add glfw library

1 files changed, 462 insertions, 0 deletions

diff --git a/libs/glfw-3.3.8/examples/wave.c b/libs/glfw-3.3.8/examples/wave.c
new file mode 100644
index 0000000..7acb8b9
--- /dev/null
+++ b/libs/glfw-3.3.8/examples/wave.c
@@ -0,0 +1,462 @@
+/*****************************************************************************
+ * Wave Simulation in OpenGL
+ * (C) 2002 Jakob Thomsen
+ * http://home.in.tum.de/~thomsen
+ * Modified for GLFW by Sylvain Hellegouarch - sh@programmationworld.com
+ * Modified for variable frame rate by Marcus Geelnard
+ * 2003-Jan-31: Minor cleanups and speedups / MG
+ * 2010-10-24: Formatting and cleanup - Camilla Löwy
+ *****************************************************************************/
+
+#if defined(_MSC_VER)
+ // Make MS math.h define M_PI
+ #define _USE_MATH_DEFINES
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include <glad/gl.h>
+#define GLFW_INCLUDE_NONE
+#include <GLFW/glfw3.h>
+
+#include <linmath.h>
+
+// Maximum delta T to allow for differential calculations
+#define MAX_DELTA_T 0.01
+
+// Animation speed (10.0 looks good)
+#define ANIMATION_SPEED 10.0
+
+GLfloat alpha = 210.f, beta = -70.f;
+GLfloat zoom = 2.f;
+
+double cursorX;
+double cursorY;
+
+struct Vertex
+{
+    GLfloat x, y, z;
+    GLfloat r, g, b;
+};
+
+#define GRIDW 50
+#define GRIDH 50
+#define VERTEXNUM (GRIDW*GRIDH)
+
+#define QUADW (GRIDW - 1)
+#define QUADH (GRIDH - 1)
+#define QUADNUM (QUADW*QUADH)
+
+GLuint quad[4 * QUADNUM];
+struct Vertex vertex[VERTEXNUM];
+
+/* The grid will look like this:
+ *
+ *      3   4   5
+ *      *---*---*
+ *      |   |   |
+ *      | 0 | 1 |
+ *      |   |   |
+ *      *---*---*
+ *      0   1   2
+ */
+
+//========================================================================
+// Initialize grid geometry
+//========================================================================
+
+void init_vertices(void)
+{
+    int x, y, p;
+
+    // Place the vertices in a grid
+    for (y = 0;  y < GRIDH;  y++)
+    {
+        for (x = 0;  x < GRIDW;  x++)
+        {
+            p = y * GRIDW + x;
+
+            vertex[p].x = (GLfloat) (x - GRIDW / 2) / (GLfloat) (GRIDW / 2);
+            vertex[p].y = (GLfloat) (y - GRIDH / 2) / (GLfloat) (GRIDH / 2);
+            vertex[p].z = 0;
+
+            if ((x % 4 < 2) ^ (y % 4 < 2))
+                vertex[p].r = 0.0;
+            else
+                vertex[p].r = 1.0;
+
+            vertex[p].g = (GLfloat) y / (GLfloat) GRIDH;
+            vertex[p].b = 1.f - ((GLfloat) x / (GLfloat) GRIDW + (GLfloat) y / (GLfloat) GRIDH) / 2.f;
+        }
+    }
+
+    for (y = 0;  y < QUADH;  y++)
+    {
+        for (x = 0;  x < QUADW;  x++)
+        {
+            p = 4 * (y * QUADW + x);
+
+            quad[p + 0] = y       * GRIDW + x;     // Some point
+            quad[p + 1] = y       * GRIDW + x + 1; // Neighbor at the right side
+            quad[p + 2] = (y + 1) * GRIDW + x + 1; // Upper right neighbor
+            quad[p + 3] = (y + 1) * GRIDW + x;     // Upper neighbor
+        }
+    }
+}
+
+double dt;
+double p[GRIDW][GRIDH];
+double vx[GRIDW][GRIDH], vy[GRIDW][GRIDH];
+double ax[GRIDW][GRIDH], ay[GRIDW][GRIDH];
+
+//========================================================================
+// Initialize grid
+//========================================================================
+
+void init_grid(void)
+{
+    int x, y;
+    double dx, dy, d;
+
+    for (y = 0; y < GRIDH;  y++)
+    {
+        for (x = 0; x < GRIDW;  x++)
+        {
+            dx = (double) (x - GRIDW / 2);
+            dy = (double) (y - GRIDH / 2);
+            d = sqrt(dx * dx + dy * dy);
+            if (d < 0.1 * (double) (GRIDW / 2))
+            {
+                d = d * 10.0;
+                p[x][y] = -cos(d * (M_PI / (double)(GRIDW * 4))) * 100.0;
+            }
+            else
+                p[x][y] = 0.0;
+
+            vx[x][y] = 0.0;
+            vy[x][y] = 0.0;
+        }
+    }
+}
+
+
+//========================================================================
+// Draw scene
+//========================================================================
+
+void draw_scene(GLFWwindow* window)
