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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);
}
}
}
}
return NULL;
}
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