ICode9
精准搜索请尝试： 精确搜索
首页
编程语言>
数据库
系统相关
互联网
其他分享
Python
Java
JavaScript
android
PHP
首页 > 编程语言> 文章详细

基于C++的OpenGL 12 之多光源

2022-08-16 13:32:13  阅读：191  来源： 互联网

标签：pointLights 12 1.0 OpenGL light C++ vec3 lightingShader diffuse


1. 引言

本文基于C++语言，描述OpenGL的多光源

前置知识可参考：

笔者这里不过多描述每个名词、函数和细节，更详细的文档可以参考：

2. 概述

生活中，光源往往是不止一个的，通常是多个光源同时出现

3. 编码

使用多个光源时，将光照计算代码全写在片段着色器的main函数里，不利于代码的编写与阅读

在这里，将多个光照封装为GLSL中的函数

平行光照函数：

struct DirLight {
    vec3 direction;

    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};  
    
uniform DirLight dirLight;

vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir);

void main()
{
    ...
}

vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir)
{
    vec3 lightDir = normalize(-light.direction);
    // 漫反射着色
    float diff = max(dot(normal, lightDir), 0.0);
    // 镜面光着色
    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    // 合并结果
    vec3 ambient  = light.ambient  * vec3(texture(material.diffuse, TexCoords));
    vec3 diffuse  = light.diffuse  * diff * vec3(texture(material.diffuse, TexCoords));
    vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
    return (ambient + diffuse + specular);
}

点光照函数：

struct PointLight {
    vec3 position;

    float constant;
    float linear;
    float quadratic;

    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};  
#define NR_POINT_LIGHTS 4
uniform PointLight pointLights[NR_POINT_LIGHTS]; // 定义四个点光源

vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir);

void main()
{
    ...
}

vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
    vec3 lightDir = normalize(light.position - fragPos);
    // 漫反射着色
    float diff = max(dot(normal, lightDir), 0.0);
    // 镜面光着色
    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    // 衰减
    float distance    = length(light.position - fragPos);
    float attenuation = 1.0 / (light.constant + light.linear * distance + 
                 light.quadratic * (distance * distance));    
    // 合并结果
    vec3 ambient  = light.ambient  * vec3(texture(material.diffuse, TexCoords));
    vec3 diffuse  = light.diffuse  * diff * vec3(texture(material.diffuse, TexCoords));
    vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
    ambient  *= attenuation;
    diffuse  *= attenuation;
    specular *= attenuation;
    return (ambient + diffuse + specular);
}

合并光照：

void main()
{
    // 属性
    vec3 norm = normalize(Normal);
    vec3 viewDir = normalize(viewPos - FragPos);

    // 第一阶段：定向光照
    vec3 result = CalcDirLight(dirLight, norm, viewDir);
    // 第二阶段：点光源
    for(int i = 0; i < NR_POINT_LIGHTS; i++)
        result += CalcPointLight(pointLights[i], norm, FragPos, viewDir);    
    // 第三阶段：聚光
    //result += CalcSpotLight(spotLight, norm, FragPos, viewDir);    