+{
+    // Clear the color and depth buffers
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    // We don't want to modify the projection matrix
+    glMatrixMode(GL_MODELVIEW);
+    glLoadIdentity();
+
+    // Move back
+    glTranslatef(0.0, 0.0, -zoom);
+    // Rotate the view
+    glRotatef(beta, 1.0, 0.0, 0.0);
+    glRotatef(alpha, 0.0, 0.0, 1.0);
+
+    glDrawElements(GL_QUADS, 4 * QUADNUM, GL_UNSIGNED_INT, quad);
+
+    glfwSwapBuffers(window);
+}
+
+
+//========================================================================
+// Initialize Miscellaneous OpenGL state
+//========================================================================
+
+void init_opengl(void)
+{
+    // Use Gouraud (smooth) shading
+    glShadeModel(GL_SMOOTH);
+
+    // Switch on the z-buffer
+    glEnable(GL_DEPTH_TEST);
+
+    glEnableClientState(GL_VERTEX_ARRAY);
+    glEnableClientState(GL_COLOR_ARRAY);
+    glVertexPointer(3, GL_FLOAT, sizeof(struct Vertex), vertex);
+    glColorPointer(3, GL_FLOAT, sizeof(struct Vertex), &vertex[0].r); // Pointer to the first color
+
+    glPointSize(2.0);
+
+    // Background color is black
+    glClearColor(0, 0, 0, 0);
+}
+
+
+//========================================================================
+// Modify the height of each vertex according to the pressure
+//========================================================================
+
+void adjust_grid(void)
+{
+    int pos;
+    int x, y;
+
+    for (y = 0; y < GRIDH;  y++)
+    {
+        for (x = 0;  x < GRIDW;  x++)
+        {
+            pos = y * GRIDW + x;
+            vertex[pos].z = (float) (p[x][y] * (1.0 / 50.0));
+        }
+    }
+}
+
+
+//========================================================================
+// Calculate wave propagation
+//========================================================================
+
+void calc_grid(void)
+{
+    int x, y, x2, y2;
+    double time_step = dt * ANIMATION_SPEED;
+
+    // Compute accelerations
+    for (x = 0;  x < GRIDW;  x++)
+    {
+        x2 = (x + 1) % GRIDW;
+        for(y = 0; y < GRIDH; y++)
+            ax[x][y] = p[x][y] - p[x2][y];
+    }
+
+    for (y = 0;  y < GRIDH;  y++)
+    {
+        y2 = (y + 1) % GRIDH;
+        for(x = 0; x < GRIDW; x++)
+            ay[x][y] = p[x][y] - p[x][y2];
+    }
+
+    // Compute speeds
+    for (x = 0;  x < GRIDW;  x++)
+    {
+        for (y = 0;  y < GRIDH;  y++)
+        {
+            vx[x][y] = vx[x][y] + ax[x][y] * time_step;
+            vy[x][y] = vy[x][y] + ay[x][y] * time_step;
+        }
+    }
+
+    // Compute pressure
+    for (x = 1;  x < GRIDW;  x++)
+    {
+        x2 = x - 1;
+        for (y = 1;  y < GRIDH;  y++)
+        {
+            y2 = y - 1;
+            p[x][y] = p[x][y] + (vx[x2][y] - vx[x][y] + vy[x][y2] - vy[x][y]) * time_step;
+        }
+    }
+}
+
+
+//========================================================================
+// Print errors
+//========================================================================
+
+static void error_callback(int error, const char* description)
+{
+    fprintf(stderr, "Error: %s\n", description);
+}
+
+
+//========================================================================
+// Handle key strokes
+//========================================================================
+
+void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
+{
+    if (action != GLFW_PRESS)
+        return;
+
+    switch (key)
+    {
+        case GLFW_KEY_ESCAPE:
+            glfwSetWindowShouldClose(window, GLFW_TRUE);
+            break;
+        case GLFW_KEY_SPACE:
+            init_grid();
+            break;
+        case GLFW_KEY_LEFT:
+            alpha += 5;
+            break;
+        case GLFW_KEY_RIGHT:
+            alpha -= 5;
+            break;
+        case GLFW_KEY_UP:
+            beta -= 5;
+            break;
+        case GLFW_KEY_DOWN:
+            beta += 5;
+            break;
+        case GLFW_KEY_PAGE_UP:
+            zoom -= 0.25f;
+            if (zoom < 0.f)
+                zoom = 0.f;
+            break;
+        case GLFW_KEY_PAGE_DOWN:
+            zoom += 0.25f;
+            break;
+        default:
