add glfw library

1 files changed, 512 insertions, 0 deletions

diff --git a/libs/glfw-3.3.8/examples/heightmap.c b/libs/glfw-3.3.8/examples/heightmap.c
new file mode 100644
index 0000000..988dd0b
--- /dev/null
+++ b/libs/glfw-3.3.8/examples/heightmap.c
@@ -0,0 +1,512 @@
+//========================================================================
+// Heightmap example program using OpenGL 3 core profile
+// Copyright (c) 2010 Olivier Delannoy
+//
+// 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.
+//
+//========================================================================
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <assert.h>
+#include <stddef.h>
+
+#include <glad/gl.h>
+#define GLFW_INCLUDE_NONE
+#include <GLFW/glfw3.h>
+
+/* Map height updates */
+#define MAX_CIRCLE_SIZE (5.0f)
+#define MAX_DISPLACEMENT (1.0f)
+#define DISPLACEMENT_SIGN_LIMIT (0.3f)
+#define MAX_ITER (200)
+#define NUM_ITER_AT_A_TIME (1)
+
+/* Map general information */
+#define MAP_SIZE (10.0f)
+#define MAP_NUM_VERTICES (80)
+#define MAP_NUM_TOTAL_VERTICES (MAP_NUM_VERTICES*MAP_NUM_VERTICES)
+#define MAP_NUM_LINES (3* (MAP_NUM_VERTICES - 1) * (MAP_NUM_VERTICES - 1) + \
+               2 * (MAP_NUM_VERTICES - 1))
+
+
+/**********************************************************************
+ * Default shader programs
+ *********************************************************************/
+
+static const char* vertex_shader_text =
+"#version 150\n"
+"uniform mat4 project;\n"
+"uniform mat4 modelview;\n"
+"in float x;\n"
+"in float y;\n"
+"in float z;\n"
+"\n"
+"void main()\n"
+"{\n"
+"   gl_Position = project * modelview * vec4(x, y, z, 1.0);\n"
+"}\n";
+
+static const char* fragment_shader_text =
+"#version 150\n"
+"out vec4 color;\n"
+"void main()\n"
+"{\n"
+"    color = vec4(0.2, 1.0, 0.2, 1.0); \n"
+"}\n";
+
+/**********************************************************************
+ * Values for shader uniforms
+ *********************************************************************/
+
+/* Frustum configuration */
+static GLfloat view_angle = 45.0f;
+static GLfloat aspect_ratio = 4.0f/3.0f;
+static GLfloat z_near = 1.0f;
+static GLfloat z_far = 100.f;
+
+/* Projection matrix */
+static GLfloat projection_matrix[16] = {
+    1.0f, 0.0f, 0.0f, 0.0f,
+    0.0f, 1.0f, 0.0f, 0.0f,
+    0.0f, 0.0f, 1.0f, 0.0f,
+    0.0f, 0.0f, 0.0f, 1.0f
+};
+
+/* Model view matrix */
+static GLfloat modelview_matrix[16] = {
+    1.0f, 0.0f, 0.0f, 0.0f,
+    0.0f, 1.0f, 0.0f, 0.0f,
+    0.0f, 0.0f, 1.0f, 0.0f,
+    0.0f, 0.0f, 0.0f, 1.0f
+};
+
+/**********************************************************************
+ * Heightmap vertex and index data
+ *********************************************************************/
+
+static GLfloat map_vertices[3][MAP_NUM_TOTAL_VERTICES];
+static GLuint  map_line_indices[2*MAP_NUM_LINES];
+
+/* Store uniform location for the shaders
+ * Those values are setup as part of the process of creating
+ * the shader program. They should not be used before creating
+ * the program.
