modelload.cpp

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

#include "Shader.h"
#include "Camera.h"
#include "stb_image.h"

#include<iostream>
#include<algorithm>
#include<cstdint>


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


#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void move_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xpos, double ypos);
void processInput(GLFWwindow* window);
void updateDelta();
unsigned int loadTexture(const char* path);
float clamp(float up, float down, float val);

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

float lastX = SCR_WIDTH / 2;
float lastY = SCR_HEIGHT / 2;

float deltaTime = 0.0f;
float lastFrame = 0.0f;
bool firstMouse = true;

Camera camera(glm::vec3(0.0f, 0.0f, 6.0f));

glm::vec3 LightPos(1.0f, 1.0f, 2.0f);

struct Vertex {
    glm::vec3 Position;
    glm::vec3 Normal;
    glm::vec2 TexCoords;
};

struct Texture {
    unsigned int id = 0;
    std::string type; // diffuse or specular
    std::string path;
};

class Mesh {
    public:
        std::vector<Vertex> vertices;
        std::vector<unsigned int> indices;
        std::vector<Texture> textures;
        Mesh(std::vector<Vertex> vertices, std::vector<unsigned int> indices, std::vector<Texture> textures) {
            this->vertices = vertices;
            this->indices = indices;
            this->textures = textures;
            setupMesh();
        }
        void Draw(Shader &shader) {
            unsigned int diffuseCount = 1;
            unsigned int specularCount = 1;
            for (unsigned int i = 0; i < textures.size(); i++) {
                glActiveTexture(GL_TEXTURE0 + i);  // activate texture unit i
                std::string number;
                std::string name = textures[i].type;
                if (name == "diffuse")
                    number = std::to_string(diffuseCount++);
                else if (name == "specular")
                    number = std::to_string(specularCount++);
                shader.setFloat("material." + name + number, (float)i);   // material.diffuse1, material.specular1, ...
                glBindTexture(GL_TEXTURE_2D, textures[i].id);
            }
            glActiveTexture(GL_TEXTURE0);

            // draw mesh
            glBindVertexArray(VAO);
            glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);
            glBindVertexArray(0);
        }
    private:
        unsigned int VAO, VBO, EBO;
        void setupMesh() {
            glGenVertexArrays(1, &VAO);
            glGenBuffers(1, &VBO);
            glGenBuffers(1, &EBO);

            glBindVertexArray(VAO);
            glBindBuffer(GL_ARRAY_BUFFER, VBO);
            glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex),
                &vertices[0], GL_STATIC_DRAW);
            glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
            glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() *
                sizeof(unsigned int), &indices[0], GL_STATIC_DRAW);
            // vertex positions
            glEnableVertexAttribArray(0);
            glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
                (void*)0);
            // vertex normals
            glEnableVertexAttribArray(1);
            glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
                (void*)offsetof(Vertex, Normal));
            // vertex texture coords
            glEnableVertexAttribArray(2);
            glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
                (void*)offsetof(Vertex, TexCoords));
            glBindVertexArray(0);
        }
};

