OpenGL基礎25：多光源（附簡單GLSL配置）

原創 Jaihk662 2020-06-24 08:32

 

到這裏，光照基礎就已經接近尾聲了，當然對於光照渲染的學習，這可能只是百步中的一步，儘管如此，至少還是做到了從 0 到 1 的一個過程，就像之前剛學會“HelloWorld”一樣，一切偉大的行動和思想，都有一個微不足道的開始

再次聲明：直至這一章，主要還是參考於 https://learnopengl.com/，當然這不僅是翻譯，也結合了不少其它的文獻和教學視頻，和原文略有不同，很多地方去掉了繁雜或不重要的描述，加入了自己的看法，整體更加整潔易懂

  • 如有問題/錯誤，求反饋

一、GLSL配置

之前着色器用的一直都是.txt，專不專業不重要，重要的是沒有高亮。。

一樣，以VS2019爲例，工具 → 擴展，如下，下載GLSL：

成功之後，要將所有的頂點着色器改成.vert後綴、所有的片段着色器改成.frag後綴，搞定！

 

二、多光源測試

嘗試把 OpenGL基礎24：聚光燈 和 OpenGL基礎23：平行光與點光源 都加到場景中

一般來講，光源可能不止一個，例如下面舉例的場景，就有5個光源，其中3個點光源，太陽光和聚光燈各1個

之前片段着色器的寫法有點僵硬，面對這麼多光源，貌似代碼不是特別好改，總不可能每個光源都寫一遍一樣的邏輯吧，所以需要優化一下片段着色器的結構

先拿最簡單的平行光作爲例子，定義的方式不變，可以寫一個函數來輸出平行光對當前片段的顏色貢獻：

vec3 CalcSunLight(SunLight light, vec3 normal, vec3 viewDir)
{
    vec3 lightDir = normalize(-light.direction);
    float diff = max(dot(normal, lightDir), 0.0f);
    vec3 diffuse = light.diffuse * (diff * vec3(texture(material.diffuse, texIn)));

    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * (spec * vec3(texture(material.specular, texIn)));

    return diffuse + specular;
}

這樣就可以類比推出點光照和聚光燈的函數，對於需要傳入的參數而言，平行光只需要光的屬性、法向量和視角向量，但是對於後面兩者，還需要片段的位置，不然無法得到光照的入射方向

搞定之後，片段着色器主函數就可以寫的非常整潔了：

這樣的話，相當於每個光源都是獨立計算的

void main()
{
    //環境光
    vec3 ambient = ambient * vec3(texture(material.diffuse, texIn));
    vec3 viewDir = normalize(viewPos - fragPosIn);
    vec3 normal = normalize(normalIn);
    vec3 result = CalcSunLight(sunLight, normal, viewDir);
    for (int i = 0; i <= 2; i++)
        result = result + CalcPointLight(pointLights[i], normal, fragPosIn, viewDir);
    result = result + CalcSpotLight(spotLight, normal, fragPosIn, viewDir);
    color = vec4(result, 1.0f);
}

看下效果：

完整代碼：

#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texture;
out vec2 texIn;
out vec3 normalIn;
out vec3 fragPosIn;
uniform mat4 model;             //模型矩陣
uniform mat4 view;              //觀察矩陣
uniform mat4 projection;        //投影矩陣
void main()
{
    gl_Position = projection * view * model * vec4(position, 1.0);
    texIn = vec2(texture.x, 1.0f - texture.y);
    fragPosIn = vec3(model * vec4(position, 1.0f));
    normalIn = mat3(transpose(inverse(model))) * normal;
}

