OpenGL基礎22：貼圖

在 OpenGL基礎13：第一個正方體中給正方體加了箱子的紋理，但是在後面介紹光照的時候又把紋理屬性給丟了，現在嘗試在有紋理的基礎之上增加光照

一、漫反射貼圖

先把之前的紋理加回去

頂點着色器和主代碼的處理和之前 OpenGL基礎9：紋理紋理這一章一樣，而對於片段着色器，需要進行稍加修改

在 OpenGL基礎21：材質這一章裏，給予了物體材質屬性，包括：

ambient：定義了在環境光照下這個物體反射的是什麼顏色，通常是和物體顏色相同的顏色
diffuse：定義了在漫反射光照下物體的顏色，通常是和物體顏色相同的顏色
specular：~~設置的是物體受到的鏡面光照影響的顏色，或者是反射一個物體特定的鏡面高光顏色~~（暫時不考慮）
shininess：~~反光度，值越高，反射光的能力越強，散射得越少，高光點越小~~（暫時不考慮）

但是，一個物體自身作爲一個整體爲其擁有一個材質其實是有問題的，例如一輛汽車，輪胎和車窗的材質明顯不同，也就是說，對於物體的不同部分，可能會擁有不同的 ambient 和 diffuse 屬性

因此，這就需要通過某種方式對每個原始像素獨立設置diffuse顏色，這其實就是之前的一直在用的紋理，只不過在這中場景和需求下，我們叫它貼圖

用一張圖片覆蓋住物體，以便我們爲每個原始像素索引獨立顏色值。在光照場景中，通過紋理來呈現一個物體的diffuse顏色，這個做法被稱做漫反射貼圖(Diffuse texture)

這樣的話，在片段着色器中，原先的 ambient 和 diffuse 屬性就要用 diffuse 貼圖替代（之所以這兩個屬性都用 diffuse 是因爲大部分情況下，這兩者的值是等同的），如下：

#version 330 core
struct Material
{
    sampler2D diffuse;      //貼圖
    vec3 specular;          //鏡面光色
    float shininess;        //反光度
};
struct Light
{
    vec3 position;
    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};
uniform Material material;
uniform Light light;
out vec4 color;
uniform vec3 viewPos;
in vec2 texIn;
in vec3 fragPosIn;
in vec3 normalIn;
void main()
{
    //環境光
    vec3 ambient = light.ambient * vec3(texture(material.diffuse, texIn));

    //漫反射光
    vec3 norm = normalize(normalIn);
    vec3 lightDir = normalize(light.position - fragPosIn);
    float diff = max(dot(norm, lightDir), 0.0f);
    vec3 diffuse = light.diffuse * (diff * vec3(texture(material.diffuse, texIn)));

    //鏡面光
    vec3 viewDir = normalize(viewPos - fragPosIn);
    vec3 reflectDir = reflect(-lightDir, norm);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * (spec * material.specular);

    //混合
    vec3 result = ambient + diffuse + specular;
    color = vec4(result, 1.0f);
}

好了，效果有了！

如果仔細從各個角度看，會發現一塊木箱子居然還會有鏡面高光，這不科學，這時可以把 specular 設置爲 vec(0.0) 來修正

二、鏡面貼圖採樣

上面的箱子還是非常容易的，因爲它有一個特點：每個部分都擁有幾乎一致的 diffuse 屬性，並且 specular 屬性都爲 vec(0.0)，那麼問題來了，假設這個時候我們想要給箱子加一個金屬邊框要怎麼處理？要知道金屬擁有較高的反射度，和橡木材質正好相反，如果說只用單獨的一個帶金屬邊框的木箱紋理，那肯定也是有問題的，所以這個時候就需要2張紋理貼圖：一張爲帶金屬邊框的橡木紋理，一張爲單純金屬邊框紋理

如下，一個 specular 高光的亮度可以通過圖片中每個紋理的亮度來獲得，可以使用這兩張紋理作爲漫反射貼圖和鏡面貼圖（來源：https://learnopengl.com/#!Lighting/Lighting-maps）

specular 貼圖的每個像素可以顯示爲一個顏色向量，可以看出，這張紋理中間是一片黑，這也意味着中間部分是露出來的木頭材質，在此 specular 屬性即對應像素顏色屬性正是 vec(0.0)

使用Photoshop或Gimp之類的工具，通過將圖片進行裁剪，將某部分調整成黑白圖樣，並調整亮度/對比度的做法，可以非常容易將一個diffuse紋理貼圖處理爲specular貼圖，這樣的貼圖最好爲黑白