    FragColor = vec4(result, 1.0);
}

向GPU传输数据：

// positions of the point lights
glm::vec3 pointLightPositions[] = {
    glm::vec3( 0.7f,  0.2f,  2.0f),
    glm::vec3( 2.3f, -3.3f, -4.0f),
    glm::vec3(-4.0f,  2.0f, -12.0f),
    glm::vec3( 0.0f,  0.0f, -3.0f)
};
...
// directional light
lightingShader.setVec3("dirLight.direction", -0.2f, -1.0f, -0.3f);
lightingShader.setVec3("dirLight.ambient", 0.05f, 0.05f, 0.05f);
lightingShader.setVec3("dirLight.diffuse", 0.4f, 0.4f, 0.4f);
lightingShader.setVec3("dirLight.specular", 0.5f, 0.5f, 0.5f);
// point light 1
lightingShader.setVec3("pointLights[0].position", pointLightPositions[0]);
lightingShader.setVec3("pointLights[0].ambient", 0.05f, 0.05f, 0.05f);
lightingShader.setVec3("pointLights[0].diffuse", 0.8f, 0.8f, 0.8f);
lightingShader.setVec3("pointLights[0].specular", 1.0f, 1.0f, 1.0f);
lightingShader.setFloat("pointLights[0].constant", 1.0f);
lightingShader.setFloat("pointLights[0].linear", 0.09f);
lightingShader.setFloat("pointLights[0].quadratic", 0.032f);
// point light 2
lightingShader.setVec3("pointLights[1].position", pointLightPositions[1]);
lightingShader.setVec3("pointLights[1].ambient", 0.05f, 0.05f, 0.05f);
lightingShader.setVec3("pointLights[1].diffuse", 0.8f, 0.8f, 0.8f);
lightingShader.setVec3("pointLights[1].specular", 1.0f, 1.0f, 1.0f);
lightingShader.setFloat("pointLights[1].constant", 1.0f);
lightingShader.setFloat("pointLights[1].linear", 0.09f);
lightingShader.setFloat("pointLights[1].quadratic", 0.032f);
// point light 3
lightingShader.setVec3("pointLights[2].position", pointLightPositions[2]);
lightingShader.setVec3("pointLights[2].ambient", 0.05f, 0.05f, 0.05f);
lightingShader.setVec3("pointLights[2].diffuse", 0.8f, 0.8f, 0.8f);
lightingShader.setVec3("pointLights[2].specular", 1.0f, 1.0f, 1.0f);
lightingShader.setFloat("pointLights[2].constant", 1.0f);
lightingShader.setFloat("pointLights[2].linear", 0.09f);
lightingShader.setFloat("pointLights[2].quadratic", 0.032f);
// point light 4
lightingShader.setVec3("pointLights[3].position", pointLightPositions[3]);
lightingShader.setVec3("pointLights[3].ambient", 0.05f, 0.05f, 0.05f);
lightingShader.setVec3("pointLights[3].diffuse", 0.8f, 0.8f, 0.8f);
lightingShader.setVec3("pointLights[3].specular", 1.0f, 1.0f, 1.0f);
lightingShader.setFloat("pointLights[3].constant", 1.0f);
lightingShader.setFloat("pointLights[3].linear", 0.09f);
lightingShader.setFloat("pointLights[3].quadratic", 0.032f);
// spotLight
lightingShader.setVec3("spotLight.position", camera.Position);
lightingShader.setVec3("spotLight.direction", camera.Front);
lightingShader.setVec3("spotLight.ambient", 0.0f, 0.0f, 0.0f);
lightingShader.setVec3("spotLight.diffuse", 1.0f, 1.0f, 1.0f);
lightingShader.setVec3("spotLight.specular", 1.0f, 1.0f, 1.0f);
lightingShader.setFloat("spotLight.constant", 1.0f);
lightingShader.setFloat("spotLight.linear", 0.09f);
lightingShader.setFloat("spotLight.quadratic", 0.032f);
lightingShader.setFloat("spotLight.cutOff", glm::cos(glm::radians(12.5f)));
lightingShader.setFloat("spotLight.outerCutOff", glm::cos(glm::radians(15.0f)));

结果图如下：

image-20220816131348811

4. 完整代码

主要文件MultipleLights.cpp：

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <math.h>
#include "Shader.hpp"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include <glm/glm.hpp>
#include <glm/ext/matrix_transform.hpp>  // glm::translate, glm::rotate, glm::scale
#include <glm/ext/matrix_clip_space.hpp> // glm::perspective
#include <glm/gtc/type_ptr.hpp>

//全局变量
glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 10.0f);
glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);
glm::vec3 lightPos(0.8f, 1.0f, 2.0f);

// 函数声明
void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void process_input(GLFWwindow *window);


int main()
{
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    GLFWwindow *window = glfwCreateWindow(800, 600, "MultipleLights", nullptr, nullptr);

    if (window == nullptr)
    {
        std::cout << "Faild to create window" << std::endl;
        glfwTerminate();
    }
    glfwMakeContextCurrent(window);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Faild to initialize glad" << std::endl;
        return -1;
    }
    glad_glViewport(0, 0, 800, 600);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    //配置项
    glEnable(GL_DEPTH_TEST);

