tesspot

annotate sdr/bezier.te.glsl @ 0:72b7f9f2eead

initial commit
author John Tsiombikas <nuclear@member.fsf.org>
date Sun, 02 Dec 2012 08:23:51 +0200
parents
children befe01bbd27f
rev   line source
nuclear@0 1 #version 410 compatibility
nuclear@0 2
nuclear@0 3 layout(quads) in;
nuclear@0 4
nuclear@0 5 out vec3 normal;
nuclear@0 6 out vec3 vpos;
nuclear@0 7
nuclear@0 8 vec3 bezier_patch(float u, float v);
nuclear@0 9 vec3 bezier_patch_norm(float u, float v);
nuclear@0 10 float bernstein(int i, float x);
nuclear@0 11
nuclear@0 12 void main()
nuclear@0 13 {
nuclear@0 14 vec3 pos = bezier_patch(gl_TessCoord.x, gl_TessCoord.y);
nuclear@0 15 normal = gl_NormalMatrix * bezier_patch_norm(gl_TessCoord.x, gl_TessCoord.y);
nuclear@0 16
nuclear@0 17 gl_Position = gl_ModelViewProjectionMatrix * vec4(pos, 1.0);
nuclear@0 18 vpos = (gl_ModelViewMatrix * vec4(pos, 1.0)).xyz;
nuclear@0 19 }
nuclear@0 20
nuclear@0 21 vec3 bezier_patch(float u, float v)
nuclear@0 22 {
nuclear@0 23 int i, j;
nuclear@0 24 vec3 res = vec3(0.0, 0.0, 0.0);
nuclear@0 25
nuclear@0 26 for(j=0; j<4; j++) {
nuclear@0 27 for(i=0; i<4; i++) {
nuclear@0 28 float bu = bernstein(i, u);
nuclear@0 29 float bv = bernstein(j, v);
nuclear@0 30
nuclear@0 31 res += gl_in[j * 4 + i].gl_Position.xyz * bu * bv;
nuclear@0 32 }
nuclear@0 33 }
nuclear@0 34 return res;
nuclear@0 35 }
nuclear@0 36
nuclear@0 37 #define DT 0.0001
nuclear@0 38 vec3 bezier_patch_norm(float u, float v)
nuclear@0 39 {
nuclear@0 40 vec3 tang = bezier_patch(u + DT, v) - bezier_patch(u - DT, v);
nuclear@0 41 vec3 bitan = bezier_patch(u, v + DT) - bezier_patch(u, v - DT);
nuclear@0 42 return cross(tang, bitan);
nuclear@0 43 }
nuclear@0 44
nuclear@0 45 float bernstein(int i, float x)
nuclear@0 46 {
nuclear@0 47 float invx = 1.0 - x;
nuclear@0 48
nuclear@0 49 if(i == 0) {
nuclear@0 50 return invx * invx * invx;
nuclear@0 51 }
nuclear@0 52 if(i == 1) {
nuclear@0 53 return 3 * x * invx * invx;
nuclear@0 54 }
nuclear@0 55 if(i == 2) {
nuclear@0 56 return 3 * x * x * invx;
nuclear@0 57 }
nuclear@0 58 return x * x * x;
nuclear@0 59 }