From 89627e4cd06e06c2044b2041c1efdb8dca78b5c6 Mon Sep 17 00:00:00 2001 From: Camilla Berglund Date: Sat, 11 Jan 2014 20:46:24 +0100 Subject: [PATCH] Cleaned up particles example. --- .gitignore | 1 + examples/particles.c | 260 +++++++++++++++++-------------------------- 2 files changed, 106 insertions(+), 155 deletions(-) diff --git a/.gitignore b/.gitignore index 4ec9d0b3..4f8ddbc9 100644 --- a/.gitignore +++ b/.gitignore @@ -44,6 +44,7 @@ examples/*.exe examples/boing examples/gears examples/heightmap +examples/particles examples/splitview examples/simple examples/wave diff --git a/examples/particles.c b/examples/particles.c index 4230fe71..7a4725f8 100644 --- a/examples/particles.c +++ b/examples/particles.c @@ -1,40 +1,27 @@ //======================================================================== -// This is a simple, but cool particle engine (buzz-word meaning many -// small objects that are treated as points and drawn as textures -// projected on simple geometry). +// A simple particle engine with threaded physics +// Copyright (c) Marcus Geelnard +// Copyright (c) Camilla Berglund // -// This demonstration generates a colorful fountain-like animation. It -// uses several advanced OpenGL teqhniques: +// This software is provided 'as-is', without any express or implied +// warranty. In no event will the authors be held liable for any damages +// arising from the use of this software. // -// 1) Lighting (per vertex) -// 2) Alpha blending -// 3) Fog -// 4) Texturing -// 5) Display lists (for drawing the static environment geometry) -// 6) Vertex arrays (for drawing the particles) -// 7) GL_EXT_separate_specular_color is used (if available) +// Permission is granted to anyone to use this software for any purpose, +// including commercial applications, and to alter it and redistribute it +// freely, subject to the following restrictions: // -// Even more so, this program uses multi threading. The program is -// essentialy divided into a main rendering thread and a particle physics -// calculation thread. My benchmarks under Windows 2000 on a single -// processor system show that running this program as two threads instead -// of a single thread means no difference (there may be a very marginal -// advantage for the multi threaded case). On dual processor systems I -// have had reports of 5-25% of speed increase when running this program -// as two threads instead of one thread. +// 1. The origin of this software must not be misrepresented; you must not +// claim that you wrote the original software. If you use this software +// in a product, an acknowledgment in the product documentation would +// be appreciated but is not required. // -// The default behaviour of this program is to use two threads. To force -// a single thread to be used, use the command line switch -s. +// 2. Altered source versions must be plainly marked as such, and must not +// be misrepresented as being the original software. // -// To run a fixed length benchmark (60 s), use the command line switch -b. +// 3. This notice may not be removed or altered from any source +// distribution. // -// Benchmark results (640x480x16, best of three tests): -// -// CPU GFX 1 thread 2 threads -// Athlon XP 2700+ GeForce Ti4200 (oc) 757 FPS 759 FPS -// P4 2.8 GHz (SMT) GeForce FX5600 548 FPS 550 FPS -// -// One more thing: Press 'w' during the demo to toggle wireframe mode. //======================================================================== #include @@ -60,10 +47,6 @@ #define M_PI 3.141592654 #endif -// Desired fullscreen resolution -#define WIDTH 640 -#define HEIGHT 480 - //======================================================================== // Type definitions @@ -93,18 +76,12 @@ typedef struct // Program control global variables //======================================================================== -// "Running" flag (true if program shall continue to run) -int running; - // Window dimensions -int width, height; +float aspect_ratio; // "wireframe" flag (true if we use wireframe view) int wireframe; -// "multithreading" flag (true if we use multithreading) -int multithreading; - // Thread synchronization struct { double t; // Time (s) @@ -245,11 +222,11 @@ const GLfloat fog_color[4] = { 0.1f, 0.1f, 0.1f, 1.f }; static void usage(void) { - printf("Usage: particles [-hbs]\n"); + printf("Usage: particles [-bfhs]\n"); printf("Options:\n"); - printf(" -b Benchmark (run program for 60 seconds)\n"); - printf(" -s Run program as single thread (default is to use two threads)\n"); + printf(" -f Run in full screen\n"); printf(" -h Display this help\n"); + printf(" -s Run program as single thread (default is to use two threads)\n"); printf("\n"); printf("Program runtime controls:\n"); printf(" W Toggle wireframe mode\n"); @@ -411,7 +388,7 @@ static void particle_engine(double t, float dt) // the L1 data cache on most CPUs) #define PARTICLE_VERTS 4 // Number of vertices per particle -static void draw_particles(double t, float dt) +static void draw_particles(GLFWwindow* window, double t, float dt) { int i, particle_count; Vertex vertex_array[BATCH_PARTICLES * PARTICLE_VERTS]; @@ -471,30 +448,22 @@ static void draw_particles(double t, float dt) // Most OpenGL cards / drivers are optimized for this format. glInterleavedArrays(GL_T2F_C4UB_V3F, 0, vertex_array); - // Is particle physics carried out in a separate thread? - if (multithreading) + // Wait for particle physics thread to be done + mtx_lock(&thread_sync.particles_lock); + while (!glfwWindowShouldClose(window) && + thread_sync.p_frame <= thread_sync.d_frame) { - // Wait for particle physics thread to be done - mtx_lock(&thread_sync.particles_lock); - while (running && thread_sync.p_frame <= thread_sync.d_frame) - { - struct timespec ts = { 0, 100000000 }; - cnd_timedwait(&thread_sync.p_done, &thread_sync.particles_lock, &ts); - } - - // Store the frame time and delta time for the physics thread - thread_sync.t = t; - thread_sync.dt = dt; - - // Update frame counter - thread_sync.d_frame++; - } - else - { - // Perform particle physics in this thread - particle_engine(t, dt); + struct timespec ts = { 0, 100000000 }; + cnd_timedwait(&thread_sync.p_done, &thread_sync.particles_lock, &ts); } + // Store the frame time and delta time for the physics thread + thread_sync.t = t; + thread_sync.dt = dt; + + // Update frame counter + thread_sync.d_frame++; + // Loop through all particles and build vertex arrays. particle_count = 0; vptr = vertex_array; @@ -577,13 +546,9 @@ static void draw_particles(double t, float dt) pptr++; } - // We are done with the particle data: Unlock mutex and signal physics - // thread - if (multithreading) - { - mtx_unlock(&thread_sync.particles_lock); - cnd_signal(&thread_sync.d_done); - } + // We are done with the particle data + mtx_unlock(&thread_sync.particles_lock); + cnd_signal(&thread_sync.d_done); // Draw final batch of particles (if any) glDrawArrays(GL_QUADS, 0, PARTICLE_VERTS * particle_count); @@ -812,7 +777,7 @@ static void setup_lights(void) // Main rendering function //======================================================================== -static void draw_scene(double t) +static void draw_scene(GLFWwindow* window, double t) { double xpos, ypos, zpos, angle_x, angle_y, angle_z; static double t_old = 0.0; @@ -822,14 +787,12 @@ static void draw_scene(double t) dt = (float) (t - t_old); t_old = t; - glViewport(0, 0, width, height); - glClearColor(0.1f, 0.1f, 0.1f, 1.f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); - gluPerspective(65.0, (double) width / (double) height, 1.0, 60.0); + gluPerspective(65.0, aspect_ratio, 1.0, 60.0); // Setup camera glMatrixMode(GL_MODELVIEW); @@ -875,7 +838,7 @@ static void draw_scene(double t) glDisable(GL_FOG); // Particles must be drawn after all solid objects have been drawn - draw_particles(t, dt); + draw_particles(window, t, dt); // Z-buffer not needed anymore glDisable(GL_DEPTH_TEST); @@ -886,10 +849,10 @@ static void draw_scene(double t) // Window resize callback function //======================================================================== -static void resize_callback(GLFWwindow* window, int w, int h) +static void resize_callback(GLFWwindow* window, int width, int height) { - width = w; - height = h > 0 ? h : 1; // Prevent division by zero in aspect calc. + glViewport(0, 0, width, height); + aspect_ratio = height ? width / (float) height : 1.f; } @@ -904,7 +867,7 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action, switch (key) { case GLFW_KEY_ESCAPE: - running = 0; + glfwSetWindowShouldClose(window, GL_TRUE); break; case GLFW_KEY_W: wireframe = !wireframe; @@ -924,18 +887,21 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action, static