    Shader lightCubeShader("../light_cube.vs.glsl", "../light_cube.fs.glsl");
    Shader lightingShader("../cube.vs.glsl", "../cube.fs.glsl");

    unsigned int cubeVAO;
    glGenVertexArrays(1, &cubeVAO);
    glBindVertexArray(cubeVAO);

    float vertices[] = {
    // positions          // normals           // texture coords
    -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;
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(3*sizeof(float)));
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(6*sizeof(float)));
    glEnableVertexAttribArray(2);

    // 纹理
    unsigned int texture;
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    // 为当前绑定的纹理对象设置环绕、过滤方式
    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);
    // 加载并生成纹理
    int width, height, nrChannels;
    unsigned char *data = stbi_load("../container2.png", &width, &height, &nrChannels, 0);
    if (data)
    {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 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);
    lightingShader.setInt("material.diffuse", 0);

    // 镜面反射纹理
    unsigned int texture1;
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);
    // 为当前绑定的纹理对象设置环绕、过滤方式
    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);
    // 加载并生成纹理
    data = stbi_load("../container2_specular.png", &width, &height, &nrChannels, 0);
    if (data)
    {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 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);
    lightingShader.setInt("material.diffuse", 1);

    unsigned int lightCubeVAO;
    glGenVertexArrays(1, &lightCubeVAO);
    glBindVertexArray(lightCubeVAO);
    // 只需要绑定VBO不用再次设置VBO的数据，因为箱子的VBO数据中已经包含了正确的立方体顶点数据
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    // 设置灯立方体的顶点属性（对我们的灯来说仅仅只有位置数据）
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    // positions all containers
    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)
    };

    // positions of the point lights
    glm::vec3 pointLightPositions[] = {
        glm::vec3( 0.7f,  0.2f,  2.0f),
        glm::vec3( 2.3f, -3.3f, -4.0f),
        glm::vec3(-4.0f,  2.0f, -12.0f),
        glm::vec3( 0.0f,  0.0f, -3.0f)
    };
    while (!glfwWindowShouldClose(window))
    {
        process_input(window);

        glClearColor(0.0, 0.0, 0.0, 1.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

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

        lightingShader.use();
        lightingShader.setVec3("objectColor", 1.0f, 0.5f, 0.31f);
        lightingShader.setVec3("lightColor", 1.0f, 1.0f, 1.0f);
        lightingShader.setVec3("lightPos", lightPos);
        lightingShader.setVec3("viewPos", cameraPos);
        lightingShader.setFloat("material.shininess", 32.0f);

