第七個OpenGL程式,Camera 攝像機 (3d模型自轉)

雾枫發表於2024-04-09
效果:

程式碼main.cpp:

#include <iostream>
#include <glad/glad.h>
#include <glfw3.h>
#include "Shader.h"
#define STB_IMAGE_IMPLEMENTATION
#include <stb_image.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <chrono>
#include <thread>
using namespace std;

const unsigned int screenWidth = 800;
const unsigned int screenHeight = 600;

// 回撥函式,每當視窗改變大小,視口大小也跟隨改變
void framebuffer_size_callback(GLFWwindow* window,int width,int height)
{
    glViewport(0,0,width,height);
}

// 輸入 在GLFW中實現一些輸入控制
void processInput(GLFWwindow *window)
{
    if(glfwGetKey(window,GLFW_KEY_ESCAPE) == GLFW_PRESS)     // 是否按下了返回鍵(Esc)
    {
        glfwSetWindowShouldClose(window,true);               // 把WindowShouldClose屬性設定為 true來關閉GLFW
    }
}
// ************** opengl 具體實現 ************
    // 頂點資料
float vertices[] = {
    -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
    0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
    0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
    0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
    -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
    -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,

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

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

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

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

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

// glm::vec3陣列中定義10個立方體位置:
glm::vec3 cubePositions[] = {
    glm::vec3( 0.0f,  0.0f,  0.0f),
    glm::vec3( 2.0f,  5.0f, -15.0f),
    glm::vec3(-1.5f, -2.2f, -2.5f),
    glm::vec3(-3.8f, -2.0f, -12.3f),
    glm::vec3( 2.4f, -0.4f, -3.5f),
    glm::vec3(-1.7f,  3.0f, -7.5f),
    glm::vec3( 1.3f, -2.0f, -2.5f),
    glm::vec3( 1.5f,  2.0f, -2.5f),
    glm::vec3( 1.5f,  0.2f, -1.5f),
    glm::vec3(-1.3f,  1.0f, -1.5f)
};
//******************************************
int main()
{
    cout << "紋理" << endl;


// GLFW (視窗)
    glfwInit();                                                         // 初始化GLFW
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR,3);                       // 主版本號
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR,3);                       // 次版本號
    glfwWindowHint(GLFW_OPENGL_PROFILE,GLFW_OPENGL_CORE_PROFILE);       // 使用核心模式
    //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); Mac OS X系統

    // 建立一個GLFW視窗物件
    GLFWwindow* window = glfwCreateWindow(screenWidth ,screenHeight,"texture",NULL,NULL);
    if(window == NULL)
    {
        std::cout<< "Failed to create GLFW window"<<std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);                              // 視窗的上下文設定為當前執行緒的主上下文

// GLAD
    if(!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))      // 初始化GLAD(初始化OpenGL函式指標)
    {
        std::cout<<"Failed to initialize GLAD"<<std::endl;
        return -1;
    }

//*********** opengl 具體實現 ******************
    // 著色器類
    Shader shader("E:\\Project\\openglstudy2\\07_OpenglCamera\\07_OpenglCamera\\vertexSourceCode.vert",
                  "E:\\Project\\openglstudy2\\07_OpenglCamera\\07_OpenglCamera\\fragmentSourceCode.frag");

    // 頂點陣列物件 VAO
    unsigned int VAO;
    glGenVertexArrays(1,&VAO);   // 建立頂點陣列物件
    glBindVertexArray(VAO);      // 繫結頂點陣列物件
    // 頂點緩衝物件 VBO
    unsigned int VBO;
    glGenBuffers(1,&VBO);
    glBindBuffer(GL_ARRAY_BUFFER,VBO);                                       // 繫結頂點緩衝物件
    glBufferData(GL_ARRAY_BUFFER,sizeof(vertices),vertices,GL_STATIC_DRAW);  // 把之前定義的頂點資料複製到緩衝的記憶體中

    // 連結頂點屬性 (告訴 gpu 如何解析記憶體中的頂點資料)
    // 0 位置座標
    glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,5 * sizeof(float),(void*)0);
    glEnableVertexAttribArray(0);
    // 1 紋理座標
    glVertexAttribPointer(1,2,GL_FLOAT,GL_FALSE,5 * sizeof(float),(void*)(3*sizeof(float)));
    glEnableVertexAttribArray(1);

    unsigned int texture1,texture2;
    // 紋理物件1 texture1
    glGenTextures(1,&texture1);
    glBindTexture(GL_TEXTURE_2D,texture1);

