tesspot
annotate sdr/bezier.te.glsl @ 2:178a9e3c3c8c
isolines
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Mon, 03 Dec 2012 07:30:39 +0200 |
| parents | befe01bbd27f |
| children |
| rev | line source |
|---|---|
| nuclear@0 | 1 #version 410 compatibility |
| nuclear@0 | 2 |
| nuclear@1 | 3 layout(quads, ccw) in; |
| nuclear@0 | 4 |
| nuclear@0 | 5 out vec3 normal; |
| nuclear@0 | 6 out vec3 vpos; |
| nuclear@2 | 7 out vec2 uv; |
| nuclear@0 | 8 |
| nuclear@1 | 9 uniform vec3 norm_scale; |
| nuclear@1 | 10 |
| nuclear@0 | 11 vec3 bezier_patch(float u, float v); |
| nuclear@0 | 12 vec3 bezier_patch_norm(float u, float v); |
| nuclear@0 | 13 float bernstein(int i, float x); |
| nuclear@0 | 14 |
| nuclear@0 | 15 void main() |
| nuclear@0 | 16 { |
| nuclear@0 | 17 vec3 pos = bezier_patch(gl_TessCoord.x, gl_TessCoord.y); |
| nuclear@0 | 18 normal = gl_NormalMatrix * bezier_patch_norm(gl_TessCoord.x, gl_TessCoord.y); |
| nuclear@0 | 19 |
| nuclear@2 | 20 uv = gl_TessCoord.xy; |
| nuclear@2 | 21 |
| nuclear@0 | 22 gl_Position = gl_ModelViewProjectionMatrix * vec4(pos, 1.0); |
| nuclear@0 | 23 vpos = (gl_ModelViewMatrix * vec4(pos, 1.0)).xyz; |
| nuclear@0 | 24 } |
| nuclear@0 | 25 |
| nuclear@0 | 26 vec3 bezier_patch(float u, float v) |
| nuclear@0 | 27 { |
| nuclear@0 | 28 int i, j; |
| nuclear@0 | 29 vec3 res = vec3(0.0, 0.0, 0.0); |
| nuclear@0 | 30 |
| nuclear@0 | 31 for(j=0; j<4; j++) { |
| nuclear@0 | 32 for(i=0; i<4; i++) { |
| nuclear@0 | 33 float bu = bernstein(i, u); |
| nuclear@0 | 34 float bv = bernstein(j, v); |
| nuclear@0 | 35 |
| nuclear@0 | 36 res += gl_in[j * 4 + i].gl_Position.xyz * bu * bv; |
| nuclear@0 | 37 } |
| nuclear@0 | 38 } |
| nuclear@0 | 39 return res; |
| nuclear@0 | 40 } |
| nuclear@0 | 41 |
| nuclear@0 | 42 #define DT 0.0001 |
| nuclear@0 | 43 vec3 bezier_patch_norm(float u, float v) |
| nuclear@0 | 44 { |
| nuclear@0 | 45 vec3 tang = bezier_patch(u + DT, v) - bezier_patch(u - DT, v); |
| nuclear@0 | 46 vec3 bitan = bezier_patch(u, v + DT) - bezier_patch(u, v - DT); |
| nuclear@1 | 47 return cross(tang, bitan) * norm_scale; |
| nuclear@0 | 48 } |
| nuclear@0 | 49 |
| nuclear@0 | 50 float bernstein(int i, float x) |
| nuclear@0 | 51 { |
| nuclear@0 | 52 float invx = 1.0 - x; |
| nuclear@0 | 53 |
| nuclear@0 | 54 if(i == 0) { |
| nuclear@0 | 55 return invx * invx * invx; |
| nuclear@0 | 56 } |
| nuclear@0 | 57 if(i == 1) { |
| nuclear@0 | 58 return 3 * x * invx * invx; |
| nuclear@0 | 59 } |
| nuclear@0 | 60 if(i == 2) { |
| nuclear@0 | 61 return 3 * x * x * invx; |
| nuclear@0 | 62 } |
| nuclear@0 | 63 return x * x * x; |
| nuclear@0 | 64 } |