+ */
+static GLuint mesh;
+static GLuint mesh_vbo[4];
+
+/**********************************************************************
+ * OpenGL helper functions
+ *********************************************************************/
+
+/* Creates a shader object of the specified type using the specified text
+ */
+static GLuint make_shader(GLenum type, const char* text)
+{
+    GLuint shader;
+    GLint shader_ok;
+    GLsizei log_length;
+    char info_log[8192];
+
+    shader = glCreateShader(type);
+    if (shader != 0)
+    {
+        glShaderSource(shader, 1, (const GLchar**)&text, NULL);
+        glCompileShader(shader);
+        glGetShaderiv(shader, GL_COMPILE_STATUS, &shader_ok);
+        if (shader_ok != GL_TRUE)
+        {
+            fprintf(stderr, "ERROR: Failed to compile %s shader\n", (type == GL_FRAGMENT_SHADER) ? "fragment" : "vertex" );
+            glGetShaderInfoLog(shader, 8192, &log_length,info_log);
+            fprintf(stderr, "ERROR: \n%s\n\n", info_log);
+            glDeleteShader(shader);
+            shader = 0;
+        }
+    }
+    return shader;
+}
+
+/* Creates a program object using the specified vertex and fragment text
+ */
+static GLuint make_shader_program(const char* vs_text, const char* fs_text)
+{
+    GLuint program = 0u;
+    GLint program_ok;
+    GLuint vertex_shader = 0u;
+    GLuint fragment_shader = 0u;
+    GLsizei log_length;
+    char info_log[8192];
+
+    vertex_shader = make_shader(GL_VERTEX_SHADER, vs_text);
+    if (vertex_shader != 0u)
+    {
+        fragment_shader = make_shader(GL_FRAGMENT_SHADER, fs_text);
+        if (fragment_shader != 0u)
+        {
+            /* make the program that connect the two shader and link it */
+            program = glCreateProgram();
+            if (program != 0u)
+            {
+                /* attach both shader and link */
+                glAttachShader(program, vertex_shader);
+                glAttachShader(program, fragment_shader);
+                glLinkProgram(program);
+                glGetProgramiv(program, GL_LINK_STATUS, &program_ok);
+
+                if (program_ok != GL_TRUE)
+                {
+                    fprintf(stderr, "ERROR, failed to link shader program\n");
+                    glGetProgramInfoLog(program, 8192, &log_length, info_log);
+                    fprintf(stderr, "ERROR: \n%s\n\n", info_log);
+                    glDeleteProgram(program);
+                    glDeleteShader(fragment_shader);
+                    glDeleteShader(vertex_shader);
+                    program = 0u;
+                }
+            }
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Unable to load fragment shader\n");
+            glDeleteShader(vertex_shader);
+        }
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to load vertex shader\n");
+    }
+    return program;
+}
+
+/**********************************************************************
+ * Geometry creation functions
+ *********************************************************************/
+
+/* Generate vertices and indices for the heightmap
+ */
+static void init_map(void)
+{
+    int i;
+    int j;
+    int k;
+    GLfloat step = MAP_SIZE / (MAP_NUM_VERTICES - 1);
+    GLfloat x = 0.0f;
+    GLfloat z = 0.0f;
+    /* Create a flat grid */
+    k = 0;
+    for (i = 0 ; i < MAP_NUM_VERTICES ; ++i)
+    {
+        for (j = 0 ; j < MAP_NUM_VERTICES ; ++j)
+        {
+            map_vertices[0][k] = x;
+            map_vertices[1][k] = 0.0f;
+            map_vertices[2][k] = z;
+            z += step;
+            ++k;
+        }
+        x += step;
+        z = 0.0f;
+    }
+#if DEBUG_ENABLED
+    for (i = 0 ; i < MAP_NUM_TOTAL_VERTICES ; ++i)
+    {
+        printf ("Vertice %d (%f, %f, %f)\n",
+                i, map_vertices[0][i], map_vertices[1][i], map_vertices[2][i]);
+
+    }
+#endif
+    /* create indices */
+    /* line fan based on i
+     * i+1
+     * |  / i + n + 1
+     * | /
+     * |/
+     * i --- i + n
+     */
+
+    /* close the top of the square */
+    k = 0;
+    for (i = 0 ; i < MAP_NUM_VERTICES  -1 ; ++i)
+    {
+        map_line_indices[k++] = (i + 1) * MAP_NUM_VERTICES -1;
+        map_line_indices[k++] = (i + 2) * MAP_NUM_VERTICES -1;