class Model {
    public:
        Model(std::string path) {
            loadModel(path);
        }
        void Draw(Shader &shader) {
            for (unsigned int i = 0; i < meshes.size(); i++)
                meshes[i].Draw(shader);
        }
    private:    
        std::vector<Mesh> meshes;
        std::string directory;
        std::vector<Texture> textures_loaded;
        void loadModel(std::string path) {
            Assimp::Importer importer;
            const aiScene* scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);
            if (!scene || scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE ||
                !scene->mRootNode)
            {
                std::cout << "ERROR::ASSIMP::" << importer.GetErrorString() << std::endl;
                return;
            }
            directory = path.substr(0, path.find_last_of('/'));
            processNode(scene->mRootNode, scene);
        }
        void processNode(aiNode* node, const aiScene* scene) {
            for (unsigned int i = 0; i < node->mNumMeshes; i++) {
                aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
                meshes.push_back(processMesh(mesh, scene));
            }
            for (unsigned int i = 0; i < node->mNumChildren; i++) {
                processNode(node->mChildren[i], scene);
            }
        }
        Mesh processMesh(aiMesh* mesh, const aiScene* scene) {
            std::vector<Vertex> vertices;
            std::vector<unsigned int> indices;
            std::vector<Texture> textures;
            for (unsigned int i = 0; i < mesh->mNumVertices; i++) {
                Vertex vertex;
                vertex.Position = glm::vec3(mesh->mVertices[i].x, mesh->mVertices[i].y, mesh->mVertices[i].z);
                vertex.Normal = glm::vec3(mesh->mNormals[i].x, mesh->mNormals[i].y, mesh->mNormals[i].z);
                if (mesh->mTextureCoords[0]) {
                    vertex.TexCoords = glm::vec2(mesh->mTextureCoords[0][i].x, mesh->mTextureCoords[0][i].y);
                }
                else {
                    vertex.TexCoords = glm::vec2(0.0f, 0.0f);
                }
                vertices.push_back(vertex);
            }
            for (unsigned int i = 0; i < mesh->mNumFaces; i++) {
                aiFace face = mesh->mFaces[i];
                for (unsigned int j = 0; j < face.mNumIndices; j++) {
                    indices.push_back(face.mIndices[j]);
                }
            }
            if (mesh->mMaterialIndex >= 0) {
                aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];
                std::vector<Texture> diffuse = loadMaterialTextures(material, aiTextureType_DIFFUSE, "diffuse");
                textures.insert(textures.end(), diffuse.begin(), diffuse.end());
                std::vector<Texture> specular = loadMaterialTextures(material, aiTextureType_SPECULAR, "specular");
                textures.insert(textures.end(), specular.begin(), specular.end());
            }

            return Mesh(vertices, indices, textures);
        }
        std::vector<Texture> loadMaterialTextures(aiMaterial* mat, aiTextureType type, std::string typeName) {
            std::vector<Texture> textures;
            for (unsigned int i = 0; i < mat->GetTextureCount(type); i++) {
                bool skip = false;
                aiString str;  // texture filename
                mat->GetTexture(type, i, &str);
                const char* path = str.C_Str();
                std::string filename = std::string(path);
                for (unsigned int j = 0; j < textures_loaded.size(); j++) {
                    if (std::strcmp(textures_loaded[j].path.data(), path) == 0) {
                        textures.push_back(textures_loaded[j]);
                        skip = true;
                        break;
                    }
                }
                if (!skip) {
                    filename = directory + '/' + filename;
                    Texture texture;
                    texture.id = loadTexture(filename.c_str());
                    texture.type = typeName;
                    texture.path = std::string(path);
                    textures.push_back(texture);
                    textures_loaded.push_back(texture);
                }
            }
            return textures;
        }
};


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);
    glfwSetCursorPosCallback(window, move_callback);
    glfwSetScrollCallback(window, scroll_callback);
    // 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 -1;
    }

    Shader lightShader("basic_lighting_shader_light.vert", "basic_lighting_shader_light.frag");

    // set up vertex data (and buffer(s)) and configure vertex attributes
    // ------------------------------------------------------------------
    float vertices[] = {
        // position              normal vector            texture coordinates
        -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  0.0f,
         0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  0.0f,
         0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  1.0f,
         0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  1.0f,
        -0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  1.0f,
        -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  0.0f,

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

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

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

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

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

    unsigned int VBO, VAO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    unsigned stride = 8 * sizeof(float);
    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0);
    glEnableVertexAttribArray(0);
    // normal vector attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, stride, (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);
    // texture coordinate attibute
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, stride, (void*)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);

    unsigned int lightVAO;
    glGenVertexArrays(1, &lightVAO);
    glBindVertexArray(lightVAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0);
    glEnableVertexAttribArray(0);


    glEnable(GL_DEPTH_TEST);

    Model backpack("./carrot/carrot.obj");
    Shader backpackShader("modelloading.vert", "modelloading.frag");

