advCubeDemo.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 <vector>

const char* vertexShaderSource = R"glsl(
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;

uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
uniform vec3 lightPos;
uniform vec3 viewPos;

out vec3 FragPos;
out vec3 Normal;
out vec3 LightPos;
out vec3 ViewPos;

void main()
{
    FragPos = vec3(model * vec4(aPos, 1.0));
    Normal = mat3(transpose(inverse(model))) * aNormal;
    LightPos = lightPos;
    ViewPos = viewPos;
    gl_Position = projection * view * vec4(FragPos, 1.0);
}
)glsl";

const char* fragmentShaderSource = R"glsl(
#version 330 core
out vec4 FragColor;

in vec3 FragPos;
in vec3 Normal;
in vec3 LightPos;
in vec3 ViewPos;

void main()
{
    // Ambient light
    float ambientStrength = 0.5;
    vec3 ambient = ambientStrength * vec3(1.0, 0.65, 0.0); // Orange color

    // Diffuse light
    vec3 norm = normalize(Normal);
    vec3 lightDir = normalize(LightPos - FragPos);
    float diff = max(dot(norm, lightDir), 0.0);
    vec3 diffuse = diff * vec3(1.0, 0.65, 0.0); // Orange color

    vec3 result = (ambient + diffuse);
    FragColor = vec4(result, 1.0);
}
)glsl";

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

// Camera
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 yaw   = -90.0f;
float pitch = 0.0f;
float fov = 45.0f;

// Timing
float deltaTime = 0.0f;
float lastFrame = 0.0f;

void processInput(GLFWwindow *window) {
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);

    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;
    if (glfwGetKey(window, GLFW_KEY_SPACE) == GLFW_PRESS)
        cameraPos += cameraSpeed * cameraUp;
    if (glfwGetKey(window, GLFW_KEY_LEFT_SHIFT) == GLFW_PRESS)
        cameraPos -= cameraSpeed * cameraUp;
}

std::vector<float> vertices = {
    // positions         // normals
    -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
     0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
     0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
     0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    -0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,

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

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

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

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

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

int main() {
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "OpenGL Cube Demo", NULL, NULL);
    if (window == NULL) {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    unsigned int VBO, VAO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(float), &vertices[0], GL_STATIC_DRAW);

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

    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);
    int success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
    }

    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    }

    unsigned int shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }
    //glDeleteShader(vertexShader);
    //glDeleteShader(fragmentShader);
    glValidateProgram(shaderProgram);
    glGetProgramiv(shaderProgram, GL_VALIDATE_STATUS, &success);
    if(success == GL_FALSE)
    {
        GLchar errorLog[1024] = {0};
        glGetProgramInfoLog(shaderProgram, 1024, NULL, errorLog);
        std::cout << "error validating shader program; Details: " << errorLog << std::endl;;
        return NULL;
    }


    glEnable(GL_DEPTH_TEST);

    glm::vec3 lightPos(1.2f, 1.0f, 2.0f);

    while (!glfwWindowShouldClose(window)) {
        float currentFrame = glfwGetTime();
        deltaTime = currentFrame - lastFrame;
        lastFrame = currentFrame;

        processInput(window);

        glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glUseProgram(shaderProgram);
        glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "projection"), 1, GL_FALSE, glm::value_ptr( glm::perspective(glm::radians(fov), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 120.0f)));
        glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "view"), 1, GL_FALSE, glm::value_ptr(glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp)));

        // This code rotates the object so we can better see how the lighting works
        float distance = -2.0f; 
        glm::vec3 translationVector(0.0f, 0.0f, distance);

        glm::mat4 rotationX = glm::rotate(glm::mat4(1.0f), glm::radians(45.0f), glm::vec3(1.0f, 0.0f, 0.0f));
        glm::mat4 rotationY = glm::rotate(glm::mat4(1.0f), glm::radians(45.0f), glm::vec3(0.0f, 1.0f, 0.0f));
        glm::mat4 rotationZ = glm::rotate(glm::mat4(1.0f), glm::radians(45.0f), glm::vec3(0.0f, 0.0f, 1.0f));

        glm::mat4 model = glm::translate(glm::mat4(1.0f), translationVector) * rotationX * rotationY;

        // Replace the code above with this to set the cube to face front again
        //glm::mat4 model = glm::mat4(1.0f);

        glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "model"), 1, GL_FALSE, glm::value_ptr(model));

        glUniform3fv(glGetUniformLocation(shaderProgram, "lightPos"), 1, &lightPos[0]);
        glUniform3fv(glGetUniformLocation(shaderProgram, "viewPos"), 1, &cameraPos[0]);

        glBindBuffer(GL_ARRAY_BUFFER, VBO);
        glDrawArrays(GL_TRIANGLES, 0, 36);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);

    glfwTerminate();
    return 0;
}