//======================================================================== // A simple particle engine with threaded physics // Copyright (c) Marcus Geelnard // Copyright (c) Camilla Löwy // // 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. // // 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: // // 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. // // 2. Altered source versions must be plainly marked as such, and must not // be misrepresented as being the original software. // // 3. This notice may not be removed or altered from any source // distribution. // //======================================================================== #if defined(_MSC_VER) // Make MS math.h define M_PI #define _USE_MATH_DEFINES #endif #include #include #include #include #include #include #include #include #include #define GLFW_INCLUDE_NONE #include // Define tokens for GL_EXT_separate_specular_color if not already defined #ifndef GL_EXT_separate_specular_color #define GL_LIGHT_MODEL_COLOR_CONTROL_EXT 0x81F8 #define GL_SINGLE_COLOR_EXT 0x81F9 #define GL_SEPARATE_SPECULAR_COLOR_EXT 0x81FA #endif // GL_EXT_separate_specular_color //======================================================================== // Type definitions //======================================================================== typedef struct { float x, y, z; } Vec3; // This structure is used for interleaved vertex arrays (see the // draw_particles function) // // NOTE: This structure SHOULD be packed on most systems. It uses 32-bit fields // on 32-bit boundaries, and is a multiple of 64 bits in total (6x32=3x64). If // it does not work, try using pragmas or whatever to force the structure to be // packed. typedef struct { GLfloat s, t; // Texture coordinates GLuint rgba; // Color (four ubytes packed into an uint) GLfloat x, y, z; // Vertex coordinates } Vertex; //======================================================================== // Program control global variables //======================================================================== // Window dimensions float aspect_ratio; // "wireframe" flag (true if we use wireframe view) int wireframe; // Thread synchronization struct { double t; // Time (s) float dt; // Time since last frame (s) int p_frame; // Particle physics frame number int d_frame; // Particle draw frame number cnd_t p_done; // Condition: particle physics done cnd_t d_done; // Condition: particle draw done mtx_t particles_lock; // Particles data sharing mutex } thread_sync; //======================================================================== // Texture declarations (we hard-code them into the source code, since // they are so simple) //======================================================================== #define P_TEX_WIDTH 8 // Particle texture dimensions #define P_TEX_HEIGHT 8 #define F_TEX_WIDTH 16 // Floor texture dimensions #define F_TEX_HEIGHT 16 // Texture object IDs GLuint particle_tex_id, floor_tex_id; // Particle texture (a simple spot) const unsigned char particle_texture[ P_TEX_WIDTH * P_TEX_HEIGHT ] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x22, 0x22, 0x11, 0x00, 0x00, 0x00, 0x11, 0x33, 0x88, 0x77, 0x33, 0x11, 0x00, 0x00, 0x22, 0x88, 0xff, 0xee, 0x77, 0x22, 0x00, 0x00, 0x22, 0x77, 0xee, 0xff, 0x88, 0x22, 0x00, 0x00, 0x11, 0x33, 0x77, 0x88, 0x33, 0x11, 0x00, 0x00, 0x00, 0x11, 0x33, 0x22, 0x11, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // Floor texture (your basic checkered floor) const unsigned char floor_texture[ F_TEX_WIDTH * F_TEX_HEIGHT ] = { 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xff, 0xf0, 0xcc, 0xf0, 0xf0, 0xf0, 0xff, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xf0, 0xcc, 0xee, 0xff, 0xf0, 0xf0, 0xf0, 0xf0, 0x30, 0x66, 0x30, 0x30, 0x30, 0x20, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xee, 0xf0, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xcc, 0xf0, 0xf0, 0xf0, 0x30, 0x30, 0x55, 0x30, 0x30, 0x44, 0x30, 0x30, 0xf0, 