1 #include "tgi_impl.h"

2 #include "shape.h"

3

4 static int ray_sphere_intersect(struct tgi_shape *shape, ray_t ray, struct tgi_hitpoint *hit);

5 static int ray_box_intersect(struct tgi_shape *shape, ray_t ray, struct tgi_hitpoint *hit);

6

7 struct tgi_shape *tgi_create_sphere(float x, float y, float z, float rad)

8 {

9 struct tgi_shape *shape;

10 struct tgi_sphere_data *sphere;

11

12 if(!(shape = malloc(sizeof *shape)) || !(sphere = malloc(sizeof *sphere))) {

13 free(shape);

14 tgi_log("failed to allocate sphere shape\n");

15 return 0;

16 }

17 shape->data = sphere;

18 shape->obj = 0;

19 shape->intersect = ray_sphere_intersect;

20

21 sphere->pos.x = x;

22 sphere->pos.y = y;

23 sphere->pos.z = z;

24 sphere->rad = rad;

25 return shape;

26 }

27

28 struct tgi_shape *tgi_create_box(float x0, float y0, float z0, float x1, float y1, float z1)

29 {

30 return 0; /* TODO */

31 }

32

33 void tgi_destroy_shape(struct tgi_shape *s)

34 {

35 if(s) {

36 if(s->obj) {

37 s->obj->shape = 0;

38 }

39 free(s->data);

40 free(s);

41 }

42 }

43

44 static int ray_sphere_intersect(struct tgi_shape *shape, ray_t ray, struct tgi_hitpoint *hit)

45 {

46 float x0, x1, t;

47 struct tgi_sphere_data *sph = shape->data;

48 ray_t oray = ray_transform(ray, shape->obj->inv_xform);

49

50 float a = v3_dot(oray.dir, oray.dir);

51 float b = 2.0 * oray.dir.x * (oray.origin.x - sph->pos.x) +

52 2.0 * oray.dir.y * (oray.origin.y - sph->pos.y) +

53 2.0 * oray.dir.z * (oray.origin.z - sph->pos.z);

54 float c = v3_dot(oray.origin, oray.origin) + v3_dot(sph->pos, sph->pos) -

55 2.0 * v3_dot(oray.origin, sph->pos) - sph->rad * sph->rad;

56

57 float disc = b * b - 4.0 * a * c;

58 if(disc < 0.0) {

59 return 0;

60 }

61

62 x0 = (-b + sqrt(disc)) / (2.0 * a);

63 x1 = (-b - sqrt(disc)) / (2.0 * a);

64

65 if(x0 < 1e-5) x0 = x1;

66 if(x1 < 1e-5) x1 = x0;

67

68 t = x0 < x1 ? x0 : x1;

69 if(t < 1e-5) {

70 return 0;

71 }

72

73 if(hit) {

74 vec3_t gcent = v3_transform(sph->pos, shape->obj->xform);

75

76 hit->t = t;

77 hit->ray = ray;

78 hit->local_ray = oray;

79 hit->pos = v3_scale(v3_add(ray.origin, ray.dir), t);

80 hit->norm = v3_scale(v3_sub(hit->pos, gcent), 1.0 / sph->rad);

81 hit->uv.x = atan2(hit->norm.z, hit->norm.x);

82 hit->uv.y = acos(hit->norm.y);

83 }

84 return 1;

85 }

86

87 static int ray_box_intersect(struct tgi_shape *shape, ray_t ray, struct tgi_hitpoint *hit)

88 {

89 return 0;

90 }

91