main.cpp

#include "glm/gtc/quaternion.hpp"
#define GL_SILENCE_DEPRECATION
#include "shader.hpp"
#include "stb_image.h"
#include <cmath>
#include <fstream>
#include <glad/glad.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <iostream>

#include <GLFW/glfw3.h>

void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void processInput(GLFWwindow *window);
void mouse_callback(GLFWwindow *window, double xpos, double ypos);

// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);
glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);

float deltaTime = 0.0f;
float lastFrame = 0.0f;

float lastX = 400, lastY = 300, yaw = -90.0f, pitch = 0.0f;
bool firstMouse = true;

int main() {
  // glfw: initialize and configure
  // ------------------------------
  glfwInit();
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

#ifdef __APPLE__
  glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

  // glfw window creation
  // --------------------
  GLFWwindow *window =
      glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
  if (window == NULL) {
    std::cout << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    return -1;
  }
  glfwMakeContextCurrent(window);
  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
  glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
  glfwSetCursorPosCallback(window, mouse_callback);

  // glad: load all OpenGL function pointers
  // ---------------------------------------
  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
    std::cout << "Failed to initialize GLAD" << std::endl;
    return -1;
  }

  Shader ourShader("./shaders/textures/shader.vs",
                   "./shaders/textures/shader.fs");

  float vertices[] = {
      -0.5f, -0.5f, -0.5f, 0.0f, 0.0f, 0.5f,  -0.5f, -0.5f, 1.0f, 0.0f,
      0.5f,  0.5f,  -0.5f, 1.0f, 1.0f, 0.5f,  0.5f,  -0.5f, 1.0f, 1.0f,
      -0.5f, 0.5f,  -0.5f, 0.0f, 1.0f, -0.5f, -0.5f, -0.5f, 0.0f, 0.0f,

      -0.5f, -0.5f, 0.5f,  0.0f, 0.0f, 0.5f,  -0.5f, 0.5f,  1.0f, 0.0f,
      0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
      -0.5f, 0.5f,  0.5f,  0.0f, 1.0f, -0.5f, -0.5f, 0.5f,  0.0f, 0.0f,

      -0.5f, 0.5f,  0.5f,  1.0f, 0.0f, -0.5f, 0.5f,  -0.5f, 1.0f, 1.0f,
      -0.5f, -0.5f, -0.5f, 0.0f, 1.0f, -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
      -0.5f, -0.5f, 0.5f,  0.0f, 0.0f, -0.5f, 0.5f,  0.5f,  1.0f, 0.0f,

      0.5f,  0.5f,  0.5f,  1.0f, 0.0f, 0.5f,  0.5f,  -0.5f, 1.0f, 1.0f,
      0.5f,  -0.5f, -0.5f, 0.0f, 1.0f, 0.5f,  -0.5f, -0.5f, 0.0f, 1.0f,
      0.5f,  -0.5f, 0.5f,  0.0f, 0.0f, 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

      -0.5f, -0.5f, -0.5f, 0.0f, 1.0f, 0.5f,  -0.5f, -0.5f, 1.0f, 1.0f,
      0.5f,  -0.5f, 0.5f,  1.0f, 0.0f, 0.5f,  -0.5f, 0.5f,  1.0f, 0.0f,
      -0.5f, -0.5f, 0.5f,  0.0f, 0.0f, -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,

      -0.5f, 0.5f,  -0.5f, 0.0f, 1.0f, 0.5f,  0.5f,  -0.5f, 1.0f, 1.0f,
      0.5f,  0.5f,  0.5f,  1.0f, 0.0f, 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
      -0.5f, 0.5f,  0.5f,  0.0f, 0.0f, -0.5f, 0.5f,  -0.5f, 0.0f, 1.0f};

  unsigned int indices[] = {
      0, 1, 3, // first triangle
      1, 2, 3  // second triangle
  };

  glm::vec3 cubePositions[] = {
      glm::vec3(0.0f, 0.0f, 0.0f),    glm::vec3(2.0f, 5.0f, -15.0f),
      glm::vec3(-1.5f, -2.2f, -2.5f), glm::vec3(-3.8f, -2.0f, -12.3f),
      glm::vec3(2.4f, -0.4f, -3.5f),  glm::vec3(-1.7f, 3.0f, -7.5f),
      glm::vec3(1.3f, -2.0f, -2.5f),  glm::vec3(1.5f, 2.0f, -2.5f),
      glm::vec3(1.5f, 0.2f, -1.5f),   glm::vec3(-1.3f, 1.0f, -1.5f)};

  unsigned int VBO, VAO;
  glGenVertexArrays(1, &VAO);
  glGenBuffers(1, &VBO);
  // bind the Vertex Array Object first, then bind and set vertex buffer(s), and
  // then configure vertex attributes(s).
  glBindVertexArray(VAO);

  glBindBuffer(GL_ARRAY_BUFFER, VBO);
  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
  glEnableVertexAttribArray(0);

