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-rw-r--r--libdimension/raytrace.c103
1 files changed, 103 insertions, 0 deletions
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
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+++ b/libdimension/raytrace.c
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+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
+ * *
+ * This file is part of The Dimension Library. *
+ * *
+ * The Dimension Library is free software; you can redistribute it and/ *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version. *
+ * *
+ * The Dimension Library is distributed in the hope that it will be *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
+ * Lesser General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU Lesser General Public *
+ * License along with this program. If not, see *
+ * <http://www.gnu.org/licenses/>. *
+ *************************************************************************/
+
+#include "dimension.h"
+#include <unistd.h> /* For sysconf */
+
+typedef struct {
+ dmnsn_scene *scene;
+ unsigned int i, n;
+} dmnsn_raytrace_thread_payload;
+
+static void *dmnsn_raytrace_scene_thread(void *arg);
+
+void
+dmnsn_raytrace_scene(dmnsn_scene *scene)
+{
+ long n = sysconf(_SC_NPROCESSORS_ONLN);
+ unsigned int i;
+ pthread_t thread;
+ dmnsn_raytrace_thread_payload payload;
+ dmnsn_array *threads, *payloads;
+
+ threads = dmnsn_new_array(sizeof(pthread_t));
+ payloads = dmnsn_new_array(sizeof(dmnsn_raytrace_thread_payload));
+
+ if (n <= 0) n = 1;
+
+ payload.scene = scene;
+ payload.n = n;
+ for (i = 0; i < n; ++i) {
+ payload.i = i;
+ dmnsn_array_push(payloads, &payload);
+
+ pthread_create(&thread, NULL, &dmnsn_raytrace_scene_thread,
+ dmnsn_array_at(payloads, i));
+ dmnsn_array_push(threads, &thread);
+ }
+
+ for (i = 0; i < n; ++i) {
+ dmnsn_array_get(threads, i, &thread);
+ pthread_join(thread, NULL);
+ }
+
+ dmnsn_delete_array(payloads);
+ dmnsn_delete_array(threads);
+}
+
+/* Raytrace a scene */
+static void *
+dmnsn_raytrace_scene_thread(void *arg)
+{
+ unsigned int i, j, k;
+ dmnsn_object *object;
+ dmnsn_line ray;
+ dmnsn_raytrace_thread_payload *payload = (dmnsn_raytrace_thread_payload *)arg;
+ dmnsn_scene *scene = payload->scene;
+ dmnsn_array *intersections;
+
+ /* Iterate through each pixel */
+ for (i = 0; i < scene->canvas->x; ++i) {
+ for (j = 0; j < scene->canvas->y; ++j) {
+ /* Only do the pixels assigned to this thread */
+ if ((j*scene->canvas->x + i)%payload->n == payload->i) {
+ /* Set the pixel to the background color */
+ dmnsn_set_pixel(scene->canvas, i, j, scene->background);
+
+ /* Get the ray corresponding to the (i,j)th pixel */
+ ray = (*scene->camera->ray_fn)(scene->camera, scene->canvas, i, j);
+
+ for (k = 0; k < scene->objects->length; ++k) {
+ dmnsn_array_get(scene->objects, k, &object);
+ /* Test for an intersection with an object */
+ intersections = (*object->intersections_fn)(object, ray);
+ if (intersections->length > 0) {
+ /* Mark intersections white */
+ dmnsn_set_pixel(scene->canvas, i, j,
+ dmnsn_color_from_XYZ(dmnsn_whitepoint));
+ dmnsn_delete_array(intersections);
+ break;
+ }
+ dmnsn_delete_array(intersections);
+ }
+ }
+ }
+ }
+}