/////////////////////////////////////////////////////////////////////

#version 330 core
struct Material
{
    sampler2D diffuse;      //貼圖
    sampler2D specular;     //鏡面貼圖
    sampler2D emission;     //放射貼圖
    float shininess;        //反光度
};
struct SunLight             //平行光
{
    vec3 direction;
    vec3 diffuse;
    vec3 specular;
};
struct PointLight           //點光源
{
    vec3 position;
    vec3 diffuse;
    vec3 specular;
    float k0, k1, k2;
};
struct SpotLight            //聚光燈
{
    vec3 position;
    vec3 direction;
    vec3 diffuse;
    vec3 specular;
    float k0, k1, k2;
    float cutOff, outCutOff;
};
uniform vec3 ambient;
uniform Material material;
uniform SunLight sunLight;
uniform PointLight pointLights[3];
uniform SpotLight spotLight;
vec3 CalcSunLight(SunLight light, vec3 normal, vec3 viewDir);
vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
vec3 CalcSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
out vec4 color;
uniform vec3 viewPos;
in vec2 texIn;
in vec3 fragPosIn;
in vec3 normalIn;
void main()
{
    //環境光
    vec3 ambient = ambient * vec3(texture(material.diffuse, texIn));
    vec3 viewDir = normalize(viewPos - fragPosIn);
    vec3 normal = normalize(normalIn);
    vec3 result = CalcSunLight(sunLight, normal, viewDir);
    for (int i = 0; i <= 2; i++)
        result = result + CalcPointLight(pointLights[i], normal, fragPosIn, viewDir);
    result = result + CalcSpotLight(spotLight, normal, fragPosIn, viewDir);
    color = vec4(result, 1.0f);
}

vec3 CalcSunLight(SunLight light, vec3 normal, vec3 viewDir)
{
    vec3 lightDir = normalize(-light.direction);
    float diff = max(dot(normal, lightDir), 0.0f);
    vec3 diffuse = light.diffuse * (diff * vec3(texture(material.diffuse, texIn)));

    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * (spec * vec3(texture(material.specular, texIn)));

    return diffuse + specular;
}

vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
    vec3 lightDir = normalize(light.position - fragPos);
    float diff = max(dot(normal, lightDir), 0.0f);
    vec3 diffuse = light.diffuse * (diff * vec3(texture(material.diffuse, texIn)));

    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * (spec * vec3(texture(material.specular, texIn)));

    float dis = length(light.position - fragPos);
    float attenuation = 1.0f / (light.k0 + light.k1 * dis + light.k2 * (dis * dis));

    diffuse *= attenuation;
    specular *= attenuation;
    return diffuse + specular;
}

vec3 CalcSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
    vec3 lightDir = normalize(light.position - fragPos);
    float theta = dot(lightDir, normalize(-light.direction));
    float lightSoft = clamp((theta - light.outCutOff) / (light.cutOff - light.outCutOff), 0.0f, 1.0f);

    float diff = max(dot(normal, lightDir), 0.0f);
    vec3 diffuse = light.diffuse * (diff * vec3(texture(material.diffuse, texIn)));

    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * (spec * vec3(texture(material.specular, texIn)));

    float dis = length(light.position - fragPos);
    float attenuation = 1.0f / (light.k0 + light.k1 * dis + light.k2 * (dis * dis));

    diffuse *= attenuation * lightSoft;
    specular *= attenuation * lightSoft;
    return diffuse + specular;
}

main.cpp：

#include<iostream>
#include<opengl/glew.h>
#define GLEW_STATIC
#include<GLFW/glfw3.h>
#include"Camera.h"
#include<glm/glm.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<glm/gtc/type_ptr.hpp>
#include"Shader.h"
#include<opengl/freeglut.h>
#include<SOIL.h>

bool keys[1024];
Camera camera;
GLfloat lastX, lastY;
bool firstMouse = true;
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void cameraMove();
const GLuint WIDTH = 800, HEIGHT = 600;

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

    GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
    glfwMakeContextCurrent(window);
    glfwSetKeyCallback(window, key_callback);
    glfwSetCursorPosCallback(window, mouse_callback);
    glfwSetScrollCallback(window, scroll_callback);

    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
    glewExperimental = GL_TRUE;
    glewInit();

    int width, height;
    glfwGetFramebufferSize(window, &width, &height);
    glViewport(0, 0, width, height);

    Shader shaderObj("ObjVShader.vert", "ObjFShader.frag");
    Shader shaderLight("LightVShader.vert", "LightFShader.frag");