  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float),
                        (void *)(3 * sizeof(float)));
  glEnableVertexAttribArray(1);

  // render loop
  // -----------
  // glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

  unsigned int 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);
  // load and generate the texture
  int width, height, nrChannels;
  unsigned char *data = stbi_load("./assets/textures/container.jpg", &width,
                                  &height, &nrChannels, 0);
  if (data) {
    glBindTexture(GL_TEXTURE_2D, texture1);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB,
                 GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);
  } else {
    std::cout << "Failed to load texture" << std::endl;
  }
  stbi_image_free(data);

  glGenTextures(1, &texture2);
  glBindTexture(GL_TEXTURE_2D, texture2);
  // set the texture wrapping parameters
  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);
  stbi_set_flip_vertically_on_load(true);
  data = stbi_load("./assets/textures/awesomeface.png", &width, &height,
                   &nrChannels, 0);

  if (data) {
    glBindTexture(GL_TEXTURE_2D, texture2);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);
  } else {
    std::cout << "Failed to load texture" << std::endl;
  }
  stbi_image_free(data);

  ourShader.use();
  glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0);
  ourShader.setInt("texture2", 1);
  glEnable(GL_DEPTH_TEST);
  while (!glfwWindowShouldClose(window)) {
    // input
    // -----
    processInput(window);

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

    // draw our first triangle
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture1);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, texture2);

    ourShader.use();
    glBindVertexArray(VAO);

    glm::mat4 view;
    view = glm::lookAt(cameraPos, cameraFront + cameraPos, cameraUp);

    glm::mat4 projection =
        glm::perspective(glm::radians(45.0f), 800.0f / 600.0f, 0.1f, 100.0f);
    ourShader.setMat4("projection", projection);
    ourShader.setMat4("view", view);

    for (int i = 0; i < 10; i++) {
      glm::mat4 model = glm::mat4(1.0f);
      model = glm::translate(model, cubePositions[i]);
      float angle = 20.0f * i;
      if (i % 3 == 0)
        angle = 20.0f * glfwGetTime();
      model =
          glm::rotate(model, glm::radians(angle), glm::vec3(0.5f, 1.0f, 0.0f));

      ourShader.setMat4("model", model);
      glDrawArrays(GL_TRIANGLES, 0, 36);
    }

    // glBindVertexArray(0); // no need to unbind it every time

    // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved
    // etc.)
    // -------------------------------------------------------------------------------
    glfwSwapBuffers(window);
    glfwPollEvents();
  }

  // optional: de-allocate all resources once they've outlived their purpose:
  // ------------------------------------------------------------------------
  glDeleteVertexArrays(1, &VAO);
  glDeleteBuffers(1, &VBO);

  // glfw: terminate, clearing all previously allocated GLFW resources.
  // ------------------------------------------------------------------
  glfwTerminate();
  return 0;
}

// process all input: query GLFW whether relevant keys are pressed/released this
// frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void processInput(GLFWwindow *window) {
  if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    glfwSetWindowShouldClose(window, true);
  deltaTime = glfwGetTime() - lastFrame;
  lastFrame = glfwGetTime();
  const float cameraSpeed = 2.5f * deltaTime;
  if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
    cameraPos += cameraSpeed * cameraFront;
  if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
    cameraPos -= cameraSpeed * cameraFront;
  if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    cameraPos -=
        glm::normalize(glm::cross(cameraFront, cameraUp)) * cameraSpeed;
  if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
    cameraPos +=
        glm::normalize(glm::cross(cameraFront, cameraUp)) * cameraSpeed;
}

// glfw: whenever the window size changed (by OS or user resize) this callback
// function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
  // make sure the viewport matches the new window dimensions; note that width
  // and height will be significantly larger than specified on retina displays.
  glViewport(0, 0, width, height);
}

void mouse_callback(GLFWwindow *window, double xpos, double ypos) {
  if (firstMouse) {
    lastX = xpos;
    lastY = ypos;
    firstMouse = false;
  }

  float xoffset = xpos - lastX;
  float yoffset = lastY - ypos;
  lastX = xpos;
  lastY = ypos;

  float sensitivity = 0.1f;
  xoffset *= sensitivity;
  yoffset *= sensitivity;

  yaw += xoffset;
  pitch += yoffset;

  if (pitch > 89.0f)
    pitch = 89.0f;
  if (pitch < -89.0f)
    pitch = -89.0f;

  glm::vec3 direction;
  direction.x = cos(glm::radians(yaw)) * cos(glm::radians(pitch));
  direction.y = sin(glm::radians(pitch));
  direction.z = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
  cameraFront = glm::normalize(direction);
}