From 3ce0bfcd0e16d909b7495f07c9e8a82e4781ee88 Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Sun, 14 Jun 2009 01:48:35 +0000 Subject: Make raytracing engine multi-threaded. --- libdimension/raytrace.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 libdimension/raytrace.c (limited to 'libdimension/raytrace.c') diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c new file mode 100644 index 0000000..5d728d5 --- /dev/null +++ b/libdimension/raytrace.c @@ -0,0 +1,103 @@ +/************************************************************************* + * Copyright (C) 2008 Tavian Barnes * + * * + * 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 * + * . * + *************************************************************************/ + +#include "dimension.h" +#include /* 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); + } + } + } + } +} -- cgit v1.2.3