文章目录
- 材质
- 设置材质
- 光的属性
- 脚本实现
- 光照贴图
- 漫反射贴图
- 高光反射贴图
材质
材质本质是一个数据集,主要功能就是给渲染器提供数据和光照算法。
如果我们想要在OpenGL中模拟多种类型的物体,我们必须针对每种表面定义不同的材质(Material)属性。
我们可以分别为三个光照分量定义一个材质颜色(Material Color):环境光照(Ambient Lighting)
、漫反射光照(Diffuse Lighting)
和镜面光照(Specular Lighting)
。通过为每个分量指定一个颜色,我们就能够对表面的颜色输出有细粒度的控制了。
再添加一个反光度(Shininess)分量,设置材质属性:
#version 330 core
struct Material {vec3 ambient;vec3 diffuse;vec3 specular;float shininess;
};
//在片段着色器中,我们创建一个结构体(Struct)来储存物体的材质属性。
uniform Material material;
设置材质
可以通过设置适当的uniform来设置应用中物体。
GLSL中一个结构体在设置uniform时并无任何区别,结构体只是充当uniform变量们的一个命名空间。所以如果想填充这个结构体的话,我们必须设置每个单独的uniform,但要以结构体名为前缀:
lightingShader.setVec3("material.ambient", 1.0f, 0.5f, 0.31f);
lightingShader.setVec3("material.diffuse", 1.0f, 0.5f, 0.31f);
lightingShader.setVec3("material.specular", 0.5f, 0.5f, 0.5f);
lightingShader.setFloat("material.shininess", 32.0f);
光的属性
一个光源对它的ambient、diffuse和specular光照分量有着不同的强度。
- 环境光照通常被设置为一个比较低的强度,因为我们不希望环境光颜色太过主导。
- 光源的漫反射分量通常被设置为我们希望光所具有的那个颜色,通常是一个比较明亮的白色。
- 镜面光分量通常会保持为vec3(1.0),以最大强度发光。注意我们也将光源的位置向量加入了结构体。
为光照属性创建类似材质结构体:
struct Light {vec3 position;vec3 ambient;vec3 diffuse;vec3 specular;
};uniform Light light;
和材质uniform一样,我们需要更新片段着色器:
vec3 ambient = light.ambient * material.ambient;
vec3 diffuse = light.diffuse * (diff * material.diffuse);
vec3 specular = light.specular * (spec * material.specular);
脚本实现
创建材质的顶点着色器和片元着色器
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));//在顶点着色器中,我们可以使用inverse和transpose函数自己生成这个法线矩阵,这两个函数对所有类型矩阵都有效Normal = mat3(transpose(inverse(model))) * aNormal; gl_Position = projection * view * vec4(FragPos, 1.0);
}
materials.fs
#version 330 core
out vec4 FragColor;struct Material {vec3 ambient;vec3 diffuse;vec3 specular; float shininess;
}; struct Light {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()
{// ambientvec3 ambient = light.ambient * material.ambient;// diffuse 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);// specularvec3 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);
}
创建灯光的顶点着色器和片元着色器
light_mrt_cube.vs
#version 330 core
layout (location = 0) in vec3 aPos;uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;void main()
{gl_Position = projection * view * model * vec4(aPos, 1.0);
}
light_mrt_cube.fs
#version 330 core
out vec4 FragColor;void main()
{FragColor = vec4(1.0); // set all 4 vector values to 1.0
}
完整源码
#include <glad/glad.h>
#include <GLFW/glfw3.h>#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>#define STB_IMAGE_IMPLEMENTATION
#include <stb_image.h>// https://learnopengl.com/code_viewer_gh.php?code=includes/learnopengl/shader_m.h
#include <shader_s.h>
// https://learnopengl.com/code_viewer_gh.php?code=includes/learnopengl/camera.h
#include <camera.h>void InitGLFW();
bool CreateWindow();
bool InitGLAD();// 窗口大小改变时调用
void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void mouse_callback(GLFWwindow *window, double xposIn, double yposIn);
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset);
void processInput(GLFWwindow *window);// settings 窗口宽高
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;// 相机
Camera camera(glm::vec3(0.0f, 0.0f, 6.0f));
float lastX = static_cast<float>(SCR_WIDTH) / 2.0;
float lastY = static_cast<float>(SCR_HEIGHT) / 2.0;
bool firstMouse = true;// timing
float deltaTime = 0.0f; // time between current frame and last frame
float lastFrame = 0.0f;// lighting
glm::vec3 lightPos(0.5f, 0.5f, 1.0f);GLFWwindow *window;int main()