        // directional light
        lightingShader.setVec3("dirLight.direction", -0.2f, -1.0f, -0.3f);
        lightingShader.setVec3("dirLight.ambient", 0.05f, 0.05f, 0.05f);
        lightingShader.setVec3("dirLight.diffuse", 0.4f, 0.4f, 0.4f);
        lightingShader.setVec3("dirLight.specular", 0.5f, 0.5f, 0.5f);
        // point light 1
        lightingShader.setVec3("pointLights[0].position", pointLightPositions[0]);
        lightingShader.setVec3("pointLights[0].ambient", 0.05f, 0.05f, 0.05f);
        lightingShader.setVec3("pointLights[0].diffuse", 0.8f, 0.8f, 0.8f);
        lightingShader.setVec3("pointLights[0].specular", 1.0f, 1.0f, 1.0f);
        lightingShader.setFloat("pointLights[0].constant", 1.0f);
        lightingShader.setFloat("pointLights[0].linear", 0.09f);
        lightingShader.setFloat("pointLights[0].quadratic", 0.032f);
        // point light 2
        lightingShader.setVec3("pointLights[1].position", pointLightPositions[1]);
        lightingShader.setVec3("pointLights[1].ambient", 0.05f, 0.05f, 0.05f);
        lightingShader.setVec3("pointLights[1].diffuse", 0.8f, 0.8f, 0.8f);
        lightingShader.setVec3("pointLights[1].specular", 1.0f, 1.0f, 1.0f);
        lightingShader.setFloat("pointLights[1].constant", 1.0f);
        lightingShader.setFloat("pointLights[1].linear", 0.09f);
        lightingShader.setFloat("pointLights[1].quadratic", 0.032f);
        // point light 3
        lightingShader.setVec3("pointLights[2].position", pointLightPositions[2]);
        lightingShader.setVec3("pointLights[2].ambient", 0.05f, 0.05f, 0.05f);
        lightingShader.setVec3("pointLights[2].diffuse", 0.8f, 0.8f, 0.8f);
        lightingShader.setVec3("pointLights[2].specular", 1.0f, 1.0f, 1.0f);
        lightingShader.setFloat("pointLights[2].constant", 1.0f);
        lightingShader.setFloat("pointLights[2].linear", 0.09f);
        lightingShader.setFloat("pointLights[2].quadratic", 0.032f);
        // point light 4
        lightingShader.setVec3("pointLights[3].position", pointLightPositions[3]);
        lightingShader.setVec3("pointLights[3].ambient", 0.05f, 0.05f, 0.05f);
        lightingShader.setVec3("pointLights[3].diffuse", 0.8f, 0.8f, 0.8f);
        lightingShader.setVec3("pointLights[3].specular", 1.0f, 1.0f, 1.0f);
        lightingShader.setFloat("pointLights[3].constant", 1.0f);
        lightingShader.setFloat("pointLights[3].linear", 0.09f);
        lightingShader.setFloat("pointLights[3].quadratic", 0.032f);
        // spotLight
        lightingShader.setVec3("spotLight.position", cameraPos);
        lightingShader.setVec3("spotLight.direction", cameraFront);
        lightingShader.setVec3("spotLight.ambient", 0.0f, 0.0f, 0.0f);
        lightingShader.setVec3("spotLight.diffuse", 1.0f, 1.0f, 1.0f);
        lightingShader.setVec3("spotLight.specular", 1.0f, 1.0f, 1.0f);
        lightingShader.setFloat("spotLight.constant", 1.0f);
        lightingShader.setFloat("spotLight.linear", 0.09f);
        lightingShader.setFloat("spotLight.quadratic", 0.032f);
        lightingShader.setFloat("spotLight.cutOff", glm::cos(glm::radians(12.5f)));
        lightingShader.setFloat("spotLight.outerCutOff", glm::cos(glm::radians(15.0f)));     

        glm::mat4 model = glm::mat4(1.0f);
        model = glm::rotate(model, glm::radians(-55.0f), glm::vec3(1.0f, 0.0f, 0.0f));

        glm::mat4 view = glm::mat4(1.0f);
        // view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
        view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);

        glm::mat4 projection = glm::mat4(1.0f);
        projection = glm::perspective(glm::radians(45.0f), 800.0f / 600.0f, 0.1f, 100.0f);

        // 模型矩阵
        int modelLoc = glGetUniformLocation(lightingShader.ID, "model");
        glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
        // 观察矩阵和投影矩阵与之类似
        int viewLoc = glGetUniformLocation(lightingShader.ID, "view");
        glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
        int projectionLoc = glGetUniformLocation(lightingShader.ID, "projection");
        glUniformMatrix4fv(projectionLoc, 1, GL_FALSE, glm::value_ptr(projection));

        // render the cube
        glBindVertexArray(cubeVAO);
        // glDrawArrays(GL_TRIANGLES, 0, 36);
        for (unsigned int i = 0; i < 10; i++)
        {
            // calculate the model matrix for each object and pass it to shader before drawing
            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));
            lightingShader.setMat4("model", model);

            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        // also draw the lamp object
        // lightCubeShader.use();
        // lightCubeShader.setMat4("projection", projection);
        // lightCubeShader.setMat4("view", view);
        // model = glm::mat4(1.0f);
        // model = glm::translate(model, lightPos);
        // model = glm::scale(model, glm::vec3(0.2f)); // a smaller cube
        // lightCubeShader.setMat4("model", model);

        // glBindVertexArray(lightCubeVAO);
        // glDrawArrays(GL_TRIANGLES, 0, 36);
        
        // also draw the lamp object(s)
         lightCubeShader.use();
         lightCubeShader.setMat4("projection", projection);
         lightCubeShader.setMat4("view", view);
    
         // we now draw as many light bulbs as we have point lights.
         glBindVertexArray(lightCubeVAO);
         for (unsigned int i = 0; i < 4; i++)
         {
             model = glm::mat4(1.0f);
             model = glm::translate(model, pointLightPositions[i]);
             model = glm::scale(model, glm::vec3(0.2f)); // Make it a smaller cube
             lightCubeShader.setMat4("model", model);
             glDrawArrays(GL_TRIANGLES, 0, 36);
         }

