initmain

1 files changed, 223 insertions, 0 deletions

diff --git a/main.c b/main.c
new file mode 100644
index 0000000..dc2c7e3
--- /dev/null
+++ b/main.c
@@ -0,0 +1,223 @@
+#include <glad/gl.h>
+#include <GLFW/glfw3.h>
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <math.h>
+
+#include <rt.h>
+
+#define RESOLUTION_X 800
+#define RESOLUTION_Y 600
+#define CAMERA_MOVE_SPEED 0.02
+#define CAMERA_ROTATE_SPEED 0.005
+
+const char* vertex_shader_source = 
+"#version 330 core\n"
+"layout (location = 0) in vec3 aPos;\n"
+"void main() {\n"
+"gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+"}\0";
+
+int u_resolution_location;
+
+double mouse_x = RESOLUTION_X / 2.0;
+double mouse_y = RESOLUTION_Y / 2.0;
+
+typedef struct {
+    float x;
+    float y;
+    float z;
+} Vec3;
+
+Vec3 vec_add(const Vec3 left, const Vec3 right) {
+    Vec3 result = {left.x + right.x, left.y + right.y, left.z + right.z};
+    return result;
+}
+
+Vec3 vec_sub(const Vec3 left, const Vec3 right) {
+    Vec3 result = {left.x - right.x, left.y - right.y, left.z - right.z};
+    return result;
+}
+
+Vec3 vec_mult_by_float(const Vec3 left, float right) {
+    Vec3 result = {left.x * right, left.y * right, left.z * right};
+    return result;
+}
+
+Vec3 vec_cross(const Vec3 left, const Vec3 right) {
+    Vec3 result = {left.y * right.z - left.z * right.y, left.z * right.x - left.x * right.z, left.x * right.y - left.y * right.x};
+    return result;
+}
+
+Vec3 vec_normalize(const Vec3 left) {
+    float length = sqrtf(left.x * left.x + left.y * left.y + left.z * left.z);
+    Vec3 result = {left.x / length, left.y / length, left.z / length};
+    return result;
+}
+
+typedef struct {
+    Vec3 position;
+    Vec3 look_at;
+    Vec3 vup;
+} Camera;
+
+Camera camera = {{0.0, 0.0, 0.0}, {0.0, 0.0, -1.0}, {0.0, 1.0, 0.0}};
+
+void on_resize(GLFWwindow* window, int width, int height) {
+    glViewport(0, 0, width, height);
+    glUniform2f(u_resolution_location, width, height);
+}
+
+void on_mouse_event(GLFWwindow* window, double x_position, double y_position) {
+    double delta_x = x_position - mouse_x;
+    double delta_y = mouse_y - y_position;
+    mouse_x = x_position;
+    mouse_y = y_position;
+    camera.look_at = vec_normalize(vec_add(camera.look_at, vec_mult_by_float(vec_cross(camera.look_at, camera.vup), (delta_x * CAMERA_ROTATE_SPEED))));
+    camera.look_at = vec_normalize(vec_add(camera.look_at, vec_mult_by_float(camera.vup, (delta_y * CAMERA_ROTATE_SPEED))));
+}
+
+int main(void) {
+    glfwInit();
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+#ifdef __APPLE__
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
+#endif
+
+    GLFWwindow* window = glfwCreateWindow(RESOLUTION_X, RESOLUTION_Y, "OpenGL", NULL, NULL);
+    if (window == NULL) {
+        fprintf(stderr, "Failed to create GLFW window.\n");
+        glfwTerminate();
+        return 1;
+    }
+    glfwMakeContextCurrent(window);
+    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);  
+
+    if (gladLoadGL(glfwGetProcAddress) == 0) {
+        fprintf(stderr, "Failed to initialise OpenGL context.\n");
+        glfwTerminate();
+        return 1;
+    }
+
+    glViewport(0, 0, RESOLUTION_X, RESOLUTION_Y);
+    glfwSetFramebufferSizeCallback(window, on_resize);
+    glfwSetCursorPosCallback(window, on_mouse_event);
+
+    int success;
+    unsigned int vertex_shader = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertex_shader, 1, &vertex_shader_source, NULL);
+    glCompileShader(vertex_shader);
+    glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &success);
+    if (!success) {
+        char info_log[512];
+        glGetShaderInfoLog(vertex_shader, 512, NULL, info_log);
+        fprintf(stderr, "Vertex shader compilation failed: %s", info_log);
+        glfwTerminate();
+        return 1;
+    }
+
+    unsigned int frag_shader = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(frag_shader, 1, &rt_frag_shader_source, NULL);
+    glCompileShader(frag_shader);
+    glGetShaderiv(frag_shader, GL_COMPILE_STATUS, &success);
+    if (!success) {
+        char info_log[512];
+        glGetShaderInfoLog(frag_shader, 512, NULL, info_log);
+        fprintf(stderr, "Fragment shader compilation failed: %s", info_log);
+        glfwTerminate();
+        return 1;
+    }
+
+    unsigned int program = glCreateProgram();
+    glAttachShader(program, vertex_shader);
+    glAttachShader(program, frag_shader);
+    glLinkProgram(program);
+    glGetProgramiv(program, GL_LINK_STATUS, &success);
+    if (!success) {
+        char info_log[512];
+        glGetProgramInfoLog(program, 512, NULL, info_log);
+        fprintf(stderr, "Program linking failed: %s", info_log);
+        glfwTerminate();
+        return 1;
+    }
+    // Pull uniforms into variables here.