{InitGLFW(); // 初始化GLFWbool isCreated = CreateWindow(); // 创建一个窗口对象if (!isCreated)return -1;bool isGLAD = InitGLAD(); // 初始化GLAD,传入加载系统相关opengl函数指针的函数if (!isGLAD)return -1;// 启用深度测试glEnable(GL_DEPTH_TEST);// 构建和编译着色程序Shader lightingShader("shader/P1_Basic/08_LightModel/materials.vs", "shader/P1_Basic/08_LightModel/materials.fs");Shader lightCubeShader("shader/P1_Basic/08_LightModel/light_mrt_cube.vs", "shader/P1_Basic/08_LightModel/light_mrt_cube.fs");// 设置顶点数据(和缓冲区)并配置顶点属性// 1.设置立方体顶点输入 一共需要36个顶点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};// 2.设置索引缓冲对象unsigned int VBO, cubeVAO;glGenVertexArrays(1, &cubeVAO);glGenBuffers(1, &VBO);glBindBuffer(GL_ARRAY_BUFFER, VBO);glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);glBindVertexArray(cubeVAO);// position attributeglVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);glEnableVertexAttribArray(0);// normal attributeglVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));glEnableVertexAttribArray(1);// second, configure the light's VAO (VBO stays the same; the vertices are the same for the light object which is also a 3D cube)unsigned int lightCubeVAO;glGenVertexArrays(1, &lightCubeVAO);glBindVertexArray(lightCubeVAO);glBindBuffer(GL_ARRAY_BUFFER, VBO);// note that we update the lamp's position attribute's stride to reflect the updated buffer dataglVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);glEnableVertexAttribArray(0);// 循环渲染while (!glfwWindowShouldClose(window)){// 计算帧间隔时间float currentFrame = static_cast<float>(glfwGetTime());deltaTime = currentFrame - lastFrame;lastFrame = currentFrame;// 输入processInput(window);// 渲染// 清除颜色缓冲glClearColor(0.1f, 0.1f, 0.1f, 1.0f);// 清除深度缓冲glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);// be sure to activate shader when setting uniforms/drawing objectslightingShader.use();lightingShader.setVec3("light.position", lightPos);lightingShader.setVec3("viewPos", camera.Position);// light propertiesglm::vec3 lightColor;lightColor.x = static_cast<float>(sin(glfwGetTime() * 2.0));lightColor.y = static_cast<float>(sin(glfwGetTime() * 0.7));lightColor.z = static_cast<float>(sin(glfwGetTime() * 1.3));glm::vec3 diffuseColor = lightColor * glm::vec3(0.5f); // decrease the influenceglm::vec3 ambientColor = diffuseColor * glm::vec3(0.2f); // low influencelightingShader.setVec3("light.ambient", ambientColor);lightingShader.setVec3("light.diffuse", diffuseColor);lightingShader.setVec3("light.specular", 1.0f, 1.0f, 1.0f);// material propertieslightingShader.setVec3("material.ambient", 1.0f, 0.5f, 0.31f);lightingShader.setVec3("material.diffuse", 1.0f, 0.5f, 0.31f);lightingShader.setVec3("material.specular", 0.5f, 0.5f, 0.5f); // specular lighting doesn't have full effect on this object's materiallightingShader.setFloat("material.shininess", 32.0f);// view/projection transformationsglm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);glm::mat4 view = camera.GetViewMatrix();lightingShader.setMat4("projection", projection);lightingShader.setMat4("view", view);// world transformationglm::mat4 model = glm::mat4(1.2f);lightingShader.setMat4("model", model);// render the cubeglBindVertexArray(cubeVAO);glDrawArrays(GL_TRIANGLES, 0, 36);// also draw the lamp objectlightCubeShader.use();lightCubeShader.setMat4("projection", projection);lightCubeShader.setMat4("view", view);model = glm::mat4(0.6f);model = glm::translate(model, lightPos);model = glm::scale(model, glm::vec3(0.5f)); // a smaller cubelightCubeShader.setMat4("model", model);glBindVertexArray(lightCubeVAO);glDrawArrays(GL_TRIANGLES, 0, 36);// 检查并调用事件,交换缓冲glfwSwapBuffers(window);glfwPollEvents();}// 可选:一旦资源超出其用途,就取消分配所有资源:glDeleteVertexArrays(1, &cubeVAO);glDeleteVertexArrays(1, &lightCubeVAO);glDeleteBuffers(1, &VBO);// 释放/删除之前的分配的所有资源glfwTerminate();return 0;
}void InitGLFW()
{// 初始化GLFWglfwInit();// 配置GLFW 第一个参数代表选项的名称,我们可以从很多以GLFW_开头的枚举值中选择;// 第二个参数接受一个整型,用来设置这个选项的值。glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);// glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
}
bool CreateWindow()
