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annotate src/teapot.c @ 3:316ec8250af2

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added the teapot code for testing
author John Tsiombikas <nuclear@member.fsf.org>
date Thu, 25 Sep 2014 17:13:23 +0300
parents
children 053a52f0cb64
rev   line source
nuclear@3 1 #ifndef __APPLE__
nuclear@3 2 #include <GL/gl.h>
nuclear@3 3 #else
nuclear@3 4 #include <OpenGL/gl.h>
nuclear@3 5 #endif
nuclear@3 6
nuclear@3 7 #include "teapot.h"
nuclear@3 8 #include "teapot_data.h"
nuclear@3 9
nuclear@3 10 static void draw_patch(struct vec3 *bez_cp, int *index, int flip, int useg, int vseg, float scale);
nuclear@3 11
nuclear@3 12 int patch_subdivision = 6;
nuclear@3 13
nuclear@3 14 void bezier_teapot(float scale)
nuclear@3 15 {
nuclear@3 16 int i;
nuclear@3 17
nuclear@3 18 scale /= 2.0;
nuclear@3 19
nuclear@3 20 for(i=0; i<NUM_TEAPOT_PATCHES; i++) {
nuclear@3 21 float flip = teapot_part_flip[i];
nuclear@3 22 float rot = teapot_part_rot[i];
nuclear@3 23
nuclear@3 24 glMatrixMode(GL_MODELVIEW);
nuclear@3 25 glPushMatrix();
nuclear@3 26 glTranslatef(0, -3.15 * scale * 0.5, 0);
nuclear@3 27 glRotatef(rot, 0, 1, 0);
nuclear@3 28 glScalef(1, 1, flip);
nuclear@3 29 glRotatef(-90, 1, 0, 0);
nuclear@3 30
nuclear@3 31 draw_patch(teapot_verts, teapot_index + i * 16, flip < 0.0 ? 1 : 0, patch_subdivision, patch_subdivision, scale);
nuclear@3 32
nuclear@3 33 glPopMatrix();
nuclear@3 34 }
nuclear@3 35 }
nuclear@3 36
nuclear@3 37 static void draw_patch(struct vec3 *bez_cp, int *index, int flip, int useg, int vseg, float scale)
nuclear@3 38 {
nuclear@3 39 static const float uoffs[2][4] = {{0, 0, 1, 1}, {1, 1, 0, 0}};
nuclear@3 40 static const float voffs[4] = {0, 1, 1, 0};
nuclear@3 41
nuclear@3 42 int i, j, k;
nuclear@3 43 struct vec3 cp[16];
nuclear@3 44 struct vec3 pt, n;
nuclear@3 45 float u, v;
nuclear@3 46 float du = 1.0 / useg;
nuclear@3 47 float dv = 1.0 / vseg;
nuclear@3 48
nuclear@3 49 /* collect control points */
nuclear@3 50 for(i=0; i<16; i++) {
nuclear@3 51 cp[i] = bez_cp[index[i]];
nuclear@3 52 }
nuclear@3 53
nuclear@3 54 glBegin(GL_QUADS);
nuclear@3 55 glColor3f(1, 1, 1);
nuclear@3 56
nuclear@3 57 u = 0;
nuclear@3 58 for(i=0; i<useg; i++) {
nuclear@3 59 v = 0;
nuclear@3 60 for(j=0; j<vseg; j++) {
nuclear@3 61
nuclear@3 62 for(k=0; k<4; k++) {
nuclear@3 63 pt = bezier_patch(cp, u + uoffs[flip][k] * du, v + voffs[k] * dv);
nuclear@3 64
nuclear@3 65 /* top/bottom normal hack */
nuclear@3 66 if(pt.z > 3.14) {
nuclear@3 67 n.x = n.y = 0.0f;
nuclear@3 68 n.z = 1.0f;
nuclear@3 69 } else if(pt.z < 0.00001) {
nuclear@3 70 n.x = n.y = 0.0f;
nuclear@3 71 n.z = -1.0f;
nuclear@3 72 } else {
nuclear@3 73 n = bezier_patch_norm(cp, u + uoffs[flip][k] * du, v + voffs[k] * dv);
nuclear@3 74 }
nuclear@3 75
nuclear@3 76 glTexCoord2f(u, v);
nuclear@3 77 glNormal3f(n.x, n.y, n.z);
nuclear@3 78 glVertex3f(pt.x * scale, pt.y * scale, pt.z * scale);
nuclear@3 79 }
nuclear@3 80
nuclear@3 81 v += dv;
nuclear@3 82 }
nuclear@3 83 u += du;
nuclear@3 84 }
nuclear@3 85
nuclear@3 86 glEnd();
nuclear@3 87 }