0xdd, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0x33, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xff, 0xf0, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x60, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0x33, 0x33, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x33, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x20, 0x30, 0x30, 0xf0, 0xff, 0xf0, 0xf0, 0xdd, 0xf0, 0xf0, 0xff, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x55, 0x33, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xff, 0xf0, 0xf0, 0x30, 0x44, 0x66, 0x30, 0x30, 0x30, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0xaa, 0xf0, 0xf0, 0xcc, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xff, 0xf0, 0xf0, 0xf0, 0xff, 0xf0, 0xdd, 0xf0, 0x30, 0x30, 0x30, 0x77, 0x30, 0x30, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, }; //======================================================================== // These are fixed constants that control the particle engine. In a // modular world, these values should be variables... //======================================================================== // Maximum number of particles #define MAX_PARTICLES 3000 // Life span of a particle (in seconds) #define LIFE_SPAN 8.f // A new particle is born every [BIRTH_INTERVAL] second #define BIRTH_INTERVAL (LIFE_SPAN/(float)MAX_PARTICLES) // Particle size (meters) #define PARTICLE_SIZE 0.7f // Gravitational constant (m/s^2) #define GRAVITY 9.8f // Base initial velocity (m/s) #define VELOCITY 8.f // Bounce friction (1.0 = no friction, 0.0 = maximum friction) #define FRICTION 0.75f // "Fountain" height (m) #define FOUNTAIN_HEIGHT 3.f // Fountain radius (m) #define FOUNTAIN_RADIUS 1.6f // Minimum delta-time for particle phisics (s) #define MIN_DELTA_T (BIRTH_INTERVAL * 0.5f) //======================================================================== // Particle system global variables //======================================================================== // This structure holds all state for a single particle typedef struct { float x,y,z; // Position in space float vx,vy,vz; // Velocity vector float r,g,b; // Color of particle float life; // Life of particle (1.0 = newborn, < 0.0 = dead) int active; // Tells if this particle is active } PARTICLE; // Global vectors holding all particles. We use two vectors for double // buffering. static PARTICLE particles[MAX_PARTICLES]; // Global variable holding the age of the youngest particle static float min_age; // Color of latest born particle (used for fountain lighting) static float glow_color[4]; // Position of latest born particle (used for fountain lighting) static float glow_pos[4]; //======================================================================== // Object material and fog configuration constants //======================================================================== const GLfloat fountain_diffuse[4] = { 0.7f, 1.f, 1.f, 1.f }; const GLfloat fountain_specular[4] = { 1.f, 1.f, 1.f, 1.f }; const GLfloat fountain_shininess = 12.f; const GLfloat floor_diffuse[4] = { 1.f, 0.6f, 0.6f, 1.f }; const GLfloat floor_specular[4] = { 0.6f, 0.6f, 0.6f, 1.f }; const GLfloat floor_shininess = 18.f; const GLfloat fog_color[4] = { 0.1f, 0.1f, 0.1f, 1.f }; //======================================================================== // Print usage information //======================================================================== static void usage(void) { printf("Usage: particles [-bfhs]\n"); printf("Options:\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"); printf(" Esc Exit program\n"); } //======================================================================== // Initialize a new particle //======================================================================== static void init_particle(PARTICLE *p, double t) { float xy_angle, velocity; // Start position of particle is at the fountain blow-out p->x = 0.f; p->y = 0.f; p->z = FOUNTAIN_HEIGHT; // Start velocity is up (Z)... p->vz = 0.7f + (0.3f / 4096.f) * (float) (rand() & 