing, blending, masking) 22. Shader ambient lighting // Vertex
Shader void main() { gl_Position =gl_ModelViewProjectionMatrix *
gl_Vertex; } // Fragment Shader void main() { gl_FragColor =
vec4(0.2, 0.6, 0.8, 1); } 23. Shader ambient lighting