有了上面的經驗，就知道怎麼修改代碼邏輯了：

#version 330 core
struct Material
{
    sampler2D diffuse;      //貼圖
    sampler2D specular;     //鏡面貼圖
    float shininess;        //反光度
};
struct Light
{
    vec3 position;
    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};
uniform Material material;
uniform Light light;
out vec4 color;
uniform vec3 viewPos;
in vec2 texIn;
in vec3 fragPosIn;
in vec3 normalIn;
void main()
{
    //環境光
    vec3 ambient = light.ambient * vec3(texture(material.diffuse, texIn));

    //漫反射光
    vec3 norm = normalize(normalIn);
    vec3 lightDir = normalize(light.position - fragPosIn);
    float diff = max(dot(norm, lightDir), 0.0f);
    vec3 diffuse = light.diffuse * (diff * vec3(texture(material.diffuse, texIn)));

    //鏡面光
    vec3 viewDir = normalize(viewPos - fragPosIn);
    vec3 reflectDir = reflect(-lightDir, norm);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * (spec * vec3(texture(material.specular, texIn)));

    //混合
    vec3 result = ambient + diffuse + specular;
    color = vec4(result, 1.0f);
}

效果如下：

三、放射光貼圖

上面使用了漫反射貼圖和鏡面貼圖，物體已經有點真實的感覺了，後面還有法線貼圖和反射貼圖，可以給物體更完美的細節，只是這裏就暫時不講了

這裏可以再提一個非常簡單的貼圖：放射光貼圖，先上整篇文章的完整代碼和效果，非常容易

#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texture;
out vec2 texIn;
out vec3 normalIn;
out vec3 fragPosIn;
uniform mat4 model;             //模型矩陣
uniform mat4 view;              //觀察矩陣
uniform mat4 projection;        //投影矩陣
void main()
{
    gl_Position = projection * view * model * vec4(position, 1.0);
    texIn = vec2(texture.x, 1.0f - texture.y);
    fragPosIn = vec3(model * vec4(position, 1.0f));
    normalIn = mat3(transpose(inverse(model))) * normal;
}

//////////////////////////////////////////////////////////////////////////

#version 330 core
struct Material
{
    sampler2D diffuse;      //貼圖
    sampler2D specular;     //鏡面貼圖
    sampler2D emission;     //放射貼圖
    float shininess;        //反光度
};
struct Light
{
    vec3 position;
    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};
uniform Material material;
uniform Light light;
out vec4 color;
uniform vec3 viewPos;
in vec2 texIn;
in vec3 fragPosIn;
in vec3 normalIn;
void main()
{
    //環境光
    vec3 ambient = light.ambient * vec3(texture(material.diffuse, texIn));

    //漫反射光
    vec3 norm = normalize(normalIn);
    vec3 lightDir = normalize(light.position - fragPosIn);
    float diff = max(dot(norm, lightDir), 0.0f);
    vec3 diffuse = light.diffuse * (diff * vec3(texture(material.diffuse, texIn)));

    //鏡面光
    vec3 viewDir = normalize(viewPos - fragPosIn);
    vec3 reflectDir = reflect(-lightDir, norm);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * (spec * vec3(texture(material.specular, texIn)));

    //放射光貼圖
    vec3 emission = vec3(texture(material.emission, texIn));

    //混合
    vec3 result = ambient + diffuse + specular + emission;
    color = vec4(result, 1.0f);
}

main.cpp：

#include<iostream>
#include<opengl/glew.h>
#define GLEW_STATIC
#include<GLFW/glfw3.h>
#include"Camera.h"
#include<glm/glm.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<glm/gtc/type_ptr.hpp>
#include"Shader.h"
#include<opengl/freeglut.h>
#include<SOIL.h>

bool keys[1024];
Camera camera;
GLfloat lastX, lastY;
bool firstMouse = true;
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void cameraMove();
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);
const GLuint WIDTH = 800, HEIGHT = 600;

int main()
{
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

    GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
    glfwMakeContextCurrent(window);
    glfwSetKeyCallback(window, key_callback);
    glfwSetCursorPosCallback(window, mouse_callback);
    glfwSetScrollCallback(window, scroll_callback);

    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
    glewExperimental = GL_TRUE;
    glewInit();

    int width, height;
    glfwGetFramebufferSize(window, &width, &height);
    glViewport(0, 0, width, height);

    Shader shaderObj("ObjVShader.txt", "ObjFShader.txt");
    Shader shaderLight("LightVShader.txt", "LightFShader.txt");

    GLfloat 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
    };
    GLuint VBO, VAO, textureA, textureB, textureC;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);