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}

void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{
    glViewport(0, 0, width, height);
}

void process_input(GLFWwindow *window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    {
        glfwSetWindowShouldClose(window, true);
    }
    float cameraSpeed = 0.05f; // adjust accordingly
    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;
}

立方体顶点着色器GLSLcube.vs.glsl：

#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
layout (location = 2) in vec2 aTexCoords;

out vec3 Normal;
out vec3 FragPos;  
out vec2 TexCoords;

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

void main()
{
    gl_Position = projection * view * model * vec4(aPos, 1.0);
    FragPos = vec3(model * vec4(aPos, 1.0));
    Normal = aNormal;
    TexCoords = aTexCoords;
}

立方体片段着色器GLSLcube.fs.glsl：

#version 330 core
struct Material {
    sampler2D diffuse;
    sampler2D specular;
    float     shininess;
}; 
struct DirLight {
    vec3 direction;

    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};  
    
uniform DirLight dirLight;

vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir);

struct PointLight {
    vec3 position;

    float constant;
    float linear;
    float quadratic;

    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};  
#define NR_POINT_LIGHTS 4
uniform PointLight pointLights[NR_POINT_LIGHTS]; // 定义四个点光源

vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir);

in vec3 Normal;
in vec3 FragPos;
in vec2 TexCoords;

out vec4 FragColor;

uniform vec3 objectColor;
uniform vec3 lightColor;
uniform vec3 lightPos;
uniform vec3 viewPos;
uniform Material material;

void main()
{
    // 属性
    vec3 norm = normalize(Normal);
    vec3 viewDir = normalize(viewPos - FragPos);

    // 第一阶段：定向光照
    vec3 result = CalcDirLight(dirLight, norm, viewDir);
    // 第二阶段：点光源
    for(int i = 0; i < NR_POINT_LIGHTS; i++)
        result += CalcPointLight(pointLights[i], norm, FragPos, viewDir);    
    // 第三阶段：聚光
    //result += CalcSpotLight(spotLight, norm, FragPos, viewDir);    

    FragColor = vec4(result, 1.0);
}

vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir)
{
    vec3 lightDir = normalize(-light.direction);
    // 漫反射着色
    float diff = max(dot(normal, lightDir), 0.0);
    // 镜面光着色
    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    // 合并结果
    vec3 ambient  = light.ambient  * vec3(texture(material.diffuse, TexCoords));
    vec3 diffuse  = light.diffuse  * diff * vec3(texture(material.diffuse, TexCoords));
    vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
    return (ambient + diffuse + specular);
}

vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
    vec3 lightDir = normalize(light.position - fragPos);
    // 漫反射着色
    float diff = max(dot(normal, lightDir), 0.0);
    // 镜面光着色
    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    // 衰减
    float distance    = length(light.position - fragPos);
    float attenuation = 1.0 / (light.constant + light.linear * distance + 
                 light.quadratic * (distance * distance));    
    // 合并结果
    vec3 ambient  = light.ambient  * vec3(texture(material.diffuse, TexCoords));
    vec3 diffuse  = light.diffuse  * diff * vec3(texture(material.diffuse, TexCoords));
    vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
    ambient  *= attenuation;
    diffuse  *= attenuation;
    specular *= attenuation;
    return (ambient + diffuse + specular);
}

着色器Shader.hpp、光源顶点着色器GLSLlight_cube.vs.glsl、光源片段着色器GLSLlight_cube.fs.glsl见：

5. 参考资料

[1]多光源 - LearnOpenGL CN (learnopengl-cn.github.io)

标签：pointLights,12,1.0,OpenGL,light,C++,vec3,lightingShader,diffuse
来源： https://www.cnblogs.com/jiujiubashiyi/p/16591223.html

本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享；
2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关；
3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关；
4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除；
5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。

关于我们 | 联系我们 | 留言反馈

专注分享技术，共同学习，共同进步。侵权联系[81616952@qq.com]

Copyright (C)ICode9.com, All Rights Reserved.

ICode9版权所有