From 3206fc10cb2cf01e61232a04f68917b0c244e552 Mon Sep 17 00:00:00 2001 From: Vito Caputo Date: Sat, 3 Jun 2017 23:48:44 -0700 Subject: ray: convert from recursive to iterative tracing Small speedup, I personally find the code cleaner this way too. Everything in the hot path should now be inlined, no function calls. --- src/modules/ray/ray_object_plane.h | 2 +- src/modules/ray/ray_object_sphere.h | 2 +- src/modules/ray/ray_scene.c | 97 ++++++++++++++++++++++--------------- 3 files changed, 60 insertions(+), 41 deletions(-) diff --git a/src/modules/ray/ray_object_plane.h b/src/modules/ray/ray_object_plane.h index 5fcc619..490238c 100644 --- a/src/modules/ray/ray_object_plane.h +++ b/src/modules/ray/ray_object_plane.h @@ -32,7 +32,7 @@ static inline int ray_object_plane_intersects_ray(ray_object_plane_t *plane, uns if (d >= 0.00001f) { float distance = plane->_prepared.primary_dot_plus; - if (depth != 1) + if (depth) distance = (ray_3f_dot(&plane->normal, &ray->origin) + plane->distance); distance /= d; diff --git a/src/modules/ray/ray_object_sphere.h b/src/modules/ray/ray_object_sphere.h index 1eb37e8..c07f345 100644 --- a/src/modules/ray/ray_object_sphere.h +++ b/src/modules/ray/ray_object_sphere.h @@ -43,7 +43,7 @@ static inline int ray_object_sphere_intersects_ray(ray_object_sphere_t *sphere, float dot_vv = sphere->_prepared.primary_dot_vv; float b, disc; - if (depth != 1) { + if (depth) { v = ray_3f_sub(&ray->origin, &sphere->center); dot_vv = ray_3f_dot(&v, &v); } diff --git a/src/modules/ray/ray_scene.c b/src/modules/ray/ray_scene.c index 2df4a5d..2ad7f99 100644 --- a/src/modules/ray/ray_scene.c +++ b/src/modules/ray/ray_scene.c @@ -12,8 +12,6 @@ #define MAX_RECURSION_DEPTH 4 -static ray_color_t trace_ray(ray_scene_t *scene, ray_object_t *reflector, ray_ray_t *ray, unsigned depth); - /* Determine if the ray is obstructed by an object within the supplied distance, for shadows */ static inline int ray_is_obstructed(ray_scene_t *scene, unsigned depth, ray_ray_t *ray, float distance) @@ -64,30 +62,24 @@ static inline float approx_powf(float x, float y) /* Determine the color @ distance on ray on object viewed from origin */ -static inline ray_color_t shade_ray(ray_scene_t *scene, ray_ray_t *ray, ray_object_t *object, float distance, unsigned depth) +static inline ray_color_t shade_intersection(ray_scene_t *scene, ray_object_t *object, ray_ray_t *ray, ray_3f_t *intersection, ray_3f_t *normal, unsigned depth, float *res_reflectivity) { - ray_surface_t surface; - ray_color_t color; - ray_3f_t rvec = ray_3f_mult_scalar(&ray->direction, distance); - ray_3f_t intersection = ray_3f_sub(&ray->origin, &rvec); - ray_3f_t normal = ray_object_normal(object, &intersection); + ray_surface_t surface = ray_object_surface(object, intersection); + ray_color_t color = ray_3f_mult(&surface.color, &scene->_prepared.ambient_light); unsigned i; - surface = ray_object_surface(object, &intersection); - color = ray_3f_mult(&surface.color, &scene->_prepared.ambient_light); - /* visit lights for shadows and illumination */ for (i = 0; i < scene->n_lights; i++) { - ray_3f_t lvec = ray_3f_sub(&scene->lights[i].light.emitter.point.center, &intersection); + 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; lvec = ray_3f_mult_scalar(&lvec, (1.0f / ldist)); /* normalize lvec */ #if 1 - if (point_is_shadowed(scene, depth, &lvec, ldist, &intersection)) + if (point_is_shadowed(scene, depth, &lvec, ldist, intersection)) continue; #endif - lvec_normal_dot = ray_3f_dot(&normal, &lvec); + lvec_normal_dot = ray_3f_dot(normal, &lvec); if (lvec_normal_dot > 0) { #if 1 @@ -114,37 +106,19 @@ static inline ray_color_t