1 files changed, 65 insertions, 0 deletions
diff --git a/src/modules/ray/ray_object_sphere.h b/src/modules/ray/ray_object_sphere.h
new file mode 100644
index 0000000..85b3d93
--- /dev/null
+++ b/src/modules/ray/ray_object_sphere.h
@@ -0,0 +1,65 @@
+#ifndef _RAY_OBJECT_SPHERE_H
+#define _RAY_OBJECT_SPHERE_H
+
+#include <math.h>
+#include <stdio.h>
+
+#include "ray_3f.h"
+#include "ray_color.h"
+#include "ray_object_type.h"
+#include "ray_ray.h"
+#include "ray_surface.h"
+
+
+typedef struct ray_object_sphere_t {
+	ray_object_type_t	type;
+	ray_surface_t		surface;
+	ray_3f_t		center;
+	float			radius;
+} ray_object_sphere_t;
+
+
+static inline int ray_object_sphere_intersects_ray(ray_object_sphere_t *sphere, ray_ray_t *ray, float *res_distance)
+{
+	ray_3f_t	v = ray_3f_sub(&ray->origin, &sphere->center);
+	float		b = ray_3f_dot(&v, &ray->direction);
+	float		disc = (sphere->radius * sphere->radius) - ray_3f_dot(&v, &v) + (b * b);
+
+	if (disc > 0) {
+		float	i1, i2;
+
+		disc = sqrtf(disc);
+
+		i1 = b - disc;
+		i2 = b + disc;
+
+		if (i2 > 0 && i1 > 0) {
+			*res_distance = i1;
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+
+/* return the normal of the surface at the specified point */
+static inline ray_3f_t ray_object_sphere_normal(ray_object_sphere_t *sphere, ray_3f_t *point)
+{
+	ray_3f_t	normal;
+	
+	normal = ray_3f_sub(point, &sphere->center);
+	normal = ray_3f_div_scalar(&normal, sphere->radius);	/* normalize without the sqrt() */
+
+	return normal;
+}
+
+
+/* return the surface of the sphere @ point */
+static inline ray_surface_t ray_object_sphere_surface(ray_object_sphere_t *sphere, ray_3f_t *point)
+{
+	/* uniform solids for now... */
+	return sphere->surface;
+}
+
+#endif