基于C++的OpenGL 12 之多光源
2022/8/16 14:53:32
本文主要是介绍基于C++的OpenGL 12 之多光源，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！
1. 引言
本文基于C++语言，描述OpenGL的多光源
前置知识可参考：
- 基于C++的OpenGL 11 之投光物 - 当时明月在曾照彩云归 - 博客园 (cnblogs.com)
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：
- 多光源 - LearnOpenGL CN (learnopengl-cn.github.io)
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：
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：
- 基于C++的OpenGL 07 之颜色 - 当时明月在曾照彩云归 - 博客园 (cnblogs.com)
5. 参考资料
[1]多光源 - LearnOpenGL CN (learnopengl-cn.github.io)
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