OpenGL学习笔记——光照(二)

叁歲伎倆 2023-01-15 08:30 172阅读 0赞

继续开始OpenGL的学习之旅，不得不说《Learning OpenGL》一书讲的是真的非常好，可以多读几遍\*~\*。

### 文章目录 ###

*  一、材质
 *  二、光照贴图
 *   *  2.1漫反射贴图
     *  2.2镜面贴图

# 一、材质 #

> 继续上一篇文章内容，其实这里的材质主要是指物体反射光的能力，如石头、铁块等等，使用同一束光去照射他们，他们会产生不同大小的光斑。

实现代码：

> shader\_materials.vs

#version 330 core
    layout (location = 0) in vec3 aPos;
    layout (location = 1) in vec3 aNormal;
    
    out vec3 FragPos;
    out vec3 Normal;
    
    uniform mat4 model;
    uniform mat4 view;
    uniform mat4 projection;
    
    void main()
    { 
        FragPos = vec3(model * vec4(aPos, 1.0));		//将局部坐标系中的坐标转化到世界坐标系中，也就求出了片元位置
        Normal = mat3(transpose(inverse(model))) * aNormal;  	//使用正规矩阵来变换法向量
        
        gl_Position = projection * view * vec4(FragPos, 1.0);
    }

> shader\_materials.fs

#version 330 core
    out vec4 FragColor;
    
    struct Material { 	//材质结构
    	vec3 ambient;
    	vec3 diffuse;
    	vec3 specular;    
    	float shininess;
    }; 
    
    struct Light { 		//光源的结构
        vec3 position;
    
        vec3 ambient;
        vec3 diffuse;
        vec3 specular;
    };
    
    in vec3 FragPos;  
    in vec3 Normal;  
      
    uniform vec3 viewPos;
    uniform Material material;
    uniform Light light;
    
    void main()
    { 
        //环境光
        vec3 ambient = light.ambient * material.ambient;
      	
        //散射光 
        vec3 norm = normalize(Normal);
        vec3 lightDir = normalize(light.position - FragPos);
        float diff = max(dot(norm, lightDir), 0.0);
        vec3 diffuse = light.diffuse * (diff * material.diffuse);
        
        //镜面光
        vec3 viewDir = normalize(viewPos - FragPos);
        vec3 reflectDir = reflect(-lightDir, norm);  
        float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
        vec3 specular = light.specular * (spec * material.specular);  
            
        vec3 result = ambient + diffuse + specular;
        FragColor = vec4(result, 1.0);
    }

> \#Practice.h

void lightv4() { 
    		glfwInit();
    		glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    		glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    		glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    
    		GLFWwindow *window = glfwCreateWindow(800, 600, "Light", 0, 0);
    		if (window == NULL) { 
    			std::cout << "Creating window is failed" << std::endl;
    			glfwTerminate();
    			return;
    		}
    
    		glfwMakeContextCurrent(window);
    		glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    		glfwSetCursorPosCallback(window, mouse_callback);
    		glfwSetScrollCallback(window, scroll_callback);
    		glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_NORMAL);
    
    		if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    		{ 
    			std::cout << "Failed to initialize GLAD" << std::endl;
    			return;
    		}
    
    		int viewWidth, viewHeight;
    		glfwGetFramebufferSize(window, &viewWidth, &viewHeight);
    		glViewport(0, 0, viewWidth, viewHeight);
    
    		Shader colorShader("../Shader/shader_materials.vs", "../Shader/shader_materials.fs");
    		Shader cubeShader("../Shader/shader_light_cube.vs", "../Shader/shader_light_cube.fs");
    
    		//顶点数据
    		float vertices[] = { 
    			-0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    			0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    			0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    			0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    			-0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    			-0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    
    			-0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,
    			0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,
    			0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,
    			0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,
    			-0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,
    			-0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,
    
    			-0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
    			-0.5f,  0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
    			-0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
    			-0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
    			-0.5f, -0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
    			-0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
    
    			0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
    			0.5f,  0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
    			0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
    			0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
    			0.5f, -0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
    			0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
    
    			-0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
    			0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
    			0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
    			0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
    			-0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
    			-0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
    
    			-0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
    			0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
    			0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
    			0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
    			-0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
    			-0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f
    		};
    