+    }
+    /* close the right of the square */
+    for (i = 0 ; i < MAP_NUM_VERTICES -1 ; ++i)
+    {
+        map_line_indices[k++] = (MAP_NUM_VERTICES - 1) * MAP_NUM_VERTICES + i;
+        map_line_indices[k++] = (MAP_NUM_VERTICES - 1) * MAP_NUM_VERTICES + i + 1;
+    }
+
+    for (i = 0 ; i < (MAP_NUM_VERTICES - 1) ; ++i)
+    {
+        for (j = 0 ; j < (MAP_NUM_VERTICES - 1) ; ++j)
+        {
+            int ref = i * (MAP_NUM_VERTICES) + j;
+            map_line_indices[k++] = ref;
+            map_line_indices[k++] = ref + 1;
+
+            map_line_indices[k++] = ref;
+            map_line_indices[k++] = ref + MAP_NUM_VERTICES;
+
+            map_line_indices[k++] = ref;
+            map_line_indices[k++] = ref + MAP_NUM_VERTICES + 1;
+        }
+    }
+
+#ifdef DEBUG_ENABLED
+    for (k = 0 ; k < 2 * MAP_NUM_LINES ; k += 2)
+    {
+        int beg, end;
+        beg = map_line_indices[k];
+        end = map_line_indices[k+1];
+        printf ("Line %d: %d -> %d (%f, %f, %f) -> (%f, %f, %f)\n",
+                k / 2, beg, end,
+                map_vertices[0][beg], map_vertices[1][beg], map_vertices[2][beg],
+                map_vertices[0][end], map_vertices[1][end], map_vertices[2][end]);
+    }
+#endif
+}
+
+static void generate_heightmap__circle(float* center_x, float* center_y,
+        float* size, float* displacement)
+{
+    float sign;
+    /* random value for element in between [0-1.0] */
+    *center_x = (MAP_SIZE * rand()) / (float) RAND_MAX;
+    *center_y = (MAP_SIZE * rand()) / (float) RAND_MAX;
+    *size = (MAX_CIRCLE_SIZE * rand()) / (float) RAND_MAX;
+    sign = (1.0f * rand()) / (float) RAND_MAX;
+    sign = (sign < DISPLACEMENT_SIGN_LIMIT) ? -1.0f : 1.0f;
+    *displacement = (sign * (MAX_DISPLACEMENT * rand())) / (float) RAND_MAX;
+}
+
+/* Run the specified number of iterations of the generation process for the
+ * heightmap
+ */
+static void update_map(int num_iter)
+{
+    assert(num_iter > 0);
+    while(num_iter)
+    {
+        /* center of the circle */
+        float center_x;
+        float center_z;
+        float circle_size;
+        float disp;
+        size_t ii;
+        generate_heightmap__circle(&center_x, &center_z, &circle_size, &disp);
+        disp = disp / 2.0f;
+        for (ii = 0u ; ii < MAP_NUM_TOTAL_VERTICES ; ++ii)
+        {
+            GLfloat dx = center_x - map_vertices[0][ii];
+            GLfloat dz = center_z - map_vertices[2][ii];
+            GLfloat pd = (2.0f * (float) sqrt((dx * dx) + (dz * dz))) / circle_size;
+            if (fabs(pd) <= 1.0f)
+            {
+                /* tx,tz is within the circle */
+                GLfloat new_height = disp + (float) (cos(pd*3.14f)*disp);
+                map_vertices[1][ii] += new_height;
+            }
+        }
+        --num_iter;
+    }
+}
+
+/**********************************************************************
+ * OpenGL helper functions
+ *********************************************************************/
+
+/* Create VBO, IBO and VAO objects for the heightmap geometry and bind them to
+ * the specified program object
+ */
+static void make_mesh(GLuint program)
+{
+    GLuint attrloc;
+
+    glGenVertexArrays(1, &mesh);
+    glGenBuffers(4, mesh_vbo);
+    glBindVertexArray(mesh);
+    /* Prepare the data for drawing through a buffer inidices */
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh_vbo[3]);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLuint)* MAP_NUM_LINES * 2, map_line_indices, GL_STATIC_DRAW);
+
+    /* Prepare the attributes for rendering */
+    attrloc = glGetAttribLocation(program, "x");
+    glBindBuffer(GL_ARRAY_BUFFER, mesh_vbo[0]);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * MAP_NUM_TOTAL_VERTICES, &map_vertices[0][0], GL_STATIC_DRAW);
+    glEnableVertexAttribArray(attrloc);
+    glVertexAttribPointer(attrloc, 1, GL_FLOAT, GL_FALSE, 0, 0);
+
+    attrloc = glGetAttribLocation(program, "z");
+    glBindBuffer(GL_ARRAY_BUFFER, mesh_vbo[2]);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * MAP_NUM_TOTAL_VERTICES, &map_vertices[2][0], GL_STATIC_DRAW);
+    glEnableVertexAttribArray(attrloc);
+    glVertexAttribPointer(attrloc, 1, GL_FLOAT, GL_FALSE, 0, 0);
+