+    u_resolution_location = glGetUniformLocation(program, "u_resolution");
+    int u_time_location = glGetUniformLocation(program, "u_time");
+    int u_camera_location_location = glGetUniformLocation(program, "u_camera_location");
+    int u_camera_lookat_location = glGetUniformLocation(program, "u_camera_lookat");
+    int u_camera_vup_location = glGetUniformLocation(program, "u_camera_vup");
+    glUseProgram(program);
+    // Define uniforms here.
+    glUniform2f(u_resolution_location, RESOLUTION_X, RESOLUTION_Y);
+    glUniform1f(u_time_location, 0.0);
+    glUniform3f(u_camera_location_location, camera.position.x, camera.position.y, camera.position.z);
+    Vec3 worldspace_look_at = vec_add(camera.position, camera.look_at);
+    glUniform3f(u_camera_lookat_location, worldspace_look_at.x, worldspace_look_at.y, worldspace_look_at.z);
+    glUniform3f(u_camera_vup_location, camera.vup.x, camera.vup.y, camera.vup.z);
+    glDeleteShader(vertex_shader);
+    glDeleteShader(frag_shader);
+
+    float rect_vertices[] = {
+         1.0,  1.0,  0.0,
+         1.0, -1.0,  0.0,
+        -1.0, -1.0,  0.0,
+        -1.0,  1.0,  0.0,
+    };
+
+    unsigned int triangle_draw_indices[] = {
+        0, 1, 3,
+        1, 2, 3
+    };
+
+    unsigned int vbo, vao, ebo;
+    glGenVertexArrays(1, &vao);
+    glGenBuffers(1, &vbo);
+    glGenBuffers(1, &ebo);
+    glBindVertexArray(vao);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(rect_vertices), rect_vertices, GL_STATIC_DRAW);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(triangle_draw_indices), triangle_draw_indices, GL_STATIC_DRAW);
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+    glEnableVertexAttribArray(0);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+    while (!glfwWindowShouldClose(window)) {
+        if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
+            glfwSetWindowShouldClose(window, true);
+        }
+        if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
+            camera.position = vec_add(camera.position, vec_mult_by_float(camera.look_at, CAMERA_MOVE_SPEED));
+            glUniform3f(u_camera_location_location, camera.position.x, camera.position.y, camera.position.z);
+        }
+        if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
+            camera.position = vec_sub(camera.position, vec_mult_by_float(camera.look_at, CAMERA_MOVE_SPEED));
+            glUniform3f(u_camera_location_location, camera.position.x, camera.position.y, camera.position.z);
+        }
+        if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
+            camera.position = vec_sub(camera.position, vec_mult_by_float(vec_normalize(vec_cross(camera.look_at, camera.vup)), CAMERA_MOVE_SPEED));
+            glUniform3f(u_camera_location_location, camera.position.x, camera.position.y, camera.position.z);
+        }
+        if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
+            camera.position = vec_add(camera.position, vec_mult_by_float(vec_normalize(vec_cross(camera.look_at, camera.vup)), CAMERA_MOVE_SPEED));
+            glUniform3f(u_camera_location_location, camera.position.x, camera.position.y, camera.position.z);
+        }
+        Vec3 worldspace_look_at = vec_add(camera.position, camera.look_at);
+        glUniform3f(u_camera_lookat_location, worldspace_look_at.x, worldspace_look_at.y, worldspace_look_at.z);
+        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+        glUniform1f(u_time_location, glfwGetTime());
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+    }
+
+    glDeleteVertexArrays(1, &vao);
+    glDeleteBuffers(1, &vbo);
+    glDeleteBuffers(1, &ebo);
+    glDeleteProgram(program);
+    glfwTerminate();
+    return 0;
+}
\ No newline at end of file