    		//为数据分配缓冲区
    		unsigned int colorVAO, VBO;
    		glGenVertexArrays(1, &colorVAO);
    		glBindVertexArray(colorVAO);
    
    		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, 6 * sizeof(float), (void*)0);
    		glEnableVertexAttribArray(0);
    		glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    		glEnableVertexAttribArray(1);
    
    		unsigned int cubeVAO;
    		glGenVertexArrays(1, &cubeVAO);
    		glBindVertexArray(cubeVAO);
    		glBindBuffer(GL_ARRAY_BUFFER, VBO);
    		glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    		glEnableVertexAttribArray(0);
    
    		//光源的位置
    		glm::vec3 lightPos(1.2f, 1.0f, -2.0f);
    
    		while (!glfwWindowShouldClose(window)) { 
    			float currentFrame = glfwGetTime();
    			deltaTime = currentFrame - lastFrame;
    			lastFrame = currentFrame;
    			glEnable(GL_DEPTH_TEST);
    			processInput(window);
    
    			glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
    			glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    			glm::mat4 model = glm::mat4(1.0f);
    			glm::mat4 view = glm::mat4(1.0f);
    			glm::mat4 projection = glm::mat4(1.0f);
    
    			//绘制有颜色的立方体
    			colorShader.use();
    			colorShader.setVec3("light.position", lightPos);		//设置光的位置
    			colorShader.setVec3("viewPos", camera.Position);	//将相机位置（人眼位置）传递给着色器
    
    			//设置光的属性，如光的颜色、强度等
    			colorShader.setVec3("light.ambient", glm::vec3(1.0f));		//环境光强，这也算是一种权重
    			colorShader.setVec3("light.diffuse", glm::vec3(1.0f));		//反射光强
    			colorShader.setVec3("light.specular", glm::vec3(1.0f));		//镜面光强
    
    			//设置物体的材质属性
    			colorShader.setVec3("material.ambient", 1.0f, 0.5f, 0.31f);		//物体的颜色
    			colorShader.setVec3("material.diffuse", 1.0f, 0.5f, 0.31f);		//物体颜色
    			colorShader.setVec3("material.specular", 0.5f, 0.5f, 0.5f);
    			colorShader.setFloat("material.shininess", 32.0f);
    
    			projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
    			view = camera.GetViewMatrix();
    			colorShader.setMat4("projection", projection);
    			colorShader.setMat4("view", view);
    			colorShader.setMat4("model", model);
    			glBindVertexArray(colorVAO);
    			glDrawArrays(GL_TRIANGLES, 0, 36);
    
    			cubeShader.use();
    			//view = glm::translate(view, glm::vec3(0.0f, 0.0f, -10.0f));
    			//view = glm::lookAt(glm::vec3(0.0f, 0.0f, 10.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
    			cubeShader.setMat4("projection", projection);
    			cubeShader.setMat4("view", view);
    			model = glm::mat4(1.0f);
    			model = glm::translate(model, lightPos);		//将灯平移到lightPos位置
    			model = glm::scale(model, glm::vec3(0.2f));		//并对其进行一定程度的缩放
    			cubeShader.setMat4("model", model);
    			glBindVertexArray(cubeVAO);
    			glDrawArrays(GL_TRIANGLES, 0, 36);
    
    			glfwSwapBuffers(window);
    			glfwPollEvents();
    		}
    		glDeleteVertexArrays(1, &colorVAO);
    		glDeleteVertexArrays(1, &cubeVAO);
    		glDeleteBuffers(1, &VBO);
    
    		glfwTerminate();
    	}

运行效果：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70]

> 就实现过程而言，其实就是对材质和光源更为细化，像之前的光源我们是只给了颜色和位置，但是却没有给它指定它自身的强度等等信息。现在填上这些信息可以更好的控制物体表面的一些颜色变化，因此我们可以实现一些很有趣的效果。