+    attrloc = glGetAttribLocation(program, "y");
+    glBindBuffer(GL_ARRAY_BUFFER, mesh_vbo[1]);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * MAP_NUM_TOTAL_VERTICES, &map_vertices[1][0], GL_DYNAMIC_DRAW);
+    glEnableVertexAttribArray(attrloc);
+    glVertexAttribPointer(attrloc, 1, GL_FLOAT, GL_FALSE, 0, 0);
+}
+
+/* Update VBO vertices from source data
+ */
+static void update_mesh(void)
+{
+    glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(GLfloat) * MAP_NUM_TOTAL_VERTICES, &map_vertices[1][0]);
+}
+
+/**********************************************************************
+ * GLFW callback functions
+ *********************************************************************/
+
+static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
+{
+    switch(key)
+    {
+        case GLFW_KEY_ESCAPE:
+            /* Exit program on Escape */
+            glfwSetWindowShouldClose(window, GLFW_TRUE);
+            break;
+    }
+}
+
+static void error_callback(int error, const char* description)
+{
+    fprintf(stderr, "Error: %s\n", description);
+}
+
+int main(int argc, char** argv)
+{
+    GLFWwindow* window;
+    int iter;
+    double dt;
+    double last_update_time;
+    int frame;
+    float f;
+    GLint uloc_modelview;
+    GLint uloc_project;
+    int width, height;
+
+    GLuint shader_program;
+
+    glfwSetErrorCallback(error_callback);
+
+    if (!glfwInit())
+        exit(EXIT_FAILURE);
+
+    glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);
+
+    window = glfwCreateWindow(800, 600, "GLFW OpenGL3 Heightmap demo", NULL, NULL);
+    if (! window )
+    {
+        glfwTerminate();
+        exit(EXIT_FAILURE);
+    }
+
+    /* Register events callback */
+    glfwSetKeyCallback(window, key_callback);
+
+    glfwMakeContextCurrent(window);
+    gladLoadGL(glfwGetProcAddress);
+
+    /* Prepare opengl resources for rendering */
+    shader_program = make_shader_program(vertex_shader_text, fragment_shader_text);
+
+    if (shader_program == 0u)
+    {
+        glfwTerminate();
+        exit(EXIT_FAILURE);
+    }
+
+    glUseProgram(shader_program);
+    uloc_project   = glGetUniformLocation(shader_program, "project");
+    uloc_modelview = glGetUniformLocation(shader_program, "modelview");
+
+    /* Compute the projection matrix */
+    f = 1.0f / tanf(view_angle / 2.0f);
+    projection_matrix[0]  = f / aspect_ratio;
+    projection_matrix[5]  = f;
+    projection_matrix[10] = (z_far + z_near)/ (z_near - z_far);
+    projection_matrix[11] = -1.0f;
+    projection_matrix[14] = 2.0f * (z_far * z_near) / (z_near - z_far);
+    glUniformMatrix4fv(uloc_project, 1, GL_FALSE, projection_matrix);
+
+    /* Set the camera position */
+    modelview_matrix[12]  = -5.0f;
+    modelview_matrix[13]  = -5.0f;
+    modelview_matrix[14]  = -20.0f;
+    glUniformMatrix4fv(uloc_modelview, 1, GL_FALSE, modelview_matrix);
+
+    /* Create mesh data */
+    init_map();
+    make_mesh(shader_program);
+
+    /* Create vao + vbo to store the mesh */
+    /* Create the vbo to store all the information for the grid and the height */
+
+    /* setup the scene ready for rendering */
+    glfwGetFramebufferSize(window, &width, &height);
+    glViewport(0, 0, width, height);
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+
+    /* main loop */
+    frame = 0;
+    iter = 0;
+    last_update_time = glfwGetTime();
+
+    while (!glfwWindowShouldClose(window))
+    {
+        ++frame;
+        /* render the next frame */
+        glClear(GL_COLOR_BUFFER_BIT);
+        glDrawElements(GL_LINES, 2* MAP_NUM_LINES , GL_UNSIGNED_INT, 0);
+
+        /* display and process events through callbacks */
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+        /* Check the frame rate and update the heightmap if needed */
+        dt = glfwGetTime();
+        if ((dt - last_update_time) > 0.2)
+        {
+            /* generate the next iteration of the heightmap */
+            if (iter < MAX_ITER)
+            {
+                update_map(NUM_ITER_AT_A_TIME);
+                update_mesh();
+                iter += NUM_ITER_AT_A_TIME;
+            }
+            last_update_time = dt;
+            frame = 0;
+        }
+    }
+
+    glfwTerminate();
+    exit(EXIT_SUCCESS);
+}
+