ray: move shadow check to a function

Just tidying up shade_ray() before more optimizations.

1 files changed, 21 insertions, 10 deletions

diff --git a/src/modules/ray/ray_scene.c b/src/modules/ray/ray_scene.c
index 955bab6..eb18d08 100644
--- a/src/modules/ray/ray_scene.c
+++ b/src/modules/ray/ray_scene.c
@@ -36,6 +36,26 @@ static inline int ray_is_obstructed(ray_scene_t *scene, ray_ray_t *ray, float di
 }
 
 
+/* shadow test */
+static inline int point_is_shadowed(ray_scene_t *scene, ray_3f_t *light_direction, float distance, ray_3f_t *point)
+{
+	ray_ray_t	shadow_ray;
+
+	/* negate the light vector so it's pointed at the light rather than from it */
+	shadow_ray.direction = ray_3f_negate(light_direction);
+
+	/* we must shift the origin slightly (epsilon) towards the light to
+	 * prevent spurious self-obstruction at the ray:object intersection */
+	shadow_ray.origin = ray_3f_mult_scalar(&shadow_ray.direction, 0.00001f);
+	shadow_ray.origin = ray_3f_add(&shadow_ray.origin, point);
+
+	if (ray_is_obstructed(scene, &shadow_ray, distance))
+		return 1;
+
+	return 0;
+}
+
+
 /* a faster powf() that's good enough for our purposes.
  * XXX: note there's a faster technique which exploits the IEEE floating point format:
  * https://github.com/ekmett/approximate/blob/master/cbits/fast.c#L185
@@ -64,19 +84,10 @@ static inline ray_color_t shade_ray(ray_scene_t *scene, ray_ray_t *ray, ray_obje
 		ray_3f_t	lvec = ray_3f_sub(&scene->lights[i].light.emitter.point.center, &intersection);
 		float		ldist = ray_3f_length(&lvec);
 		float		lvec_normal_dot;
-		ray_ray_t	shadow_ray;
 
 		lvec = ray_3f_mult_scalar(&lvec, (1.0f / ldist)); /* normalize lvec */
 #if 1
-		/* skip this light if it's obstructed,
-		 * we must shift the origin slightly towards the light to prevent
-		 * spurious self-obstruction at the ray:object intersection */
-		/* negate the light vector so it's pointed at the light rather than from it */
-		shadow_ray.direction = ray_3f_negate(&lvec);
-		shadow_ray.origin = ray_3f_mult_scalar(&shadow_ray.direction, 0.00001f);
-		shadow_ray.origin = ray_3f_add(&shadow_ray.origin, &intersection);
-
-		if (ray_is_obstructed(scene, &shadow_ray, ldist))
+		if (point_is_shadowed(scene, &lvec, ldist, &intersection))
 			continue;
 #endif
 		lvec_normal_dot = ray_3f_dot(&normal, &lvec);