在窗口的循环中稍作修改：

//设置光的属性，如光的颜色、强度等
    	glm::vec3 lightColor;
    	lightColor.x = sin(glfwGetTime() * 2.0f);
    	lightColor.y = sin(glfwGetTime() * 0.7f);
    	lightColor.z = sin(glfwGetTime() * 1.3f);
    	glm::vec3 diffuseColor = lightColor   * glm::vec3(0.5f); // decrease the influence
    	glm::vec3 ambientColor = diffuseColor * glm::vec3(0.2f); // low influence
    	colorShader.setVec3("light.ambient", ambientColor);	//环境光强，这也算是一种权重
    	colorShader.setVec3("light.diffuse", diffuseColor);	//反射光强 
    	colorShader.setVec3("light.specular", glm::vec3(1.0f));		//镜面光强

修改一下相机和光源的位置：

> Camera camera(glm::vec3(2.0f, 1.0f, 5.0f));  
> glm::vec3 lightPos(1.2f, 1.0f, 2.0f);

![在这里插入图片描述][20210422165126717.gif]

# 二、光照贴图 #

## 2.1漫反射贴图 ##

> 这部分与纹理贴图那部分内容其实是一样的，只不过是将我们设定好的颜色变为相应的纹理采样器即可，如下所示。

实现代码：

> shader\_lighting\_maps.vs

#version 330 core
    layout (location = 0) in vec3 aPos;
    layout (location = 1) in vec3 aNormal;
    layout (location = 2) in vec2 aTexCoords;
    
    out vec3 FragPos;
    out vec3 Normal;
    out vec2 TexCoords;
    
    uniform mat4 model;
    uniform mat4 view;
    uniform mat4 projection;
    
    void main()
    { 
        FragPos = vec3(model * vec4(aPos, 1.0));		//将局部坐标系中的坐标转化到世界坐标系中，也就求出了片元位置
        Normal = mat3(transpose(inverse(model))) * aNormal;  	//使用正规矩阵来变换法向量
    	TexCoords = aTexCoords;
        
        gl_Position = projection * view * vec4(FragPos, 1.0);
    }

> shader\_lighting\_maps.fs

#version 330 core
    out vec4 FragColor;
    
    struct Material { 
        sampler2D diffuse;
        vec3 specular;    
        float shininess;
    }; 
    
    struct Light { 
        vec3 position;
    
        vec3 ambient;
        vec3 diffuse;
        vec3 specular;
    };
    
    in vec3 FragPos;  
    in vec3 Normal;  
    in vec2 TexCoords;
      
    uniform vec3 viewPos;
    uniform Material material;
    uniform Light light;
    
    void main()
    { 
        //环境光
        vec3 ambient = light.ambient * texture(material.diffuse, TexCoords).rgb;
      	
        //反射光
        vec3 norm = normalize(Normal);
        vec3 lightDir = normalize(light.position - FragPos);
        float diff = max(dot(norm, lightDir), 0.0);
        vec3 diffuse = light.diffuse * diff * texture(material.diffuse, TexCoords).rgb;  
        
        //镜面光
        vec3 viewDir = normalize(viewPos - FragPos);
        vec3 reflectDir = reflect(-lightDir, norm);  
        float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
        vec3 specular = light.specular * (spec * material.specular);  
            
        vec3 result = ambient + diffuse + specular;
        FragColor = vec4(result, 1.0);
    }

> Practice.h文件中修改的部分：

unsigned int loadTexture(char const * path)
    	{ 
    		unsigned int textureID;
    		glGenTextures(1, &textureID);
    
    		int width, height, nrComponents;
    		unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
    		if (data)
    		{ 
    			GLenum format;
    			if (nrComponents == 1)
    				format = GL_RED;
    			else if (nrComponents == 3)
    				format = GL_RGB;
    			else if (nrComponents == 4)
    				format = GL_RGBA;
    
    			glBindTexture(GL_TEXTURE_2D, textureID);
    			glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
    			glGenerateMipmap(GL_TEXTURE_2D);
    
    			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_LINEAR);
    
    			stbi_image_free(data);
    		}
    		else
    		{ 
    			std::cout << "Texture failed to load at path: " << path << std::endl;
    			stbi_image_free(data);
    		}
    
    		return textureID;
    	}

Shader colorShader("../Shader/shader_lighting_maps.vs", "../Shader/shader_lighting_maps.fs");

//顶点数据
    		float 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
    		};

//改变顶点数据
    		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);
    		
    		unsigned int cubeVAO;
    		glGenVertexArrays(1, &cubeVAO);
    		glBindVertexArray(cubeVAO);
    		glBindBuffer(GL_ARRAY_BUFFER, VBO);
    		glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    		glEnableVertexAttribArray(0);
    		
