main.cpp

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


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

#include "src/scene.h"
#include "utils/constants.h"

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);
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods);
void debug_message_callback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const void *userParam);

// camera
Camera camera(glm::vec3(0.0f, 8.0f, 15.0f), glm::vec3(0.0f, 1.0f, 0.0f), /* yaw */ -90.0, /* pitch */ -25.0);
double lastX = Constants::SCR_WIDTH / 2.0f;
double lastY = Constants::SCR_HEIGHT / 2.0f;
bool firstMouse = true;

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

// Options
bool debug = true;

glm::vec3 lightPosition(10.0, 50.0, 10.0);

std::unique_ptr<Scene> underwater_scene;

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, debug ? GL_TRUE : GL_FALSE);

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

    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(Constants::SCR_WIDTH, Constants::SCR_HEIGHT, "Underwater Watercolor", NULL, NULL);
    glfwSetWindowPos(window, Constants::SCR_WIDTH / 2, 50);

    if (window == NULL)
    {
        spdlog::critical("Failed to create GLFW window");
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    glfwSetCursorPosCallback(window, mouse_callback);
    glfwSetScrollCallback(window, scroll_callback);

    // tell GLFW to capture our mouse
    #ifdef _WIN32
        glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
    #endif
    glfwSetKeyCallback(window, key_callback);

    // glad: load all OpenGL function pointers
    // ---------------------------------------
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        spdlog::critical("Failed to initialize GLAD");
        return -1;
    }
    spdlog::info("Using Opengl {}.{}", GLVersion.major, GLVersion.minor);
    stbi_set_flip_vertically_on_load(true);

    // configure global opengl state
    // -----------------------------
    glEnable(GL_DEPTH_TEST);
    underwater_scene = make_unique<Scene>();

    // render loop
    // -----------
    while (!glfwWindowShouldClose(window))
    {
        // per-frame time logic
        // --------------------
        double currentFrame = glfwGetTime();
        deltaTime = currentFrame - lastFrame;
        lastFrame = currentFrame;

        // input
        // -----
        processInput(window);
        underwater_scene->render(&camera, currentFrame);
        
        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // 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 || glfwGetKey(window, GLFW_KEY_Z) == GLFW_PRESS) {
        glfwSetWindowShouldClose(window, true);
    }
    // Movement inputs - continuous
    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_E) == GLFW_PRESS)
        camera.ProcessKeyboard(UP, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS)
        camera.ProcessKeyboard(DOWN, deltaTime);
}

void key_callback(GLFWwindow* /*window*/, int key, int, int action, int)
{
    if (underwater_scene && action == GLFW_PRESS) {
        underwater_scene->processInputs(key);
    }
}

// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow*, 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*, double xpos, double ypos)
{
    if (firstMouse)
    {
        lastX = xpos;
        lastY = ypos;
        firstMouse = false;
    }

    double xoffset = xpos - lastX;
    double 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*, double, double yoffset)
{
    camera.ProcessMouseScroll(yoffset);
}

void debug_message_callback(
        GLenum,
        GLenum,
        GLuint,
        GLenum severity,
        GLsizei gl_message_length,
        const GLchar *gl_message,
        const void *) {

    spdlog::level::level_enum level;
    switch (severity) {
        case GL_DEBUG_SEVERITY_NOTIFICATION:
            level = spdlog::level::debug;
            break;
        case GL_DEBUG_SEVERITY_LOW:
            level = spdlog::level::info;
            break;
        case GL_DEBUG_SEVERITY_MEDIUM:
            level = spdlog::level::warn;
            break;
        case GL_DEBUG_SEVERITY_HIGH:
            level = spdlog::level::err;
            break;
        default:
            level = spdlog::level::err;
    }

    std::string message;
    if (gl_message_length < 0) {
        message = std::string(gl_message);
    }
    else {
        message = std::string(gl_message, gl_message_length);
    }

    spdlog::log(level, message);
}