{// 创建一个窗口对象window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);if (window == NULL){std::cout << "Failed to create GLFW window" << std::endl;// 创建失败,终止程序glfwTerminate();return false;}// 将我们窗口的上下文设置为当前线程的主上下文glfwMakeContextCurrent(window);// 设置窗口大小改变时的回调函数glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);// 设置鼠标移动回调函数glfwSetCursorPosCallback(window, mouse_callback);// 设置滚轮滚动回调函数glfwSetScrollCallback(window, scroll_callback);// 隐藏并捕捉鼠标// glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);return true;
}
bool InitGLAD()
{// 初始化GLAD,传入加载系统相关opengl函数指针的函数if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){std::cout << "Failed to initialize GLAD" << std::endl;// 初始化失败,终止程序return false;}return true;
}// 窗口大小改变时调用
void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{// 设置窗口的维度glViewport(0, 0, width, height);
}// 输入
void processInput(GLFWwindow *window)
{// 当用户按下esc键,我们设置window窗口的windowShouldClose属性为true// 关闭应用程序if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)glfwSetWindowShouldClose(window, true);if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)camera.ProcessKeyboard(FORWARD, deltaTime);if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)camera.ProcessKeyboard(BACKWARD, deltaTime);if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)camera.ProcessKeyboard(LEFT, deltaTime);if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)camera.ProcessKeyboard(RIGHT, deltaTime);
}// 鼠标移动回调函数
void mouse_callback(GLFWwindow *window, double xposIn, double yposIn)
{// 长按T键,鼠标才能控制相机if (glfwGetKey(window, GLFW_KEY_1) != GLFW_PRESS)return;float xpos = static_cast<float>(xposIn);float ypos = static_cast<float>(yposIn);if (firstMouse){lastX = xpos;lastY = ypos;firstMouse = false;}float xoffset = xpos - lastX;float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to toplastX = xpos;lastY = ypos;camera.ProcessMouseMovement(xoffset, yoffset);
}// 鼠标滚轮滚动回调函数
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset)
{camera.ProcessMouseScroll(static_cast<float>(yoffset));
}
运行效果:
光照贴图
纹理与贴图关系
事实上,纹理与贴图原理是一样的,贴图也叫纹理贴图,其实都是使用一张覆盖物体的图像,让我们能够逐片段索引其独立的颜色值。
漫反射贴图
只是在光照场景中,它通常叫做一个漫反射贴图(Diffuse Map)(3D艺术家通常都这么叫它),它是一个表现了物体所有的漫反射颜色的纹理图像。
在着色器中使用漫反射贴图的方法和纹理教程中是完全一样的。
但这次我们会将纹理储存为Material结构体中的一个sampler2D。我们将之前定义的vec3漫反射颜色向量替换为漫反射贴图:
struct Material {sampler2D diffuse;vec3 specular;float shininess;
};
...
in vec2 TexCoords;
注意sampler2D是所谓的不透明类型(Opaque Type),也就是说我们不能将它实例化,只能通过uniform来定义它。如果我们使用除uniform以外的方法(比如函数的参数)实例化这个结构体,GLSL会抛出一些奇怪的错误。这同样也适用于任何封装了不透明类型的结构体。
然后,我们将在片段着色器中再次需要纹理坐标,所以我们声明一个额外的输入变量。接下来我们只需要从纹理中采样片段的漫反射颜色值即可:
vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, TexCoords));
将环境光的材质颜色设置为漫反射材质颜色同样的值:
vec3 ambient = light.ambient * vec3(texture(material.diffuse, TexCoords));
脚本实现
创建顶点着色器和片元着色器
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));Normal = mat3(transpose(inverse(model))) * aNormal; TexCoords = aTexCoords;gl_Position = projection * view * vec4(FragPos, 1.0);
}
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()
{// ambientvec3 ambient = light.ambient * texture(material.diffuse, TexCoords).rgb;// diffuse 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; // specularvec3 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);
}
完整源码
#include <glad/glad.h>
#include <GLFW/glfw3.h>#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>#define STB_IMAGE_IMPLEMENTATION
#include <stb_image.h>// https://learnopengl.com/code_viewer_gh.php?code=includes/learnopengl/shader_m.h
#include <shader_s.h>
// https://learnopengl.com/code_viewer_gh.php?code=includes/learnopengl/camera.h
#include <camera.h>
#include <iostream>
void InitGLFW();
bool CreateWindow();
bool InitGLAD();// 窗口大小改变时调用
void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void mouse_callback(GLFWwindow *window, double xposIn, double yposIn);
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset);
void processInput(GLFWwindow *window);