    GLfloat vertices[] = 
    {
        -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
    };
    glm::vec3 positions[] = 
    {
        glm::vec3(0.0f, -2.0f, 0.0f),
        glm::vec3(0.0f, -1.0f, 0.0f),
        glm::vec3(0.0f, 0.0f, 0.0f),
        glm::vec3(-2.0f, -2.0f, 0.0f),
        glm::vec3(-2.0f, -1.0f, 0.0f),
        glm::vec3(-3.0f, -2.0f, 0.0f),
        glm::vec3(-2.0f, -2.0f, 1.0f),
        glm::vec3(-1.0f, -2.0f, -4.0f),
    };
    glm::vec3 pointLightPositions[] = 
    {
       glm::vec3(-1.0f, 0.0f, -2.0f),
       glm::vec3(0.0f, -1.0f, 2.0f),
       glm::vec3(-5.0f, -1.0f, 1.0f),
    };
    GLuint VBO, VAO, textureA, textureB;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);

    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
    glEnableVertexAttribArray(2);

    int picWidth, picHeight;
    glGenTextures(1, &textureA);
    glBindTexture(GL_TEXTURE_2D, textureA);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    unsigned char* image = SOIL_load_image("Texture/wood2.jpg", &picWidth, &picHeight, 0, SOIL_LOAD_RGB);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, picWidth, picHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
    glGenerateMipmap(GL_TEXTURE_2D);
    SOIL_free_image_data(image);

    glGenTextures(1, &textureB);
    glBindTexture(GL_TEXTURE_2D, textureB);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST_MIPMAP_NEAREST);
    image = SOIL_load_image("Texture/specular.jpg", &picWidth, &picHeight, 0, SOIL_LOAD_RGB);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, picWidth, picHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
    glGenerateMipmap(GL_TEXTURE_2D);
    SOIL_free_image_data(image);
    glBindTexture(GL_TEXTURE_2D, 0);

    shaderObj.Use();
    glUniform1i(glGetUniformLocation(shaderObj.Program, "material.diffuse"), 0);
    glUniform1i(glGetUniformLocation(shaderObj.Program, "material.specular"), 1);

    GLuint lightVAO;
    glGenVertexArrays(1, &lightVAO);
    glBindVertexArray(lightVAO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
    //VBO數據已經綁定且我們就用之前的頂點數據，所以無需再管理VBO
    glEnableVertexAttribArray(0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    glEnable(GL_DEPTH_TEST);
    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        glClear(GL_DEPTH_BUFFER_BIT);
        cameraMove();

        shaderLight.Use();
        glm::mat4 view = camera.GetViewMatrix();
        glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (GLfloat)WIDTH / (GLfloat)HEIGHT, 0.1f, 100.0f);
        glm::mat4 model = glm::mat4(1.0f);
        GLint modelLoc = glGetUniformLocation(shaderLight.Program, "model");
        GLint viewLoc = glGetUniformLocation(shaderLight.Program, "view");
        GLint projLoc = glGetUniformLocation(shaderLight.Program, "projection");
        glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
        glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));

        glBindVertexArray(lightVAO);
        for (int i = 0; i <= 2; i++)
        {
            model = glm::translate(glm::mat4(1.0f), pointLightPositions[i]);
            model = glm::scale(model, glm::vec3(0.2f));
            glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        shaderObj.Use();
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, textureA);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, textureB);
        GLint matSpecularLoc = glGetUniformLocation(shaderObj.Program, "material.specular");
        GLint matShineLoc = glGetUniformLocation(shaderObj.Program, "material.shininess");
        glUniform3f(matSpecularLoc, 0.0f, 0.0f, 0.0f);
        glUniform1f(matShineLoc, 32.0f);

        glUniform3f(glGetUniformLocation(shaderObj.Program, "sunLight.direction"), -0.2f, -1.0f, -0.3f);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "sunLight.diffuse"), 0.4f, 0.4f, 0.4f);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "sunLight.specular"), 0.5f, 0.5f, 0.5f);

        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[0].position"), pointLightPositions[0].x, pointLightPositions[0].y, pointLightPositions[0].z);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[0].diffuse"), 0.8f, 0.8f, 0.8f);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[0].specular"), 1.0f, 1.0f, 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[0].k0"), 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[0].k1"), 0.09);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[0].k2"), 0.032);

