diff options
Diffstat (limited to 'libdimension')
| -rw-r--r-- | libdimension/raytrace.c | 137 |
1 files changed, 81 insertions, 56 deletions
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c index 4d99498..143c2bc 100644 --- a/libdimension/raytrace.c +++ b/libdimension/raytrace.c @@ -22,6 +22,10 @@ #include <unistd.h> /* For sysconf */ #include <stdbool.h> +/* + * Boilerplate for multithreading + */ + /* Payload type for passing arguments to worker thread */ typedef struct { @@ -207,14 +211,16 @@ dmnsn_raytrace_scene_multithread_thread(void *ptr) return retval; } -/* Helper for dmnsn_raytrace_scene_impl - shoot a ray */ +/* + * Raytracing algorithm + */ + +/* Main helper for dmnsn_raytrace_scene_impl - shoot a ray */ static dmnsn_color dmnsn_raytrace_shoot(dmnsn_line ray, dmnsn_scene *scene, dmnsn_kD_splay_tree *kD_splay_tree, dmnsn_color color); -/* - * Actually raytrace a scene - */ +/* Actually raytrace a scene */ static int dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene, dmnsn_kD_splay_tree *kD_splay_tree, @@ -252,7 +258,17 @@ dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene, return 0; } -static const double epsilon = 1.0e-9; +static dmnsn_line +dmnsn_line_add_epsilon(dmnsn_line l) +{ + return dmnsn_line_construct( + dmnsn_vector_add( + l.x0, + dmnsn_vector_mul(1.0e-9, l.n) + ), + l.n + ); +} static dmnsn_color dmnsn_raytrace_pigment(dmnsn_intersection *intersection, dmnsn_scene *scene) @@ -281,6 +297,55 @@ dmnsn_raytrace_pigment(dmnsn_intersection *intersection, dmnsn_scene *scene) return color; } +/* Get the color of a light ray at an intersection point */ +static bool +dmnsn_raytrace_light_ray(dmnsn_intersection *intersection, dmnsn_scene *scene, + dmnsn_kD_splay_tree *kD_splay_tree, + const dmnsn_light *light, dmnsn_color *color) +{ + *color = dmnsn_black; + + dmnsn_vector x0 = dmnsn_line_point(intersection->ray, intersection->t); + dmnsn_line shadow_ray = dmnsn_line_construct( + x0, + dmnsn_vector_sub(light->x0, x0) + ); + /* Add epsilon to avoid hitting ourselves with the shadow ray */ + shadow_ray = dmnsn_line_add_epsilon(shadow_ray); + + /* Search for an object in the way of the light source */ + if (dmnsn_vector_dot(shadow_ray.n, intersection->normal) < 0.0) + return false; + + *color = (*light->light_fn)(light, x0); + + dmnsn_intersection *shadow_caster; + while (1) { + shadow_caster = dmnsn_kD_splay_search(kD_splay_tree, shadow_ray); + + if (!shadow_caster || shadow_caster->t > 1.0) { + dmnsn_delete_intersection(shadow_caster); + break; + } + + dmnsn_color pigment = dmnsn_raytrace_pigment(shadow_caster, scene); + if (pigment.filter || pigment.trans) { + *color = dmnsn_color_filter(*color, pigment); + shadow_ray.x0 = dmnsn_line_point(shadow_ray, shadow_caster->t); + shadow_ray.n = dmnsn_vector_sub(light->x0, shadow_ray.x0); + shadow_ray = dmnsn_line_add_epsilon(shadow_ray); + } else { + *color = dmnsn_black; + dmnsn_delete_intersection(shadow_caster); + return false; + } + + dmnsn_delete_intersection(shadow_caster); + } + + return true; +} + static dmnsn_color dmnsn_raytrace_lighting(dmnsn_intersection *intersection, dmnsn_scene *scene, dmnsn_kD_splay_tree *kD_splay_tree, dmnsn_color color) @@ -300,60 +365,23 @@ dmnsn_raytrace_lighting(dmnsn_intersection *intersection, dmnsn_scene *scene, if (finish) illum = dmnsn_color_mul(finish->ambient, color); + dmnsn_vector x0 = dmnsn_line_point(intersection->ray, intersection->t); + const dmnsn_light *light; unsigned int i; + /* Iterate over each light */ for (i = 0; i < dmnsn_array_size(scene->lights); ++i) { dmnsn_array_get(scene->lights, i, &light); - dmnsn_vector x0 = dmnsn_line_point(intersection->ray, intersection->t); - dmnsn_line shadow_ray = dmnsn_line_construct( - /* Add epsilon*(light->x0 - x0) to avoid hitting ourself with the shadow - ray */ - dmnsn_vector_add( - x0, - dmnsn_vector_mul(epsilon, dmnsn_vector_sub(light->x0, x0)) - ), - dmnsn_vector_sub(light->x0, x0) - ); - - /* Search for an object in the way of the light source */ dmnsn_color light_color; - bool lit = false; - if (dmnsn_vector_dot(shadow_ray.n, intersection->normal) > 0.0) { - lit = true; - light_color = (*light->light_fn)(light, x0); - - dmnsn_intersection *shadow_caster; - while (1) { - shadow_caster = dmnsn_kD_splay_search(kD_splay_tree, shadow_ray); - - if (!shadow_caster || shadow_caster->t > 1.0) { - dmnsn_delete_intersection(shadow_caster); - break; - } - - dmnsn_color pigment = dmnsn_raytrace_pigment(shadow_caster, scene); - if (pigment.filter || pigment.trans) { - light_color = dmnsn_color_filter(light_color, pigment); - shadow_ray.x0 = dmnsn_vector_add( - dmnsn_line_point(shadow_ray, shadow_caster->t), - dmnsn_vector_mul(epsilon, shadow_ray.n) - ); - shadow_ray.n = dmnsn_vector_sub(light->x0, shadow_ray.x0); - } else { - lit = false; - dmnsn_delete_intersection(shadow_caster); - break; - } - - dmnsn_delete_intersection(shadow_caster); - } - } - - if (lit) { + if (dmnsn_raytrace_light_ray(intersection, scene, kD_splay_tree, light, + &light_color)) + { if (scene->quality >= DMNSN_RENDER_FINISH && finish) { - dmnsn_vector ray = dmnsn_vector_normalize(shadow_ray.n); + dmnsn_vector ray = dmnsn_vector_normalize( + dmnsn_vector_sub(light->x0, x0) + ); dmnsn_vector normal = intersection->normal; dmnsn_vector viewer = dmnsn_vector_normalize(dmnsn_vector_negate(intersection->ray.n)); @@ -412,13 +440,10 @@ dmnsn_raytrace_shoot(dmnsn_line ray, dmnsn_scene *scene, trans.trans = 0.0; dmnsn_line trans_ray = dmnsn_line_construct( - dmnsn_vector_add( - dmnsn_line_point(ray, intersection->t), - dmnsn_vector_mul(epsilon, ray.n) - ), + dmnsn_line_point(ray, intersection->t), ray.n ); - trans_ray.n = ray.n; + trans_ray = dmnsn_line_add_epsilon(trans_ray); dmnsn_color rec = dmnsn_raytrace_shoot(trans_ray, scene, |