4095); // ...and a randomly chosen X/Y direction xy_angle = (2.f * (float) M_PI / 4096.f) * (float) (rand() & 4095); p->vx = 0.4f * (float) cos(xy_angle); p->vy = 0.4f * (float) sin(xy_angle); // Scale velocity vector according to a time-varying velocity velocity = VELOCITY * (0.8f + 0.1f * (float) (sin(0.5 * t) + sin(1.31 * t))); p->vx *= velocity; p->vy *= velocity; p->vz *= velocity; // Color is time-varying p->r = 0.7f + 0.3f * (float) sin(0.34 * t + 0.1); p->g = 0.6f + 0.4f * (float) sin(0.63 * t + 1.1); p->b = 0.6f + 0.4f * (float) sin(0.91 * t + 2.1); // Store settings for fountain glow lighting glow_pos[0] = 0.4f * (float) sin(1.34 * t); glow_pos[1] = 0.4f * (float) sin(3.11 * t); glow_pos[2] = FOUNTAIN_HEIGHT + 1.f; glow_pos[3] = 1.f; glow_color[0] = p->r; glow_color[1] = p->g; glow_color[2] = p->b; glow_color[3] = 1.f; // The particle is new-born and active p->life = 1.f; p->active = 1; } //======================================================================== // Update a particle //======================================================================== #define FOUNTAIN_R2 (FOUNTAIN_RADIUS+PARTICLE_SIZE/2)*(FOUNTAIN_RADIUS+PARTICLE_SIZE/2) static void update_particle(PARTICLE *p, float dt) { // If the particle is not active, we need not do anything if (!p->active) return; // The particle is getting older... p->life -= dt * (1.f / LIFE_SPAN); // Did the particle die? if (p->life <= 0.f) { p->active = 0; return; } // Apply gravity p->vz = p->vz - GRAVITY * dt; // Update particle position p->x = p->x + p->vx * dt; p->y = p->y + p->vy * dt; p->z = p->z + p->vz * dt; // Simple collision detection + response if (p->vz < 0.f) { // Particles should bounce on the fountain (with friction) if ((p->x * p->x + p->y * p->y) < FOUNTAIN_R2 && p->z < (FOUNTAIN_HEIGHT + PARTICLE_SIZE / 2)) { p->vz = -FRICTION * p->vz; p->z = FOUNTAIN_HEIGHT + PARTICLE_SIZE / 2 + FRICTION * (FOUNTAIN_HEIGHT + PARTICLE_SIZE / 2 - p->z); } // Particles should bounce on the floor (with friction) else if (p->z < PARTICLE_SIZE / 2) { p->vz = -FRICTION * p->vz; p->z = PARTICLE_SIZE / 2 + FRICTION * (PARTICLE_SIZE / 2 - p->z); } } } //======================================================================== // The main frame for the particle engine. Called once per frame. //======================================================================== static void particle_engine(double t, float dt) { int i; float dt2; // Update particles (iterated several times per frame if dt is too large) while (dt > 0.f) { // Calculate delta time for this iteration dt2 = dt < MIN_DELTA_T ? dt : MIN_DELTA_T; for (i = 0; i < MAX_PARTICLES; i++) update_particle(&particles[i], dt2); min_age += dt2; // Should we create any new particle(s)? while (min_age >= BIRTH_INTERVAL) { min_age -= BIRTH_INTERVAL; // Find a dead particle to replace with a new one for (i = 0; i < MAX_PARTICLES; i++) { if (!particles[i].active) { init_particle(&particles[i], t + min_age); update_particle(&particles[i], min_age); break; } } } dt -= dt2; } } //======================================================================== // Draw all active particles. We use OpenGL 1.1 vertex // arrays for this in order to accelerate the drawing. //======================================================================== #define BATCH_PARTICLES 70 // Number of particles to draw in each batch // (70 corresponds to 7.5 KB = will not blow // the L1 data cache on most CPUs) #define PARTICLE_VERTS 4 // Number of vertices per particle static void draw_particles(GLFWwindow* window, double t, float dt) { int i, particle_count; Vertex vertex_array_t[BATCH_PARTICLES * PARTICLE_VERTS]; Vertex* vptr; float alpha; GLuint rgba; Vec3 quad_lower_left, quad_lower_right; GLfloat mat[16]; PARTICLE* pptr; // Here comes the real trick with flat single primitive objects (s.c. // "billboards"): We must rotate the textured primitive so that it // always faces the viewer (is coplanar with the view-plane). // We: // 1) Create the primitive around