1 #ifndef __APPLE__

2 #include <GL/gl.h>

3 #else

4 #include <OpenGL/gl.h>

5 #endif

6

7 #include "teapot.h"

8 #include "teapot_data.h"

9

10 static void draw_patch(struct vec3 *bez_cp, int *index, int flip, int useg, int vseg, float scale);

11

12 int patch_subdivision = 6;

13

14 void bezier_teapot(float scale)

15 {

16 int i;

17

18 scale /= 2.0;

19

20 for(i=0; i<NUM_TEAPOT_PATCHES; i++) {

21 float flip = teapot_part_flip[i];

22 float rot = teapot_part_rot[i];

23

24 glMatrixMode(GL_MODELVIEW);

25 glPushMatrix();

26 glTranslatef(0, -3.15 * scale * 0.5, 0);

27 glRotatef(rot, 0, 1, 0);

28 glScalef(1, 1, flip);

29 glRotatef(-90, 1, 0, 0);

30

31 draw_patch(teapot_verts, teapot_index + i * 16, flip < 0.0 ? 1 : 0, patch_subdivision, patch_subdivision, scale);

32

33 glPopMatrix();

34 }

35 }

36

37 static void draw_patch(struct vec3 *bez_cp, int *index, int flip, int useg, int vseg, float scale)

38 {

39 static const float uoffs[2][4] = {{0, 0, 1, 1}, {1, 1, 0, 0}};

40 static const float voffs[4] = {0, 1, 1, 0};

41

42 int i, j, k;

43 struct vec3 cp[16];

44 struct vec3 pt, n;

45 float u, v;

46 float du = 1.0 / useg;

47 float dv = 1.0 / vseg;

48

49 /* collect control points */

50 for(i=0; i<16; i++) {

51 cp[i] = bez_cp[index[i]];

52 }

53

54 glBegin(GL_QUADS);

55 glColor3f(1, 1, 1);

56

57 u = 0;

58 for(i=0; i<useg; i++) {

59 v = 0;

60 for(j=0; j<vseg; j++) {

61

62 for(k=0; k<4; k++) {

63 pt = bezier_patch(cp, u + uoffs[flip][k] * du, v + voffs[k] * dv);

64

65 /* top/bottom normal hack */

66 if(pt.z > 3.14) {

67 n.x = n.y = 0.0f;

68 n.z = 1.0f;

69 } else if(pt.z < 0.00001) {

70 n.x = n.y = 0.0f;

71 n.z = -1.0f;

72 } else {

73 n = bezier_patch_norm(cp, u + uoffs[flip][k] * du, v + voffs[k] * dv);

74 }

75

76 glTexCoord2f(u, v);

77 glNormal3f(n.x, n.y, n.z);

78 glVertex3f(pt.x * scale, pt.y * scale, pt.z * scale);

79 }

80

81 v += dv;

82 }

83 u += du;

84 }

85

86 glEnd();

87 }