main.cpp

#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include <iostream>

#include "utilities.h"
#include "shader.h"
#include "camera.h"
#include "model.h"

GLFWwindow* initWindow();
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void processInput(GLFWwindow *window);
unsigned int loadTexture(const char *path);
unsigned int loadCubemap(std::vector<std::string> faces);

// settings
const unsigned int SCR_WIDTH = 1200;
const unsigned int SCR_HEIGHT = 800;

// camera
Camera camera(glm::vec3(-2, 4, 8), glm::vec3(0, 1, 0), -77.0f, -16.0f);
float lastX = SCR_WIDTH / 2.0f;
float lastY = SCR_HEIGHT / 2.0f;
bool firstMouse = true;

// timing
float deltaTime = 0.0f;	// time between current frame and last frame
float lastFrame = 0.0f;

// wireframe mode
bool wireframe = false;

int main()
{
    GLFWwindow* window = initWindow();

    glEnable(GL_DEPTH_TEST);


    Shader *basicShader = new Shader("shaders/basic.vert", "shaders/basic.frag");
    Model *model = new Model("teapot.obj");
    model->setupBuffers();

    // render loop
    // -----------
    glm::mat4 modelMat = glm::mat4(1);
    glm::mat4 view;
    glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);

    glm::vec3 lightPos{1.0f, 2.0f, 1.0f};

    while (!glfwWindowShouldClose(window))
    {
        float currentFrame = glfwGetTime();
        deltaTime = currentFrame - lastFrame;
        lastFrame = currentFrame;
        processInput(window);
        // bootleg testing
        if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS){
            fprintf(stderr, "Pressed up, attempting to collapse mesh!\n");
            model->collapseMeshQEM();
        }

        glClearColor(0.82, 0.93, 0.99, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        view = camera.GetViewMatrix();
        glm::vec3 camPos = camera.Position;

        glm::mat4 modelView = view * modelMat;
        glm::mat4 normalMatrix = glm::inverse(glm::transpose(modelView));

        basicShader->use();

        basicShader->setMat4("model", modelMat);
        basicShader->setMat4("view", view);
        basicShader->setMat4("projection", projection);
        basicShader->setMat4("normalMatrix", normalMatrix);

        basicShader->setVec3("lightPos", lightPos);
        basicShader->setVec3("eyePos", camPos);

        // Draw the model
        model->draw();

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

    model->deleteGLResources();
    delete model;
    delete basicShader;

    // 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);

    if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
        camera.ProcessKeyboard(FORWARD, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
        camera.ProcessKeyboard(BACKWARD, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
        camera.ProcessKeyboard(LEFT, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
        camera.ProcessKeyboard(RIGHT, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_SPACE) == GLFW_PRESS)
        fprintf(stderr, "Camera position: %f, %f, %f\nCamera yaw, pitch: %f, %f\n", camera.Position.x, camera.Position.y, camera.Position.z, camera.Yaw, camera.Pitch);
    if (glfwGetKey(window, GLFW_KEY_M) == GLFW_PRESS) {
        // Toggle wireframe mode
        glPolygonMode( GL_FRONT_AND_BACK, wireframe ? GL_LINE :  GL_FILL);
        wireframe = !wireframe;
    }
}

// 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);
}


// glfw: whenever the mouse moves, this callback is called
// -------------------------------------------------------
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; // reversed since y-coordinates go from bottom to top

    lastX = xpos;
    lastY = ypos;

    camera.ProcessMouseMovement(xoffset, yoffset);
}

// glfw: whenever the mouse scroll wheel scrolls, this callback is called
// ----------------------------------------------------------------------
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
    camera.ProcessMouseScroll(yoffset);
}


GLFWwindow* initWindow() {
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    // 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 NULL;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    glfwSetCursorPosCallback(window, mouse_callback);
    glfwSetScrollCallback(window, scroll_callback);

    // tell GLFW to capture our mouse
    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);

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

    return window;
}