unsigned int loadTexture(const char *path);// settings 窗口宽高
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;// 相机
Camera camera(glm::vec3(0.0f, 0.0f, 6.0f));
float lastX = static_cast<float>(SCR_WIDTH) / 2.0;
float lastY = static_cast<float>(SCR_HEIGHT) / 2.0;
bool firstMouse = true;// timing
float deltaTime = 0.0f; // time between current frame and last frame
float lastFrame = 0.0f;// lighting
glm::vec3 lightPos(0.5f, 0.5f, 1.0f);GLFWwindow *window;int main()
{InitGLFW(); // 初始化GLFWbool isCreated = CreateWindow(); // 创建一个窗口对象if (!isCreated)return -1;bool isGLAD = InitGLAD(); // 初始化GLAD,传入加载系统相关opengl函数指针的函数if (!isGLAD)return -1;// 启用深度测试glEnable(GL_DEPTH_TEST);// 构建和编译着色程序Shader lightingShader("shader/P1_Basic/08_LightModel/lighting_maps.vs", "shader/P1_Basic/08_LightModel/lighting_maps.fs");Shader lightCubeShader("shader/P1_Basic/08_LightModel/light_mrt_cube.vs", "shader/P1_Basic/08_LightModel/light_mrt_cube.fs");// 设置顶点数据(和缓冲区)并配置顶点属性// 1.设置立方体顶点输入 一共需要36个顶点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};// 2.设置索引缓冲对象unsigned int VBO, cubeVAO;glGenVertexArrays(1, &cubeVAO);glGenBuffers(1, &VBO);glBindBuffer(GL_ARRAY_BUFFER, VBO);glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);glBindVertexArray(cubeVAO);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);// second, configure the light's VAO (VBO stays the same; the vertices are the same for the light object which is also a 3D cube)unsigned int lightCubeVAO;glGenVertexArrays(1, &lightCubeVAO);glBindVertexArray(lightCubeVAO);glBindBuffer(GL_ARRAY_BUFFER, VBO);// note that we update the lamp's position attribute's stride to reflect the updated buffer dataglVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);glEnableVertexAttribArray(0);// 加载纹理https://learnopengl-cn.github.io/img/02/04/container2.pngunsigned int diffuseMap = loadTexture("image/04_Textures/container2.png");// shader configuration// --------------------lightingShader.use();lightingShader.setInt("material.diffuse", 0);// 循环渲染while (!glfwWindowShouldClose(window)){// 计算帧间隔时间float currentFrame = static_cast<float>(glfwGetTime());deltaTime = currentFrame - lastFrame;lastFrame = currentFrame;// 输入processInput(window);// 渲染// 清除颜色缓冲glClearColor(0.1f, 0.1f, 0.1f, 1.0f);// 清除深度缓冲glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);// be sure to activate shader when setting uniforms/drawing objectslightingShader.use();lightingShader.setVec3("light.position", lightPos);lightingShader.setVec3("viewPos", camera.Position);// light propertieslightingShader.setVec3("light.ambient", 0.2f, 0.2f, 0.2f);lightingShader.setVec3("light.diffuse", 0.5f, 0.5f, 0.5f);lightingShader.setVec3("light.specular", 1.0f, 1.0f, 1.0f);// material propertieslightingShader.setVec3("material.specular", 0.5f, 0.5f, 0.5f);lightingShader.setFloat("material.shininess", 64.0f);// view/projection transformationsglm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);glm::mat4 view = camera.GetViewMatrix();lightingShader.setMat4("projection", projection);lightingShader.setMat4("view", view);// world transformationglm::mat4 model = glm::mat4(1.0f);lightingShader.setMat4("model", model);// bind diffuse mapglActiveTexture(GL_TEXTURE0);glBindTexture(GL_TEXTURE_2D, diffuseMap);// render the cubeglBindVertexArray(cubeVAO);glDrawArrays(GL_TRIANGLES, 0, 36);// also draw the lamp objectlightCubeShader.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(0.4f)); // a smaller cubelightCubeShader.setMat4("model", model);glBindVertexArray(lightCubeVAO);glDrawArrays(GL_TRIANGLES, 0, 36);// 检查并调用事件,交换缓冲glfwSwapBuffers(window);glfwPollEvents();}// 可选:一旦资源超出其用途,就取消分配所有资源:glDeleteVertexArrays(1, &cubeVAO);glDeleteVertexArrays(1, &lightCubeVAO);glDeleteBuffers(1, &VBO);// 释放/删除之前的分配的所有资源glfwTerminate();return 0;
}void InitGLFW()