int physics_thread_main(void* arg) { + GLFWwindow* window = arg; + for (;;) { mtx_lock(&thread_sync.particles_lock); // Wait for particle drawing to be done - while (running && thread_sync.p_frame > thread_sync.d_frame) + while (!glfwWindowShouldClose(window) && + thread_sync.p_frame > thread_sync.d_frame) { struct timespec ts = { 0, 100000000 }; cnd_timedwait(&thread_sync.d_done, &thread_sync.particles_lock, &ts); } - if (!running) + if (glfwWindowShouldClose(window)) break; // Update particles @@ -959,30 +925,10 @@ static int physics_thread_main(void* arg) int main(int argc, char** argv) { - int i, ch, frames, benchmark; - double t0, t; + int ch, width, height; thrd_t physics_thread = 0; GLFWwindow* window; - - // Use multithreading by default, but don't benchmark - multithreading = 1; - benchmark = 0; - - while ((ch = getopt(argc, argv, "bhs")) != -1) - { - switch (ch) - { - case 'b': - benchmark = 1; - break; - case 'h': - usage(); - exit(EXIT_SUCCESS); - case 's': - multithreading = 0; - break; - } - } + GLFWmonitor* monitor = NULL; if (!glfwInit()) { @@ -990,23 +936,58 @@ int main(int argc, char** argv) exit(EXIT_FAILURE); } - window = glfwCreateWindow(WIDTH, HEIGHT, "Particle Engine", - glfwGetPrimaryMonitor(), NULL); + while ((ch = getopt(argc, argv, "fhs")) != -1) + { + switch (ch) + { + case 'f': + monitor = glfwGetPrimaryMonitor(); + break; + case 'h': + usage(); + exit(EXIT_SUCCESS); + } + } + + if (monitor) + { + const GLFWvidmode* mode = glfwGetVideoMode(monitor); + + glfwWindowHint(GLFW_RED_BITS, mode->redBits); + glfwWindowHint(GLFW_GREEN_BITS, mode->greenBits); + glfwWindowHint(GLFW_BLUE_BITS, mode->blueBits); + glfwWindowHint(GLFW_REFRESH_RATE, mode->refreshRate); + + width = mode->width; + height = mode->height; + } + else + { + width = 640; + height = 480; + } + + window = glfwCreateWindow(width, height, "Particle Engine", monitor, NULL); if (!window) { - fprintf(stderr, "Failed to open GLFW window\n"); + fprintf(stderr, "Failed to create GLFW window\n"); glfwTerminate(); exit(EXIT_FAILURE); } - glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED); + if (monitor) + glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED); glfwMakeContextCurrent(window); - glfwSwapInterval(0); + glfwSwapInterval(1); glfwSetWindowSizeCallback(window, resize_callback); glfwSetKeyCallback(window, key_callback); + // Set initial aspect ratio + glfwGetWindowSize(window, &width, &height); + resize_callback(window, width, height); + // Upload particle texture glGenTextures(1, &particle_tex_id); glBindTexture(GL_TEXTURE_2D, particle_tex_id); @@ -1039,64 +1020,33 @@ int main(int argc, char** argv) glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); wireframe = 0; - // Clear particle system - for (i = 0; i < MAX_PARTICLES; i++) - particles[i].active = 0; - - min_age = 0.f; - - running = 1; - // Set initial times thread_sync.t = 0.0; thread_sync.dt = 0.001f; + thread_sync.p_frame = 0; + thread_sync.d_frame = 0; - if (multithreading) + mtx_init(&thread_sync.particles_lock, mtx_timed); + cnd_init(&thread_sync.p_done); + cnd_init(&thread_sync.d_done); + + if (thrd_create(&physics_thread, physics_thread_main, window) != thrd_success) { - thread_sync.p_frame = 0; - thread_sync.d_frame = 0; - mtx_init(&thread_sync.particles_lock, mtx_timed); - cnd_init(&thread_sync.p_done); - cnd_init(&thread_sync.d_done); - - if (thrd_create(&physics_thread, physics_thread_main, NULL) != thrd_success) - { - glfwTerminate(); - exit(EXIT_FAILURE); - } + glfwTerminate(); + exit(EXIT_FAILURE); } - t0 = glfwGetTime(); - frames = 0; + glfwSetTime(0.0); - while (running) + while (!glfwWindowShouldClose(window)) { - // Get frame time - t = glfwGetTime() - t0; - - draw_scene(t); + draw_scene(window, glfwGetTime()); glfwSwapBuffers(window); glfwPollEvents(); - - running = running && !glfwWindowShouldClose(window); - - frames++; - - // End of benchmark? - if (benchmark && t >= 60.0) - running = 0; } - t = glfwGetTime() - t0; - - // Wait for particle physics thread to die - if (multithreading) - thrd_join(physics_thread, NULL); - - // Display profiling information - printf("%d frames in %.2f seconds = %.1f FPS", frames, t, (double) frames / t); - printf(" (multithreading %s)\n", multithreading ? "on" : "off"); + thrd_join(physics_thread, NULL); glfwDestroyWindow(window); glfwTerminate();