origo (0,0,0) // 2) Rotate it so that it is coplanar with the view plane // 3) Translate it according to the particle position // Note that 1) and 2) is the same for all particles (done only once). // Get modelview matrix. We will only use the upper left 3x3 part of // the matrix, which represents the rotation. glGetFloatv(GL_MODELVIEW_MATRIX, mat); // 1) & 2) We do it in one swift step: // Although not obvious, the following six lines represent two matrix/ // vector multiplications. The matrix is the inverse 3x3 rotation // matrix (i.e. the transpose of the same matrix), and the two vectors // represent the lower left corner of the quad, PARTICLE_SIZE/2 * // (-1,-1,0), and the lower right corner, PARTICLE_SIZE/2 * (1,-1,0). // The upper left/right corners of the quad is always the negative of // the opposite corners (regardless of rotation). quad_lower_left.x = (-PARTICLE_SIZE / 2) * (mat[0] + mat[1]); quad_lower_left.y = (-PARTICLE_SIZE / 2) * (mat[4] + mat[5]); quad_lower_left.z = (-PARTICLE_SIZE / 2) * (mat[8] + mat[9]); quad_lower_right.x = (PARTICLE_SIZE / 2) * (mat[0] - mat[1]); quad_lower_right.y = (PARTICLE_SIZE / 2) * (mat[4] - mat[5]); quad_lower_right.z = (PARTICLE_SIZE / 2) * (mat[8] - mat[9]); // Don't update z-buffer, since all particles are transparent! glDepthMask(GL_FALSE); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE); // Select particle texture if (!wireframe) { glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, particle_tex_id); } // Set up vertex arrays. We use interleaved arrays, which is easier to // handle (in most situations) and it gives a linear memory access // access pattern (which may give better performance in some // situations). GL_T2F_C4UB_V3F means: 2 floats for texture coords, // 4 ubytes for color and 3 floats for vertex coord (in that order). // Most OpenGL cards / drivers are optimized for this format. glInterleavedArrays(GL_T2F_C4UB_V3F, 0, vertex_array_t); // 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) { struct timespec ts; clock_gettime(CLOCK_REALTIME, &ts); ts.tv_nsec += 100 * 1000 * 1000; ts.tv_sec += ts.tv_nsec / (1000 * 1000 * 1000); ts.tv_nsec %= 1000 * 1000 * 1000; 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_t; pptr = particles; for (i = 0; i < MAX_PARTICLES; i++) { if (pptr->active) { // Calculate particle intensity (we set it to max during 75% // of its life, then it fades out) alpha = 4.f * pptr->life; if (alpha > 1.f) alpha = 1.f; // Convert color from float to 8-bit (store it in a 32-bit // integer using endian independent type casting) ((GLubyte*) &rgba)[0] = (GLubyte)(pptr->r * 255.f); ((GLubyte*) &rgba)[1] = (GLubyte)(pptr->g * 255.f); ((GLubyte*) &rgba)[2] = (GLubyte)(pptr->b * 255.f); ((GLubyte*) &rgba)[3] = (GLubyte)(alpha * 255.f); // 3) Translate the quad to the correct position in modelview // space and store its parameters in vertex arrays (we also // store texture coord and color information for each vertex). // Lower left corner vptr->s = 0.f; vptr->t = 0.f; vptr->rgba = rgba; vptr->x = pptr->x + quad_lower_left.x; vptr->y = pptr->y + quad_lower_left.y; vptr->z = pptr->z + quad_lower_left.z; vptr ++; // Lower right corner vptr->s = 1.f; vptr->t = 0.f; vptr->rgba = rgba; vptr->x = pptr->x + quad_lower_right.x; vptr->y = pptr->y + quad_lower_right.y; vptr->z = pptr->z + quad_lower_right.z; vptr ++; // Upper right corner vptr->s = 1.f; vptr->t = 1.f; vptr->rgba = rgba; vptr->x = pptr->x - quad_lower_left.x; vptr->y = pptr->y - quad_lower_left.y; vptr->z = pptr->z - quad_lower_left.z; vptr ++; // Upper left corner vptr->s = 0.f; vptr->t = 1.f; vptr->rgba = rgba; vptr->x = pptr->x - quad_lower_right.x; vptr->y = pptr->y - quad_lower_right.y; vptr->z = pptr->z - quad_lower_right.z; vptr ++; // Increase count of drawable particles particle_count ++; } // If we have filled up one batch of particles, draw it as a set // of quads using glDrawArrays. if (particle_count >= BATCH_PARTICLES) { // The first argument tells which primitive type we