{// 初始化GLFWglfwInit();// 配置GLFW 第一个参数代表选项的名称,我们可以从很多以GLFW_开头的枚举值中选择;// 第二个参数接受一个整型,用来设置这个选项的值。glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);// glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
}
bool CreateWindow()
{// 创建一个窗口对象window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);if (window == NULL){std::cout << "Failed to create GLFW window" << std::endl;// 创建失败,终止程序glfwTerminate();return false;}// 将我们窗口的上下文设置为当前线程的主上下文glfwMakeContextCurrent(window);// 设置窗口大小改变时的回调函数glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);// 设置鼠标移动回调函数glfwSetCursorPosCallback(window, mouse_callback);// 设置滚轮滚动回调函数glfwSetScrollCallback(window, scroll_callback);// 隐藏并捕捉鼠标// glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);return true;
}
bool InitGLAD()
{// 初始化GLAD,传入加载系统相关opengl函数指针的函数if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){std::cout << "Failed to initialize GLAD" << std::endl;// 初始化失败,终止程序return false;}return true;
}// 窗口大小改变时调用
void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{// 设置窗口的维度glViewport(0, 0, width, height);
}// 输入
void processInput(GLFWwindow *window)
{// 当用户按下esc键,我们设置window窗口的windowShouldClose属性为true// 关闭应用程序if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)glfwSetWindowShouldClose(window, true);if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)camera.ProcessKeyboard(FORWARD, deltaTime);if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)camera.ProcessKeyboard(BACKWARD, deltaTime);if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)camera.ProcessKeyboard(LEFT, deltaTime);if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)camera.ProcessKeyboard(RIGHT, deltaTime);
}// 鼠标移动回调函数
void mouse_callback(GLFWwindow *window, double xposIn, double yposIn)
{// 长按T键,鼠标才能控制相机if (glfwGetKey(window, GLFW_KEY_1) != GLFW_PRESS)return;float xpos = static_cast<float>(xposIn);float ypos = static_cast<float>(yposIn);if (firstMouse){lastX = xpos;lastY = ypos;firstMouse = false;}float xoffset = xpos - lastX;float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to toplastX = xpos;lastY = ypos;camera.ProcessMouseMovement(xoffset, yoffset);
}// 鼠标滚轮滚动回调函数
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset)
{camera.ProcessMouseScroll(static_cast<float>(yoffset));
}
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;
}
运行效果 :
高光反射贴图
我们同样可以使用一个专门用于镜面高光的纹理贴图。这也就意味着我们需要生成一个黑白的(如果你想得话也可以是彩色的)纹理,来定义物体每部分的镜面光强度。
镜面高光的强度可以通过图像每个像素的亮度
来获取。镜面光贴图上的每个像素都可以由一个颜色向量来表示,比如说黑色代表颜色向量vec3(0.0),灰色代表颜色向量vec3(0.5)。
在片段着色器中,我们接下来会取样对应的颜色值并将它乘以光源的镜面强度。一个像素越「白」,乘积就会越大,物体的镜面光分量就会越亮。
从实际角度来说,木头其实也有镜面高光,尽管它的反光度(Shininess)很小(更多的光被散射),影响也比较小,但是为了教学目的,我们可以假设木头不会对镜面光有任何反应。
采样镜面光贴图
创建片段着色器的材质属性,让其接受一个sampler2D而不是vec3作为镜面光分量:
struct Material {sampler2D diffuse;sampler2D specular;float shininess;
};
然后,通过采样镜面光贴图,来获取片段所对应的镜面光强度:
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));
FragColor = vec4(ambient + diffuse + specular, 1.0);
脚本实现
我们只创建片元着色器,顶点着色器和上面漫反射一样的,源码也类似
源码
...// 加载纹理// https://learnopengl-cn.github.io/img/02/04/container2.pngunsigned int diffuseMap = loadTexture("image/04_Textures/container2.png");// https://learnopengl-cn.github.io/img/02/04/container2_specular.pngunsigned int specularMap = loadTexture("image/04_Textures/container2_specular.png");...// 循环渲染while (!glfwWindowShouldClose(window)){...// bind diffuse mapglActiveTexture(GL_TEXTURE0);glBindTexture(GL_TEXTURE_2D, diffuseMap);// bind specular mapglActiveTexture(GL_TEXTURE1);glBindTexture(GL_TEXTURE_2D, specularMap);...
}
lighting_specular_maps.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()
{// ambientvec3 ambient = light.ambient * texture(material.diffuse, TexCoords).rgb;// diffuse 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; // specularvec3 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);
}
运行效果: