1. Adding Surface Detail
고려대학교 컴퓨터 그래픽스 연구실

2. 3D Rendering Pipeline Surface details can be added... 3D Primitives
3D Modeling Coordinates
Model Transformation
3D World Coordinates
Lighting
3D World Coordinates
Viewing Transformation
3D Viewing Coordinates
Projection Transformation
Surface details
can be added...
2D Projection Coordinates
Clipping
2D Projection Coordinates
Viewport Transformation
2D Device Coordinates
Scan Conversion
2D Device Coordinates
Image

3. Overview Texture mapping methods Texture mapping applications Mapping
Filtering
Texture mapping applications
Modulation texture
Bump mapping
Environment mapping

4. Texture Surface Add visual detail to surfaces of 3D objects
With Surface Texture
Polygonal Model

5. Texture Mapping 2D projective transformation
Texture coordinate system (s, t) to
Device coordinate system (x, y)

6. Viewing and Projection
Textures
Color variation in interior of 3D polygon
When scan converting a polygon
Vary pixel colors according to values fetched from a texture y ys t
Texture-Surface
Transformation
Viewing and Projection
Transformation x s xs z
Texture Space
Object Space
Image Space

7. Texture Mapping Steps: Define texture
Specify mapping from texture to surface
Lookup texture values during scan conversion
(0, 1)
(1, 0) t v y s u
(0, 0) x
Texture
Coordinate
System
Modeling
Coordinate
System
Device
Coordinate
System

8. Texture Mapping Scan conversion Interpolate texture coordinates
Distortion due to the bilinear interpolation
Subdivide the polygon into smaller ones α β 
(u1, v1)
(u3, v3)
(u2, v2)

9. Corrected Interpolation
Texture Mapping
Linear Interpolation
of Texture Coordinate
Corrected Interpolation

10. Texture Sampling To determine color at each pixel in image y ys t s xxs z

11. Texture Filtering To avoid aliasing problem Point Sampling
Corrected Result

12. Texture Filtering Ideally, use elliptically shaped convolution filters
In practice, use rectangles
Texture Space
Screen Space

13. Mip Maps Keep textures prefiltered at multiple resolutions
For each pixel
Linearly interpolate between two closest levels
Trilinear filtering
Fast and easy for hardware

14. Overview Texture mapping methods Texture mapping applications Mapping
Filtering
Texture mapping applications
Modulation texture
Bump mapping
Environment mapping

15. Modulation Texture
Texture
Shaded Color
Texture Value

16. Bump Mapping
Perturbate surface normals

17. Bump Mapping

18. Environment Mapping Map texture values to the environment map Surface
Pixel Projection
onto Environment
Map
Pixel Area
Projection
Reference Point

19. Summary Texture mapping methods Texture mapping applications Mapping
Filtering
Texture mapping applications
Modulation textures
Bump mapping
Environment mapping

20. Wireframe

21. Ambient Illumination Only

22. Flat Shaded Polygons with Diffuse Reflection

23. Gouraud Shaded Polygons with Diffuse Reflection

24. Gouraud Shaded Polygons with Specular Reflection

25. Phong Shaded Polygons with Specular Reflection

26. Curved Surfaces with Specular Reflection

27. Improved Illumination Model with Multiple Lights

28. Texture Mapping

29. Bump Mapping

30. Reflection Mapping