    // 設定紋理影像環繞方式
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    // 設定紋理過濾
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    // 載入圖片
    int width,height,nrChannels;
    unsigned char *data = stbi_load("E:\\Project\\openglstudy2\\resources\\textures\\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;
    }
    // 釋放掉影像資料
    stbi_image_free(data);

    shader.use();
    // 紋理物件2 texture2
    glGenTextures(1,&texture2);
    glBindTexture(GL_TEXTURE_2D,texture2);

    // 設定紋理影像環繞方式
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);    // 重複
    // 設定紋理過濾
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    // 載入圖片
    stbi_set_flip_vertically_on_load(true);
    data = stbi_load("E:\\Project\\openglstudy2\\resources\\textures\\awesomeface.png",
                                    &width,&height,&nrChannels,0);
    if(data)
    {
        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;
    }
    // 釋放掉影像資料
    stbi_image_free(data);

    // 設定取樣器對應的紋理單元(unform)
    shader.use();
    shader.setInt("texture1",0);
    shader.setInt("texture2",1);

    // 啟用深度測試
    glEnable(GL_DEPTH_TEST);

    // 透視矩陣
    glm::mat4 projection = glm::perspective(glm::radians(45.0f), (float)screenWidth / (float)screenHeight, 0.1f, 100.0f);
    shader.setMat4("projection", projection);

//**************************




// 視口
    glViewport(0,0,screenWidth ,screenHeight);

// 視口跟隨視窗大小改變
    glfwSetFramebufferSizeCallback(window,framebuffer_size_callback);

// 渲染迴圈
    while(!glfwWindowShouldClose(window))                            // 檢查GLFW是否被要求退出
    {
        // 輸入 (使用者)
        processInput(window);                                        // 輸入控制(自定義)

        //************** 渲染指令 (使用者)**********

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

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);

        shader.use();
        // 建立轉換
        glm::mat4 view = glm::mat4(1.0f);
        float radius = 35.0f;  // 旋轉半徑
        float camX = static_cast<float>(sin(glfwGetTime()) * radius);
        float camZ = static_cast<float>(cos(glfwGetTime()) * radius);
        view = glm::lookAt(glm::vec3(camX, 0.0f, camZ), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
        shader.setMat4("view", view);

        //
        glBindVertexArray(VAO);
        for (unsigned int i = 0; i < 10; i++)
        {
            // 計算每個物件的模型矩陣,並在繪製前將其傳遞給shader
            glm::mat4 model = glm::mat4(1.0f);
            model = glm::translate(model, cubePositions[i]);
            float angle = 20.0f * i;
            model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));
            shader.setMat4("model", model);

            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        //***************************************

        // 檢查並呼叫事件,交換緩衝 (預設操作)
        glfwSwapBuffers(window);                                     // 交換顏色緩衝(它是一個儲存著GLFW視窗每一個畫素顏色值的大緩衝),它在這一迭代中被用來繪製,並且將會作為輸出顯示在螢幕上。
        glfwPollEvents();                                            // 有沒有觸發什麼事件(比如鍵盤輸入、滑鼠移動等)、更新視窗狀態
    }

    // 解綁 VAO  VBO 著色器程式物件
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);


// 當渲染迴圈結束後我們需要正確釋放/刪除之前的分配的所有資源
    glfwTerminate();
    return 0;
}

著色器程式碼:

頂點著色器:

#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoord;

out vec2 TexCoord;

uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;

void main()
{
        gl_Position = projection * view * model * vec4(aPos, 1.0f);
        TexCoord = vec2(aTexCoord.x, aTexCoord.y);
}

片段著色器:

#version 330 core
out vec4 FragColor;

in vec3 ourColor;
in vec2 TexCoord;

// 定義一個全域性的2D紋理取樣器
uniform sampler2D texture1;
uniform sampler2D texture2;
void main()
{
    // GLSL內建的mix函式需要接受兩個值作為引數,並對它們根據第三個引數進行線性插值。
  FragColor = mix(texture(texture1, TexCoord), texture(texture2, vec2(-TexCoord.x,TexCoord.y)), 0.2);
}

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