3D Game Programming Lab6- Bump Mapping

1. 3D Game ProgrammingLab6-Bump Mapping

2. Goal • 了解bump mapping的原理 • 懂得如何使用GLSL實作bump mapping • 自行製作bump map

3. The Perception

4. Bump Mapping • add bump map textures to models model bump map result

5. GLSL • Vertex shaders • change or get the information of vertices • Fragment shaders • mostly compute the color to be applied to a fragment

6. Bump Mapping in GLSL MCVertex MCNormal MCTangent TexCoord0 What you see on the pixelFragColor LightDir EyeDir TexCoord Vertex Shader Fragment Shader

7. Vertex Shader • compute the informaion of vertices gl_Position = MVPMatrix * MCVertex; EyeDir = vec3(MVMatrix * MCVertex); TexCoord = TexCoord0.st; vec3 n = normalize(NormalMatrix * MCNormal); vec3 t = normalize(NormalMatrix * MCTangent); vec3 b = cross(n, t); vec3 v; v.x = dot(LightPosition, t); v.y = dot(LightPosition, b); v.z = dot(LightPosition, n); LightDir = normalize(v); v.x = dot(EyeDir, t); v.y = dot(EyeDir, b); v.z = dot(EyeDir, n); EyeDir = normalize(v);

8. Fragment Shader • calculate the color to be perceived vec3 litColor; vec2 c = BumpDensity * TexCoord.st; vec2 p = fract(c) - vec2(0.5); float d, f; d = dot(p,p); f = inversesqrt(d + 1.0); if (d >= BumpSize) { p = vec2(0.0); f = 1.0; } vec3 normDelta = vec3(p.x, p.y, 1.0) * f; litColor = SurfaceColor.rgb * max(dot(normDelta, LightDir), 0.0); vec3 reflectDir = reflect(LightDir, normDelta); float spec = max(dot(EyeDir, reflectDir), 0.0); spec = pow(spec, 6.0); spec *= SpecularFactor; litColor = min(litColor+spec,vec3(1.0)); FragColor = vec4(litColor, SurfaceColor.a);

9. Bump Map • height map • normal map • displacement map height / normal displacement

10. Create Bump Map • Image Editing Software • Photoshop • PhotoImpact • GIMP • CrazyBump http://www.crazybump.com/

11. Create Bump Map • get a image of the texture • take a photo by yourself • find images on the Internet http://www.cgtextures.com/

12. Create Bump Map

13. Create Bump Map • select bumps or dents

14. Create Bump Map • adjust parameters and save 1. 2.

15. Create Bump Map Normal Grayscale of Normal convert by other software Occlusion Specularity

16. Create Bump Map Without Bump Map Specularityas Height Map