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

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

        glBindVertexArray(VAO);
        // LookAt: position, target, up vector

        glm::vec3 lightPos = glm::vec3(LightPos.x * glm::sin(glfwGetTime()), LightPos.y * glm::cos(glfwGetTime()), LightPos.z);



        glm::mat4 view = camera.GetViewMatrix();
        glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / SCR_HEIGHT, 0.1f, 100.0f);

        // render cube object under light
        glBindVertexArray(VAO);


        // render lamp object
        lightShader.use();
        lightShader.setMat4("view", view);
        lightShader.setMat4("projection", projection);
        glm::mat4 model = glm::mat4(1.0f);
        model = glm::translate(model, lightPos);
        model = glm::scale(model, glm::vec3(0.2f));
        lightShader.setMat4("model", model);
        glBindVertexArray(lightVAO);
        glDrawArrays(GL_TRIANGLES, 0, sizeof(vertices) / stride);

        // render backpack 3d
        backpackShader.use();
        backpackShader.setVec3("light.ambient", 0.2f, 0.2f, 0.2f);
        backpackShader.setVec3("light.diffuse", 0.5f, 0.5f, 0.5f);
        backpackShader.setVec3("light.specular", 1.0f, 1.0f, 1.0f);
        backpackShader.setVec3("light.position", lightPos);
        backpackShader.setFloat("light.constant", 1.0f);
        backpackShader.setFloat("light.linear", 0.09f);
        backpackShader.setFloat("light.quadratic", 0.032f);
        backpackShader.setVec3("viewPos", camera.Position);

        model = glm::mat4(1.0f);
        model = glm::translate(model, glm::vec3(0.0f, 0.0f, 0.0f)); // translate it down so it's at the center of the scene
        model = glm::scale(model, glm::vec3(1.0f, 1.0f, 1.0f));	// it's a bit too big for our scene, so scale it down
        backpackShader.setMat4("view", view);
        backpackShader.setMat4("projection", projection);
        backpackShader.setMat4("model", model);
        backpack.Draw(backpackShader);



        // 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);
    glDeleteVertexArrays(1, &lightVAO);
    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);
    if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
        camera.ProcessKeyboard(Camera_Movement::FORWARD, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
        camera.ProcessKeyboard(Camera_Movement::BACKWARD, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
        camera.ProcessKeyboard(Camera_Movement::LEFT, deltaTime);
    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
        camera.ProcessKeyboard(Camera_Movement::RIGHT, deltaTime);
}

// 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)
{
    glViewport(0, 0, width, height);
}

float clamp(float up, float down, float val) {
    if (val > up) return up;
    if (val < down) return down;
    return val;
}

void updateDelta() {
    float time = glfwGetTime();
    deltaTime = time - lastFrame;
    lastFrame = time;
}

void move_callback(GLFWwindow* window, double xpos, double ypos) {
    if (firstMouse) {
        lastX = xpos;
        lastY = ypos;
        firstMouse = false;
    }
    if (glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) == GLFW_RELEASE) {
        firstMouse = true;
        return;
    }
    float xoffset = xpos - lastX;
    float yoffset = ypos - lastY;
    lastX = xpos;
    lastY = ypos;

    camera.ProcessMouseMovement(xoffset, yoffset);

}

void scroll_callback(GLFWwindow* window, double xpos, double ypos) {
    camera.ProcessMouseScroll(static_cast<float>(ypos));
}

unsigned int loadTexture(const char* path) {
    // initialize texture object
    unsigned int textureId;
    glGenTextures(1, &textureId);
    glBindTexture(GL_TEXTURE_2D, textureId);     // all upcoming GL_TEXTURE_2D operations have effect on this object
    // texture wrapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    // texture filtering
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    int width, height, nrChannels;
    unsigned char* data = stbi_load(path, &width, &height, &nrChannels, 0);

    GLenum format = GL_RGBA;
    if (nrChannels == 1)
        format = GL_RED;
    else if (nrChannels == 3)
        format = GL_RGB;
    else if (nrChannels == 4)
        format = GL_RGBA;

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