        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[1].position"), pointLightPositions[1].x, pointLightPositions[1].y, pointLightPositions[1].z);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[1].diffuse"), 0.8f, 0.8f, 0.8f);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[1].specular"), 1.0f, 1.0f, 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[1].k0"), 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[1].k1"), 0.09);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[1].k2"), 0.032);

        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[2].position"), pointLightPositions[2].x, pointLightPositions[2].y, pointLightPositions[2].z);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[2].diffuse"), 0.8f, 0.8f, 0.8f);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[2].specular"), 1.0f, 1.0f, 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[2].k0"), 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[2].k1"), 0.09);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[2].k2"), 0.032);

        glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.position"), camera.Position.x, camera.Position.y, camera.Position.z);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.direction"), camera.Front.x, camera.Front.y, camera.Front.z);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.diffuse"), 1.0f, 1.0f, 1.0f);
        glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.specular"), 1.0f, 1.0f, 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.k0"), 1.0f);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.k1"), 0.09);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.k2"), 0.032);
        glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.cutOff"), glm::cos(glm::radians(12.5f)));
        glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.outCutOff"), glm::cos(glm::radians(16.0f)));

        GLint lightAmbientLoc = glGetUniformLocation(shaderObj.Program, "ambient");
        GLint viewPosLoc = glGetUniformLocation(shaderObj.Program, "viewPos");
        glUniform3f(lightAmbientLoc, 0.2f, 0.2f, 0.2f);
        glUniform3f(viewPosLoc, camera.Position.x, camera.Position.y, camera.Position.z);
        model = glm::mat4(1.0f);
        model = glm::rotate(model, glm::radians(57.0f), glm::vec3(-0.5f, 1.0f, 0.0f));
        modelLoc = glGetUniformLocation(shaderObj.Program, "model");
        viewLoc = glGetUniformLocation(shaderObj.Program, "view");
        projLoc = glGetUniformLocation(shaderObj.Program, "projection");
        glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
        glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));

        glBindVertexArray(VAO);
        for (int i = 0; i <= 7; i++)
        {
            model = glm::translate(glm::mat4(1.0f), positions[i]);
            model = glm::rotate(model, glm::radians(0.0f), glm::vec3(-0.5f, 1.0f, 0.0f));
            glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        glBindVertexArray(0);
        glfwSwapBuffers(window);
    }
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glfwTerminate();
    return 0;
}

GLfloat deltaTime = 0.0f;
GLfloat lastFrame = 0.0f;
void cameraMove()
{
    GLfloat currentFrame = glfwGetTime();
    deltaTime = currentFrame - lastFrame;
    lastFrame = currentFrame;

    GLfloat cameraSpeed = 1.0f * deltaTime;
    if (keys[GLFW_KEY_W])
        camera.ProcessKeyboard(Camera_Movement(FORWARD), deltaTime);
    if (keys[GLFW_KEY_S])
        camera.ProcessKeyboard(Camera_Movement(BACKWARD), deltaTime);
    if (keys[GLFW_KEY_A])
        camera.ProcessKeyboard(Camera_Movement(LEFT), deltaTime);
    if (keys[GLFW_KEY_D])
        camera.ProcessKeyboard(Camera_Movement(RIGHT), deltaTime);
}

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
    if (action == GLFW_PRESS)           //如果當前是按下操作
        keys[key] = true;
    else if (action == GLFW_RELEASE)            //鬆開鍵盤
        keys[key] = false;
}

void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
    camera.ProcessMouseScroll(yoffset);
}

void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
    if (firstMouse)
    {
        lastX = xpos;
        lastY = ypos;
        firstMouse = false;
    }
    GLfloat xoffset = xpos - lastX;
    GLfloat yoffset = lastY - ypos;
    lastX = xpos;
    lastY = ypos;
    
    GLfloat sensitivity = 0.05;
    xoffset *= sensitivity;
    yoffset *= sensitivity;
    
    camera.ProcessMouseMovement(xoffset, yoffset);
}

儘管主代碼設置uniform變量時看起來很嚇人，但是在實際的運用上，這些參數肯定不可能是寫死的，而是讀取配置，但因爲這裏只考慮openGL的學習，所以寫死也沒有多大關係

 

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