shade_ray(ray_scene_t *scene, ray_ray_t *ray, ray_obje } } - /* generate a reflection ray */ -#if 1 - if (depth < MAX_RECURSION_DEPTH) { - float dot = ray_3f_dot(&ray->direction, &normal); - ray_ray_t reflected_ray = { .direction = ray_3f_mult_scalar(&normal, dot * 2.0f) }; - ray_3f_t reflection; - - reflected_ray.origin = intersection; - reflected_ray.direction = ray_3f_sub(&ray->direction, &reflected_ray.direction); - - reflection = trace_ray(scene, object, &reflected_ray, depth); - reflection = ray_3f_mult_scalar(&reflection, surface.specular); - color = ray_3f_add(&color, &reflection); - } -#endif - - /* TODO: generate a refraction ray */ + /* for now just treat specular as the reflectivity */ + *res_reflectivity = surface.specular; return color; } -static ray_color_t trace_ray(ray_scene_t *scene, ray_object_t *reflector, ray_ray_t *ray, unsigned depth) +static inline ray_object_t * find_nearest_intersection(ray_scene_t *scene, ray_object_t *reflector, ray_ray_t *ray, unsigned depth, float *res_distance) { ray_object_t *nearest_object = NULL; float nearest_object_distance = INFINITY; - ray_color_t color = { .x = 0.0, .y = 0.0, .z = 0.0 }; unsigned i; - depth++; - for (i = 0; i < scene->n_objects; i++) { ray_object_t *object = &scene->objects[i]; float distance; @@ -156,7 +130,6 @@ static ray_color_t trace_ray(ray_scene_t *scene, ray_object_t *reflector, ray_ra /* Does this ray intersect object? */ if (ray_object_intersects_ray(object, depth, ray, &distance)) { - /* Is it the nearest intersection? */ if (distance < nearest_object_distance) { nearest_object = object; @@ -166,9 +139,55 @@ static ray_color_t trace_ray(ray_scene_t *scene, ray_object_t *reflector, ray_ra } if (nearest_object) - color = shade_ray(scene, ray, nearest_object, nearest_object_distance, depth); + *res_distance = nearest_object_distance; + + return nearest_object; +} + + +static inline ray_color_t trace_ray(ray_scene_t *scene, ray_ray_t *primary_ray) +{ + ray_color_t color = { .x = 0.0f, .y = 0.0f, .z = 0.0f }; + ray_3f_t intersection, normal; + ray_object_t *reflector = NULL; + float relevance = 1.0f, reflectivity; + unsigned depth = 0; + ray_ray_t reflected_ray, *ray = primary_ray; + + do { + ray_object_t *nearest_object; + float nearest_distance; + + if (reflector) { + float dot = ray_3f_dot(&ray->direction, &normal); + ray_3f_t new_direction = ray_3f_mult_scalar(&normal, dot * 2.0f); + + new_direction = ray_3f_sub(&ray->direction, &new_direction); + + reflected_ray.origin = intersection; + reflected_ray.direction = new_direction; + + ray = &reflected_ray; + + relevance *= reflectivity; + } + + nearest_object = find_nearest_intersection(scene, reflector, ray, depth, &nearest_distance); + if (nearest_object) { + ray_3f_t more_color; + ray_3f_t rvec; + + rvec = ray_3f_mult_scalar(&ray->direction, nearest_distance); + intersection = ray_3f_sub(&ray->origin, &rvec); + normal = ray_object_normal(nearest_object, &intersection); + + more_color = shade_intersection(scene, nearest_object, ray, &intersection, &normal, depth, &reflectivity); + more_color = ray_3f_mult_scalar(&more_color, relevance); + color = ray_3f_add(&color, &more_color); + } - depth--; + reflector = nearest_object; + } while (reflector && (++depth < MAX_RECURSION_DEPTH)); return color; } @@ -184,7 +203,7 @@ void ray_scene_render_fragment(ray_scene_t *scene, ray_camera_t *camera, fb_frag ray_camera_frame_begin(camera, fragment, &ray, &frame); do { do { - *buf = ray_color_to_uint32_rgb(trace_ray(scene, NULL, &ray, 0)); + *buf = ray_color_to_uint32_rgb(trace_ray(scene, &ray)); buf++; } while (ray_camera_frame_x_step(&frame)); -- cgit v1.2.3