+            break;
+    }
+}
+
+
+//========================================================================
+// Callback function for mouse button events
+//========================================================================
+
+void mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
+{
+    if (button != GLFW_MOUSE_BUTTON_LEFT)
+        return;
+
+    if (action == GLFW_PRESS)
+    {
+        glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
+        glfwGetCursorPos(window, &cursorX, &cursorY);
+    }
+    else
+        glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_NORMAL);
+}
+
+
+//========================================================================
+// Callback function for cursor motion events
+//========================================================================
+
+void cursor_position_callback(GLFWwindow* window, double x, double y)
+{
+    if (glfwGetInputMode(window, GLFW_CURSOR) == GLFW_CURSOR_DISABLED)
+    {
+        alpha += (GLfloat) (x - cursorX) / 10.f;
+        beta += (GLfloat) (y - cursorY) / 10.f;
+
+        cursorX = x;
+        cursorY = y;
+    }
+}
+
+
+//========================================================================
+// Callback function for scroll events
+//========================================================================
+
+void scroll_callback(GLFWwindow* window, double x, double y)
+{
+    zoom += (float) y / 4.f;
+    if (zoom < 0)
+        zoom = 0;
+}
+
+
+//========================================================================
+// Callback function for framebuffer resize events
+//========================================================================
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
+{
+    float ratio = 1.f;
+    mat4x4 projection;
+
+    if (height > 0)
+        ratio = (float) width / (float) height;
+
+    // Setup viewport
+    glViewport(0, 0, width, height);
+
+    // Change to the projection matrix and set our viewing volume
+    glMatrixMode(GL_PROJECTION);
+    mat4x4_perspective(projection,
+                       60.f * (float) M_PI / 180.f,
+                       ratio,
+                       1.f, 1024.f);
+    glLoadMatrixf((const GLfloat*) projection);
+}
+
+
+//========================================================================
+// main
+//========================================================================
+
+int main(int argc, char* argv[])
+{
+    GLFWwindow* window;
+    double t, dt_total, t_old;
+    int width, height;
+
+    glfwSetErrorCallback(error_callback);
+
+    if (!glfwInit())
+        exit(EXIT_FAILURE);
+
+    window = glfwCreateWindow(640, 480, "Wave Simulation", NULL, NULL);
+    if (!window)
+    {
+        glfwTerminate();
+        exit(EXIT_FAILURE);
+    }
+
+    glfwSetKeyCallback(window, key_callback);
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+    glfwSetMouseButtonCallback(window, mouse_button_callback);
+    glfwSetCursorPosCallback(window, cursor_position_callback);
+    glfwSetScrollCallback(window, scroll_callback);
+
+    glfwMakeContextCurrent(window);
+    gladLoadGL(glfwGetProcAddress);
+    glfwSwapInterval(1);
+
+    glfwGetFramebufferSize(window, &width, &height);
+    framebuffer_size_callback(window, width, height);
+
+    // Initialize OpenGL
+    init_opengl();
+
+    // Initialize simulation
+    init_vertices();
+    init_grid();
+    adjust_grid();
+
+    // Initialize timer
+    t_old = glfwGetTime() - 0.01;
+
+    while (!glfwWindowShouldClose(window))
+    {
+        t = glfwGetTime();
+        dt_total = t - t_old;
+        t_old = t;
+
+        // Safety - iterate if dt_total is too large
+        while (dt_total > 0.f)
+        {
+            // Select iteration time step
+            dt = dt_total > MAX_DELTA_T ? MAX_DELTA_T : dt_total;
+            dt_total -= dt;
+
+            // Calculate wave propagation
+            calc_grid();
+        }
+
+        // Compute height of each vertex
+        adjust_grid();
+
+        // Draw wave grid to OpenGL display
+        draw_scene(window);
+
+        glfwPollEvents();
+    }
+
+    glfwTerminate();
+    exit(EXIT_SUCCESS);
+}
+