环境光照添加到场景里非常简单，用光的颜色乘以一个很小的常量环境因子，再乘以物体的颜色，然后将最终结果作为片段的颜色：
void main(){ float ambientStrength = 0.1; vec3 ambient = ambientStrength * lightColor; vec3 result = ambient * objectColor; FragColor = vec4(result, 1.0);}漫反射的计算稍微复杂些，计算漫反射时需要
1.法向量：一个垂直于顶点表面的向量
2.定向的光线：作为光源的位置与片段的位置之间向量差的方向向量。为了计算这个光线，我们需要光的位置向量和片段的位置向量。
漫反射的计算
vec3 norm = normalize(Normal); vec3 lightDir = normalize(sunPos - FragPos); float diff = max(dot(norm, lightDir), 0.0); vec3 diffuse = diff * sunColor;完整demo代码如下：
#include "stdio.h"#include <GL/glew.h>#include <GLFW/glfw3.h>#include <soil/SOIL.h>#include <glm/glm.hpp>#include <glm/gtc/matrix_transform.hpp>#include <glm/gtc/type_ptr.hpp>#include <iostream>#include "wrapperWindow.h"#include "wrapperShader.h"#include "data.h"const int design_w = 800;const int design_h = 600;int main(){GLFWwindow *window = wrapperWindow(design_w, design_h).getWindow();auto m_shader = wrapperShader::createWithFilePath("triangle.vsh", "triangle.fsh");auto m_lightShader = wrapperShader::createWithFilePath("light.vsh", "light.fsh");int arr_group_nun = 6;GLuint vao, vbo;glGenVertexArrays(1, &vao);glBindVertexArray(vao);glGenBuffers(1, &vbo);glBindBuffer(GL_ARRAY_BUFFER,vbo);glBufferData(GL_ARRAY_BUFFER, sizeof(cubeNormalArr), cubeNormalArr, GL_STATIC_DRAW);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, arr_group_nun* sizeof(GLfloat), (GLvoid *)0);glEnableVertexAttribArray(0);glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, arr_group_nun* sizeof(GLfloat), (GLvoid *)(3 * sizeof(GLfloat)));glEnableVertexAttribArray(1);//--GLuint lightVao;glGenVertexArrays(1, &lightVao);glBindVertexArray(lightVao);glBindBuffer(GL_ARRAY_BUFFER, vbo);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, arr_group_nun* sizeof(GLfloat), (GLvoid *)0);glEnableVertexAttribArray(0);glBindBuffer(GL_ARRAY_BUFFER, 0);glBindVertexArray(0);//-----------//启用深度测试glEnable(GL_DEPTH_TEST);glm::vec3 lightPos(1.2f, 1.0f, 2.0f);while (!glfwWindowShouldClose(window)){glfwPollEvents();glClearColor(0.5f, 0.5f, 0.5f, 1.0f);glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);m_shader.useShaderProgram();m_shader.setVec3("objectColor", 1.0f, 0.5f, 0.31f);m_shader.setVec3("sunColor", 1.0f, 1.0f, 1.0f);m_shader.setVec3("sunPos", lightPos);glm::mat4 view;view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));m_shader.setMat4fv("view",view);glm::mat4 projection;projection = glm::perspective(glm::radians(45.0f), (float)(design_w*1.0 / design_h), 0.1f, 100.0f);m_shader.setMat4fv("projection", projection);glm::mat4 model;model = glm::rotate(model, (float)glfwGetTime()*glm::radians(25.0f), glm::vec3(1.0f, -1.0f, 0.0f));m_shader.setMat4fv("model", model);;glBindVertexArray(vao);//glBindTexture(GL_TEXTURE_2D,tex);glDrawArrays(GL_TRIANGLES, 0, 36);glBindVertexArray(0);//--m_lightShader.useShaderProgram();view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));m_lightShader.setMat4fv("view", view);projection = glm::perspective(glm::radians(45.0f), (float)(design_w*1.0 / design_h), 0.1f, 100.0f);m_lightShader.setMat4fv("projection", projection);model = glm::mat4();model = glm::translate(model, lightPos);model = glm::scale(model, glm::vec3(0.2f));m_lightShader.setMat4fv("model", model);glBindVertexArray(lightVao);glDrawArrays(GL_TRIANGLES, 0, 36);glBindVertexArray(0);glfwSwapBuffers(window);}glfwTerminate();return 0;}效果图：