opengl-playground/main.c

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <math.h>
#include "glad/glad.h"
#include <GLFW/glfw3.h>
#include "lib.h"
#include "libs/cglm/cglm.h"

#define STB_IMAGE_IMPLEMENTATION
#define STBI_FAILURE_USERMSG
#include "stb_image.h"

int SCREEN_WIDTH = 1024;
int SCREEN_HEIGHT = 768;

vec2 direction = {0};

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    (void)window;
    glViewport(0, 0, width, height);
    SCREEN_WIDTH = width;
    SCREEN_HEIGHT = height;
}

void processInput(GLFWwindow *window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
    direction[0] = 0;
    direction[1] = 0;
    if (glfwGetKey(window, GLFW_KEY_LEFT) == GLFW_PRESS) {
        direction[0] =  1;
    }
    if (glfwGetKey(window, GLFW_KEY_RIGHT) == GLFW_PRESS) {
        direction[0] = -1;
    }
    if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS) {
        direction[1] = -1;
    }
    if (glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS) {
        direction[1] =  1;
    }
}

int main(void) {
    glfwInit();

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window =
        checkPtr(glfwCreateWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "Learn OpenGL", NULL, NULL),
                 "Error creating GLFW window");
    if (window == NULL) glfwTerminate();

    glfwMakeContextCurrent(window);

    checkCode(gladLoadGLLoader((GLADloadproc)glfwGetProcAddress), "Error initializing GLAD");

    glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);

    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    GLuint shaderProgram =
        compileShaderProgram("shaders/main.vert", "shaders/main.frag", NULL);

    stbi_set_flip_vertically_on_load(true);
    GLuint texture1, texture2;
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);
    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_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    int w1, h1, c1;
    unsigned char* container = stbi_load("container.jpg", &w1, &h1, &c1, 0);
    if (container == NULL) {
        fprintf(stderr, "Failed to load image\n");
        exit(-1);
    }
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w1, h1, 0, GL_RGB,  GL_UNSIGNED_BYTE, container);
    glGenerateMipmap(GL_TEXTURE_2D);

    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);
    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_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    int w2, h2, c2;
    unsigned char* smiley = stbi_load("awesomeface.png", &w2, &h2, &c2, 0);
    if (smiley == NULL) {
        fprintf(stderr, "Failed to load image\n");
        exit(-1);
    }
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w2, h2, 0, GL_RGBA, GL_UNSIGNED_BYTE, smiley);
    glGenerateMipmap(GL_TEXTURE_2D);

    stbi_image_free(container);
    stbi_image_free(smiley);

    glEnable(GL_DEPTH_TEST);

    GLuint vaos[2];
    GLuint vbos[2];
    // unsigned int EBO;
    glGenVertexArrays(2, vaos);
    // glGenBuffers(1, &EBO);
    glGenBuffers(2, vbos);

    glBindVertexArray(vaos[0]);
    glBindBuffer(GL_ARRAY_BUFFER, vbos[0]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVerts), cubeVerts, GL_STATIC_DRAW);

    // glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    // glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3*sizeof(float)));
    glEnableVertexAttribArray(1);
    // glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6*sizeof(float)));
    // glEnableVertexAttribArray(2);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    glUseProgram(shaderProgram);
    int t1Loc = glGetUniformLocation(shaderProgram, "t1");
    glUniform1i(t1Loc, 0);
    int t2Loc = glGetUniformLocation(shaderProgram, "t2");
    glUniform1i(t2Loc, 1);

    mat4 view;
    glm_mat4_identity(view);
    glm_translate(view, (vec3){0.0f, 0.0f, -0.6f});
    mat4 projection;
    glm_mat4_identity(projection);
    float aspectRatio = (float)SCREEN_WIDTH / (float)SCREEN_HEIGHT;
    glm_perspective(45.0f, aspectRatio, 0.1f, 100.0f, projection);

    int cubeCount = 10;
    vec3 cubePositions[cubeCount];
    srand(arc4random());
    for (int i = 0; i < cubeCount; i++) {
        float x = ((float)rand()/(float)(RAND_MAX)) * 5.0f - 2.5f;
        float y = ((float)rand()/(float)(RAND_MAX)) * 5.0f - 2.5f;
        float z = ((float)rand()/(float)(RAND_MAX)) * 5.0f - 2.5f;
        cubePositions[i][0] = x;
        cubePositions[i][1] = y;
        cubePositions[i][2] = z;
    }

    float lastFrame = 0.0f;
    while (!glfwWindowShouldClose(window)) {
        float currentFrame = (float)glfwGetTime();
        float dt = currentFrame - lastFrame;
        lastFrame = currentFrame;
        processInput(window);

        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // float spin = (sin(currentFrame) / 2.0f) + 0.5f;
        // printf("%f\n", deltaTime);

        float speed = 0.5 * dt;
        glm_translate(view, (vec3){direction[0] * speed, 0.0f, direction[1] * speed});
        int matrixLocation;
        matrixLocation = glGetUniformLocation(shaderProgram, "view");
        glUniformMatrix4fv(matrixLocation, 1, GL_FALSE, view[0]);
        matrixLocation = glGetUniformLocation(shaderProgram, "projection");
        glUniformMatrix4fv(matrixLocation, 1, GL_FALSE, projection[0]);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);

        glBindVertexArray(vaos[0]);
        // glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        for (int i = 0; i < cubeCount; i++) {
            mat4 model;
            glm_mat4_identity(model);
            glm_scale(model, (vec3){0.1f, 0.1f, 0.1f});
            glm_translate(model, cubePositions[i]);
            glm_rotate(model, (i+1) * currentFrame, (vec3){1.0f, 1.0f, 0.0f});

            matrixLocation = glGetUniformLocation(shaderProgram, "model");
            glUniformMatrix4fv(matrixLocation, 1, GL_FALSE, model[0]);

            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(2, vaos);
    glDeleteBuffers(2, vbos);
    glDeleteProgram(shaderProgram);
    glfwTerminate();
    return 0;
}