use (QUAD) // The second argument tells the index of the first vertex (0) // The last argument is the vertex count glDrawArrays(GL_QUADS, 0, PARTICLE_VERTS * particle_count); particle_count = 0; vptr = vertex_array_t; } // Next particle pptr++; } // 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); // Disable vertex arrays (Note: glInterleavedArrays implicitly called // glEnableClientState for vertex, texture coord and color arrays) glDisableClientState(GL_VERTEX_ARRAY); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glDisableClientState(GL_COLOR_ARRAY); glDisable(GL_TEXTURE_2D); glDisable(GL_BLEND); glDepthMask(GL_TRUE); } //======================================================================== // Fountain geometry specification //======================================================================== #define FOUNTAIN_SIDE_POINTS 14 #define FOUNTAIN_SWEEP_STEPS 32 static const float fountain_side[FOUNTAIN_SIDE_POINTS * 2] = { 1.2f, 0.f, 1.f, 0.2f, 0.41f, 0.3f, 0.4f, 0.35f, 0.4f, 1.95f, 0.41f, 2.f, 0.8f, 2.2f, 1.2f, 2.4f, 1.5f, 2.7f, 1.55f,2.95f, 1.6f, 3.f, 1.f, 3.f, 0.5f, 3.f, 0.f, 3.f }; static const float fountain_normal[FOUNTAIN_SIDE_POINTS * 2] = { 1.0000f, 0.0000f, 0.6428f, 0.7660f, 0.3420f, 0.9397f, 1.0000f, 0.0000f, 1.0000f, 0.0000f, 0.3420f,-0.9397f, 0.4226f,-0.9063f, 0.5000f,-0.8660f, 0.7660f,-0.6428f, 0.9063f,-0.4226f, 0.0000f,1.00000f, 0.0000f,1.00000f, 0.0000f,1.00000f, 0.0000f,1.00000f }; //======================================================================== // Draw a fountain //======================================================================== static void draw_fountain(void) { static GLuint fountain_list = 0; double angle; float x, y; int m, n; // The first time, we build the fountain display list if (!fountain_list) { fountain_list = glGenLists(1); glNewList(fountain_list, GL_COMPILE_AND_EXECUTE); glMaterialfv(GL_FRONT, GL_DIFFUSE, fountain_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, fountain_specular); glMaterialf(GL_FRONT, GL_SHININESS, fountain_shininess); // Build fountain using triangle strips for (n = 0; n < FOUNTAIN_SIDE_POINTS - 1; n++) { glBegin(GL_TRIANGLE_STRIP); for (m = 0; m <= FOUNTAIN_SWEEP_STEPS; m++) { angle = (double) m * (2.0 * M_PI / (double) FOUNTAIN_SWEEP_STEPS); x = (float) cos(angle); y = (float) sin(angle); // Draw triangle strip glNormal3f(x * fountain_normal[n * 2 + 2], y * fountain_normal[n * 2 + 2], fountain_normal[n * 2 + 3]); glVertex3f(x * fountain_side[n * 2 + 2], y * fountain_side[n * 2 + 2], fountain_side[n * 2 +3 ]); glNormal3f(x * fountain_normal[n * 2], y * fountain_normal[n * 2], fountain_normal[n * 2 + 1]); glVertex3f(x * fountain_side[n * 2], y * fountain_side[n * 2], fountain_side[n * 2 + 1]); } glEnd(); } glEndList(); } else glCallList(fountain_list); } //======================================================================== // Recursive function for building variable tessellated floor //======================================================================== static void tessellate_floor(float x1, float y1, float x2, float y2, int depth) { float delta, x, y; // Last recursion? if (depth >= 5) delta = 999999.f; else { x = (float) (fabs(x1) < fabs(x2) ? fabs(x1) : fabs(x2)); y = (float) (fabs(y1) < fabs(y2) ? fabs(y1) : fabs(y2)); delta = x*x + y*y; } // Recurse further? if (delta < 0.1f) { x = (x1 + x2) * 0.5f; y = (y1 + y2) * 0.5f; tessellate_floor(x1, y1, x, y, depth + 1); tessellate_floor(x, y1, x2, y, depth + 1); tessellate_floor(x1, y, x, y2, depth + 1); tessellate_floor(x, y, x2, y2, depth + 1); } else { glTexCoord2f(x1 * 30.f, y1 * 30.f); glVertex3f( x1 * 80.f, y1 * 80.f, 0.f); glTexCoord2f(x2 * 30.f, y1 * 30.f); glVertex3f( x2 * 80.f, y1 * 80.f, 0.f); glTexCoord2f(x2 * 30.f, y2 * 30.f); glVertex3f( x2 * 80.f, y2 * 80.f, 0.f); glTexCoord2f(x1 * 30.f, y2 * 30.f); glVertex3f( x1 * 80.f, y2 * 80.f, 0.f); } } //======================================================================== // Draw floor. We build the floor recursively and let