:wMerge branch 'gl-window' into main

1 files changed, 1073 insertions, 0 deletions

diff --git a/libs/glfw-3.3.8/examples/particles.c b/libs/glfw-3.3.8/examples/particles.c
new file mode 100644
index 0000000..9556cca
--- /dev/null
+++ b/libs/glfw-3.3.8/examples/particles.c
@@ -0,0 +1,1073 @@
+//========================================================================
+// A simple particle engine with threaded physics
+// Copyright (c) Marcus Geelnard
+// Copyright (c) Camilla Löwy <elmindreda@glfw.org>
+//
+// 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 <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+#include <time.h>
+
+#include <tinycthread.h>
+#include <getopt.h>
+#include <linmath.h>
+
+#include <glad/gl.h>
+#define GLFW_INCLUDE_NONE
+#include <GLFW/glfw3.h>
+
+// 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[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);
+
+    // 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;
+    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;
+        }
+
+        // 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);
+}
+