    		//加载图像
    		unsigned int diffuseMap = loadTexture("container2.png");

//设置光的属性，如光的颜色、强度等
    		colorShader.setVec3("light.ambient", glm::vec3(0.2f));	//环境光强，这也算是一种权重
    		colorShader.setVec3("light.diffuse", glm::vec3(0.5f));	//反射光强 
    		colorShader.setVec3("light.specular", glm::vec3(1.0f));		//镜面光强
    
    		//设置物体的材质属性
    		colorShader.setVec3("material.specular", 0.5f, 0.5f, 0.5f);
    		colorShader.setFloat("material.shininess", 64.0f);

glActiveTexture(GL_TEXTURE0);
    		glBindTexture(GL_TEXTURE_2D, diffuseMap);

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 1]

## 2.2镜面贴图 ##

> 上面的结果虽已具备了三维模型的雏形，但仍存在一个问题，那就是不同的材质应该拥有不同的镜面反射能力，如果给箱子的边缘加一层铁皮，那么又当是什么效果呢，这里可以做一些尝试。

代码修改部分：

> shader\_lighting\_maps\_specular.fs

#version 330 core
    out vec4 FragColor;
    
    struct Material { 
        sampler2D diffuse;
        sampler2D specular;    
        float shininess;
    }; 
    
    struct Light { 
        vec3 position;
    
        vec3 ambient;
        vec3 diffuse;
        vec3 specular;
    };
    
    in vec3 FragPos;  
    in vec3 Normal;  
    in vec2 TexCoords;
      
    uniform vec3 viewPos;
    uniform Material material;
    uniform Light light;
    
    void main()
    { 
        //环境光
        vec3 ambient = light.ambient * texture(material.diffuse, TexCoords).rgb;
      	
        //反射光
        vec3 norm = normalize(Normal);
        vec3 lightDir = normalize(light.position - FragPos);
        float diff = max(dot(norm, lightDir), 0.0);
        vec3 diffuse = light.diffuse * diff * texture(material.diffuse, TexCoords).rgb;  
        
        //镜面光
        vec3 viewDir = normalize(viewPos - FragPos);
        vec3 reflectDir = reflect(-lightDir, norm);  
        float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
        vec3 specular = light.specular * spec * texture(material.specular,TexCoords).rgb;  
            
        vec3 result = ambient + diffuse + specular;
        FragColor = vec4(result, 1.0);
    }

> Practice.h

//加载图像
    		unsigned int diffuseMap = loadTexture("container2.png");
    		unsigned int specularMap = loadTexture("container2_specular.png");
    
    		colorShader.use();
    		colorShader.setInt("material.diffuse", 0);
    		colorShader.setInt("material.specular", 1);

glActiveTexture(GL_TEXTURE0);
    		glBindTexture(GL_TEXTURE_2D, diffuseMap);
    
    		glActiveTexture(GL_TEXTURE1);
    		glBindTexture(GL_TEXTURE_2D, specularMap);

不过实现的效果却不甚理想，不知道是什么原因，物体表面并没有明显的光斑出现（和书中的效果不同），如下图所示（等日后再找一找其中的缘由\*^\*）：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 2]

即使单独测试了一下铁皮外壳，仍然是没有明显的光斑，真是奇怪啊\*^\*。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 3]

不过，在后续的多光源实验中则可以看出明显的效果：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 4]

> 参考资料：[《Learning OpenGL》][Learning OpenGL]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70]: /images/20221022/5b1ca909d4414fb0b5b35030d9d30b4f.png
[20210422165126717.gif]: /images/20221022/d6eacda224b0479aa516156bce4304ec.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 1]: /images/20221022/dddf48f1d4e248d0a69f6c24a6ac938d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 2]: /images/20221022/9badeacfa7384ecd877db03d736e3e30.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 3]: /images/20221022/123bc0e2970c4807b9f1e5c9b0394720.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RheXVoYWl0YW5nMQ_size_16_color_FFFFFF_t_70 4]: /images/20221022/60263c3a1103465dad934d9ca9ac515e.png
[Learning OpenGL]: https://learnopengl-cn.readthedocs.io/zh/latest/