the tessellation in the // center (near x,y=0,0) be high, while the tessellation around the edges be // low. //======================================================================== static void draw_floor(void) { static GLuint floor_list = 0; if (!wireframe) { glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, floor_tex_id); } // The first time, we build the floor display list if (!floor_list) { floor_list = glGenLists(1); glNewList(floor_list, GL_COMPILE_AND_EXECUTE); glMaterialfv(GL_FRONT, GL_DIFFUSE, floor_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, floor_specular); glMaterialf(GL_FRONT, GL_SHININESS, floor_shininess); // Draw floor as a bunch of triangle strips (high tessellation // improves lighting) glNormal3f(0.f, 0.f, 1.f); glBegin(GL_QUADS); tessellate_floor(-1.f, -1.f, 0.f, 0.f, 0); tessellate_floor( 0.f, -1.f, 1.f, 0.f, 0); tessellate_floor( 0.f, 0.f, 1.f, 1.f, 0); tessellate_floor(-1.f, 0.f, 0.f, 1.f, 0); glEnd(); glEndList(); } else glCallList(floor_list); glDisable(GL_TEXTURE_2D); } //======================================================================== // Position and configure light sources //======================================================================== static void setup_lights(void) { float l1pos[4], l1amb[4], l1dif[4], l1spec[4]; float l2pos[4], l2amb[4], l2dif[4], l2spec[4]; // Set light source 1 parameters l1pos[0] = 0.f; l1pos[1] = -9.f; l1pos[2] = 8.f; l1pos[3] = 1.f; l1amb[0] = 0.2f; l1amb[1] = 0.2f; l1amb[2] = 0.2f; l1amb[3] = 1.f; l1dif[0] = 0.8f; l1dif[1] = 0.4f; l1dif[2] = 0.2f; l1dif[3] = 1.f; l1spec[0] = 1.f; l1spec[1] = 0.6f; l1spec[2] = 0.2f; l1spec[3] = 0.f; // Set light source 2 parameters l2pos[0] = -15.f; l2pos[1] = 12.f; l2pos[2] = 1.5f; l2pos[3] = 1.f; l2amb[0] = 0.f; l2amb[1] = 0.f; l2amb[2] = 0.f; l2amb[3] = 1.f; l2dif[0] = 0.2f; l2dif[1] = 0.4f; l2dif[2] = 0.8f; l2dif[3] = 1.f; l2spec[0] = 0.2f; l2spec[1] = 0.6f; l2spec[2] = 1.f; l2spec[3] = 0.f; glLightfv(GL_LIGHT1, GL_POSITION, l1pos); glLightfv(GL_LIGHT1, GL_AMBIENT, l1amb); glLightfv(GL_LIGHT1, GL_DIFFUSE, l1dif); glLightfv(GL_LIGHT1, GL_SPECULAR, l1spec); glLightfv(GL_LIGHT2, GL_POSITION, l2pos); glLightfv(GL_LIGHT2, GL_AMBIENT, l2amb); glLightfv(GL_LIGHT2, GL_DIFFUSE, l2dif); glLightfv(GL_LIGHT2, GL_SPECULAR, l2spec); glLightfv(GL_LIGHT3, GL_POSITION, glow_pos); glLightfv(GL_LIGHT3, GL_DIFFUSE, glow_color); glLightfv(GL_LIGHT3, GL_SPECULAR, glow_color); glEnable(GL_LIGHT1); glEnable(GL_LIGHT2); glEnable(GL_LIGHT3); } //======================================================================== // Main rendering function //======================================================================== static void draw_scene(GLFWwindow* window, double t) { double xpos, ypos, zpos, angle_x, angle_y, angle_z; static double t_old = 0.0; float dt; mat4x4 projection; // Calculate frame-to-frame delta time dt = (float) (t - t_old); t_old = t; mat4x4_perspective(projection, 65.f * (float) M_PI / 180.f, aspect_ratio, 1.0, 60.0); glClearColor(0.1f, 0.1f, 0.1f, 1.f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadMatrixf((const GLfloat*) projection); // Setup camera glMatrixMode(GL_MODELVIEW); glLoadIdentity(); // Rotate camera angle_x = 90.0 - 10.0; angle_y = 10.0 * sin(0.3 * t); angle_z = 10.0 * t; glRotated(-angle_x, 1.0, 0.0, 0.0); glRotated(-angle_y, 0.0, 1.0, 0.0); glRotated(-angle_z, 0.0, 0.0, 1.0); // Translate camera xpos = 15.0 * sin((M_PI / 180.0) * angle_z) + 2.0 * sin((M_PI / 180.0) * 3.1 * t); ypos = -15.0 * cos((M_PI / 180.0) * angle_z) + 2.0 * cos((M_PI / 180.0) * 2.9 * t); zpos = 4.0 + 2.0 * cos((M_PI / 180.0) * 4.9 * t); glTranslated(-xpos, -ypos, -zpos); glFrontFace(GL_CCW); glCullFace(GL_BACK); glEnable(GL_CULL_FACE); setup_lights(); glEnable(GL_LIGHTING); glEnable(GL_FOG); glFogi(GL_FOG_MODE, GL_EXP); glFogf(GL_FOG_DENSITY, 0.05f); glFogfv(GL_FOG_COLOR, fog_color); draw_floor(); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glDepthMask(GL_TRUE); draw_fountain(); glDisable(GL_LIGHTING); glDisable(GL_FOG); // Particles