Main.cpp

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

#include <glad/glad.h>
#include <glad/glad.c>
//#include <glad/gl.h>
//#include <glad/gl.c>
#include <GLFW/glfw3.h>
#include "stb_image.h"

#include <iostream>
using namespace std;

#include "Shader.h"

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);

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

// stores how much we're seeing of either texture
float mixValue = 0.2f;

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    if(!glfwInit())
    {
        cout << "Failed to Init GLFW" << endl;
        exit(EXIT_FAILURE);
        //return -1;
    }
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
    
    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT,
        "LearnOpenGL", NULL, NULL);
    if(window == NULL)
    {
        cout << "Failed to create GLFW window" << endl;
        glfwTerminate();
        exit(EXIT_FAILURE);
        //return -1;
    }
    glfwMakeContextCurrent(window);    
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

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

    
    
    // build and compile our shader program
    // ------------------------------------
    Shader ourShader("3.3.shader.vs", "3.3.shader.fs");

    // set up vertex data (and buffer(s)) and configure vertex attributes
    // ------------------------------------------------------------------
    float vertices[] = {
        // positions          // colors           // texture coords
         0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
         0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
        -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
        -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left 
    };
    unsigned int indices[] = {
        0, 1, 3, // first triangle
        1, 2, 3  // second triangle
    };

    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(vertices), vertices, GL_STATIC_DRAW);

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

    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*) 0);
    glEnableVertexAttribArray(0);
    // color attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*) (3 * sizeof(float)));
    glEnableVertexAttribArray(1);
    // texture coord attribute
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*) (6 * sizeof(float)));
    glEnableVertexAttribArray(2);

    // load and create a texture 
    // -------------------------
    unsigned int texture1, texture2;
    glGenTextures(1, &texture1);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture1); // all upcoming GL_TEXTURE_2D operations now have effect on this texture object

    // set the texture wrapping parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	// set texture wrapping to GL_REPEAT (default wrapping method)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    // set texture filtering parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    // load image, create texture and generate mipmaps
    int width, height, nrChannels;
    stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.
    // The FileSystem::getPath(...) is part of the GitHub repository so we can find files on any IDE/platform; replace it with your own image path.
    unsigned char* data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
    if(data)
    {
        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);

    // texture 2
    // ---------
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);
    // set the texture wrapping parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	// set texture wrapping to GL_REPEAT (default wrapping method)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    // set texture filtering parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.
    // load image, create texture and generate mipmaps
    data = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0);
    if(data)
    {
        // note that the awesomeface.png has transparency and thus an alpha channel, so make sure to tell OpenGL the data type is of GL_RGBA
        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);

    // tell opengl for each sampler to which texture unit it belongs to (only has to be done once)
    // -------------------------------------------------------------------------------------------
    ourShader.use(); // don't forget to activate/use the shader before setting uniforms!
    // either set it manually like so:
    glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0);
    // or set it via the texture class
    ourShader.setInt("texture2", 1);

    // uncomment this call to draw in wireframe polygons.
    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    int nrAttributes;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &nrAttributes);
    cout << "Maximum nr of vertex attributes supported: " << nrAttributes << endl;

    
    //ourShader.setFloat("horizontal_offset", 0.5f);


    // render loop
    // -----------
    while(!glfwWindowShouldClose(window))
    {
        // input
        // -----
        processInput(window);

        // render
        // rendering commands here
        // ------
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // bind textures on corresponding texture units
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);

        // set the texture mix value in the shader
        ourShader.setFloat("mixValue", mixValue);



        // render container
        ourShader.use();

        glm::mat4 trans = glm::mat4(1.0f);
        //trans = glm::scale(trans, glm::vec3(0.5f, 0.5f, 0.5f));
        //trans = glm::rotate(trans, (float) glfwGetTime(), glm::vec3(0.0f, 0.0f, 1.0f));
        trans = glm::translate(trans, glm::vec3(0.5f, -0.5f, 0.0f));
        trans = glm::scale(trans, glm::vec3(0.5f, 0.5f, 0.5f));
        //trans = glm::rotate(trans, glm::radians(90.0f), glm::vec3(0.0, 0.0, 1.0));
        trans = glm::rotate(trans, (float) glfwGetTime(), glm::vec3(0.0, 0.0, 1.0));
        //trans = glm::scale(trans, glm::vec3(0.5f, 0.5f, 0.5f));
        unsigned int transformLoc = glGetUniformLocation(ourShader.ID, "transform");
        glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(trans));

        

        glBindVertexArray(VAO);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        trans = glm::mat4(1.0f);
        trans = glm::translate(trans, glm::vec3(-0.5f, 0.5f, 0.0f));
        float scaleAmount = sin( (float)glfwGetTime() );
        trans = glm::scale(trans, glm::vec3(scaleAmount, scaleAmount, 0.5f));
        //trans = glm::rotate(trans, (float) glfwGetTime(), glm::vec3(0.0, 0.0, 1.0));
        glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(trans));
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        glm::mat4 model = glm::mat4(1.0f);
        model = glm::rotate(model, glm::radians(-55.0f), glm::vec3(1.0f, 0.0f, 0.0f));
        int modelLoc = glGetUniformLocation(ourShader.ID, "model");
        glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));

        glm::mat4 view = glm::mat4(1.0f);
        // note that we're translating the scene in the reverse direction of where we want to move
        view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
        int viewLoc = glGetUniformLocation(ourShader.ID, "view");
        glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));

        glm::mat4 projection;
        projection = glm::perspective(glm::radians(45.0f), 800.0f / 600.0f, 0.1f, 100.0f);
        int projectionLoc = glGetUniformLocation(ourShader.ID, "projection");
        glUniformMatrix4fv(projectionLoc, 1, GL_FALSE, glm::value_ptr(projection));
        
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        /*glm::vec4 vec(1.0f, 0.0f, 0.0f, 1.0f);
        glm::mat4 trans = glm::mat4(1.0f);
        trans = glm::translate(trans, glm::vec3(1.0f, 1.0f, 0.0f));
        vec = trans * vec;
        std::cout << vec.x << vec.y << vec.z << std::endl;*/
        

        // 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);
    glDeleteBuffers(1, &EBO);
    //glDeleteProgram(shaderProgram);
    
    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwDestroyWindow(window);
    glfwTerminate();
    exit(EXIT_SUCCESS);
    //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_UP) == GLFW_PRESS)
    {
        mixValue += 0.001f; // change this value accordingly (might be too slow or too fast based on system hardware)
        if(mixValue >= 1.0f)
            mixValue = 1.0f;
    }
    if(glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS)
    {
        mixValue -= 0.001f; // change this value accordingly (might be too slow or too fast based on system hardware)
        if(mixValue <= 0.0f)
            mixValue = 0.0f;
    }
}

// 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);
}