must be drawn after all solid objects have been drawn draw_particles(window, t, dt); // Z-buffer not needed anymore glDisable(GL_DEPTH_TEST); } //======================================================================== // Window resize callback function //======================================================================== static void resize_callback(GLFWwindow* window, int width, int height) { glViewport(0, 0, width, height); aspect_ratio = height ? width / (float) height : 1.f; } //======================================================================== // Key callback functions //======================================================================== static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) { if (action == GLFW_PRESS) { switch (key) { case GLFW_KEY_ESCAPE: glfwSetWindowShouldClose(window, GLFW_TRUE); break; case GLFW_KEY_W: wireframe = !wireframe; glPolygonMode(GL_FRONT_AND_BACK, wireframe ? GL_LINE : GL_FILL); break; default: break; } } } //======================================================================== // Thread for updating particle physics //======================================================================== 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 (!glfwWindowShouldClose(window) && thread_sync.p_frame > thread_sync.d_frame) { struct timespec ts; clock_gettime(CLOCK_REALTIME, &ts); ts.tv_nsec += 100 * 1000 * 1000; ts.tv_sec += ts.tv_nsec / (1000 * 1000 * 1000); ts.tv_nsec %= 1000 * 1000 * 1000; cnd_timedwait(&thread_sync.d_done, &thread_sync.particles_lock, &ts); } if (glfwWindowShouldClose(window)) break; // Update particles particle_engine(thread_sync.t, thread_sync.dt); // Update frame counter thread_sync.p_frame++; // Unlock mutex and signal drawing thread mtx_unlock(&thread_sync.particles_lock); cnd_signal(&thread_sync.p_done); } return 0; } //======================================================================== // main //======================================================================== int main(int argc, char** argv) { int ch, width, height; thrd_t physics_thread = 0; GLFWwindow* window; GLFWmonitor* monitor = NULL; if (!glfwInit()) { fprintf(stderr, "Failed to initialize GLFW\n"); exit(EXIT_FAILURE); } while ((ch = getopt(argc, argv, "fh")) != -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 create GLFW window\n"); glfwTerminate(); exit(EXIT_FAILURE); } if (monitor) glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED); glfwMakeContextCurrent(window); gladLoadGL(glfwGetProcAddress); glfwSwapInterval(1); glfwSetFramebufferSizeCallback(window, resize_callback); glfwSetKeyCallback(window, key_callback); // Set initial aspect ratio glfwGetFramebufferSize(window, &width, &height); resize_callback(window, width, height); // Upload particle texture glGenTextures(1, &particle_tex_id); glBindTexture(GL_TEXTURE_2D, particle_tex_id); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, P_TEX_WIDTH, P_TEX_HEIGHT, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, particle_texture); // Upload floor texture glGenTextures(1, &floor_tex_id); glBindTexture(GL_TEXTURE_2D, floor_tex_id); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, F_TEX_WIDTH, F_TEX_HEIGHT, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, floor_texture); if (glfwExtensionSupported("GL_EXT_separate_specular_color")) { glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL_EXT, GL_SEPARATE_SPECULAR_COLOR_EXT); } // Set filled polygon mode as default (not wireframe) glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); wireframe = 0; // Set initial times thread_sync.t = 0.0; thread_sync.dt = 0.001f; 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, window) != thrd_success) { glfwTerminate(); exit(EXIT_FAILURE); } glfwSetTime(0.0); while (!glfwWindowShouldClose(window)) { draw_scene(window, glfwGetTime()); glfwSwapBuffers(window); glfwPollEvents(); } thrd_join(physics_thread, NULL); glfwDestroyWindow(window); glfwTerminate(); exit(EXIT_SUCCESS); }