    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
    glEnableVertexAttribArray(2);

    int picWidth, picHeight;
    glGenTextures(1, &textureA);
    glBindTexture(GL_TEXTURE_2D, textureA);
    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);
    unsigned char* image = SOIL_load_image("Texture/wood2.jpg", &picWidth, &picHeight, 0, SOIL_LOAD_RGB);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, picWidth, picHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
    glGenerateMipmap(GL_TEXTURE_2D);
    SOIL_free_image_data(image);

    glGenTextures(1, &textureB);
    glBindTexture(GL_TEXTURE_2D, textureB);
    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_NEAREST_MIPMAP_NEAREST);
    image = SOIL_load_image("Texture/specular.jpg", &picWidth, &picHeight, 0, SOIL_LOAD_RGB);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, picWidth, picHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
    glGenerateMipmap(GL_TEXTURE_2D);
    SOIL_free_image_data(image);

    glGenTextures(1, &textureC);
    glBindTexture(GL_TEXTURE_2D, textureC);
    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_NEAREST_MIPMAP_NEAREST);
    image = SOIL_load_image("Texture/cloudImg.jpg", &picWidth, &picHeight, 0, SOIL_LOAD_RGB);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, picWidth, picHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
    glGenerateMipmap(GL_TEXTURE_2D);
    SOIL_free_image_data(image);
    glBindTexture(GL_TEXTURE_2D, 0);

    shaderObj.Use();
    glUniform1i(glGetUniformLocation(shaderObj.Program, "material.diffuse"), 0);
    glUniform1i(glGetUniformLocation(shaderObj.Program, "material.specular"), 1);
    glUniform1i(glGetUniformLocation(shaderObj.Program, "material.emission"), 2);

    GLuint lightVAO;
    glGenVertexArrays(1, &lightVAO);
    glBindVertexArray(lightVAO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
    //VBO數據已經綁定且我們就用之前的頂點數據，所以無需再管理VBO
    glEnableVertexAttribArray(0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    glEnable(GL_DEPTH_TEST);
    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        glClear(GL_DEPTH_BUFFER_BIT);
        cameraMove();

        shaderLight.Use();
        lightPos.x = 1.0f + sin(glfwGetTime()) * 2.0f;
        lightPos.y = sin(glfwGetTime() / 2.0f) * 1.0f;
        glm::mat4 view = camera.GetViewMatrix();
        glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (GLfloat)WIDTH / (GLfloat)HEIGHT, 0.1f, 100.0f);
        glm::mat4 model = glm::translate(glm::mat4(1.0f), lightPos);
        model = glm::scale(model, glm::vec3(0.2f));
        GLint modelLoc = glGetUniformLocation(shaderLight.Program, "model");
        GLint viewLoc = glGetUniformLocation(shaderLight.Program, "view");
        GLint projLoc = glGetUniformLocation(shaderLight.Program, "projection");
        glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
        glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));

        glBindVertexArray(lightVAO);
        glDrawArrays(GL_TRIANGLES, 0, 36);

        shaderObj.Use();
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, textureA);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, textureB);
        glActiveTexture(GL_TEXTURE2);
        glBindTexture(GL_TEXTURE_2D, textureC);
        GLint matSpecularLoc = glGetUniformLocation(shaderObj.Program, "material.specular");
        GLint matShineLoc = glGetUniformLocation(shaderObj.Program, "material.shininess");
        glUniform3f(matSpecularLoc, 0.0f, 0.0f, 0.0f);
        glUniform1f(matShineLoc, 32.0f);

        GLint lightPosLoc = glGetUniformLocation(shaderObj.Program, "light.position");
        GLint lightAmbientLoc = glGetUniformLocation(shaderObj.Program, "light.ambient");
        GLint lightDiffuseLoc = glGetUniformLocation(shaderObj.Program, "light.diffuse");
        GLint lightSpecularLoc = glGetUniformLocation(shaderObj.Program, "light.specular");
        glUniform3f(lightAmbientLoc, 0.2f, 0.2f, 0.2f);
        glUniform3f(lightDiffuseLoc, 1.0f, 1.0f, 1.0f);
        glUniform3f(lightSpecularLoc, 1.0f, 1.0f, 1.0f);
        glUniform3f(lightPosLoc, lightPos.x, lightPos.y, lightPos.z);

        GLint viewPosLoc = glGetUniformLocation(shaderObj.Program, "viewPos");
        glUniform3f(viewPosLoc, camera.Position.x, camera.Position.y, camera.Position.z);
        model = glm::mat4(1.0f);
        model = glm::rotate(model, glm::radians(57.0f), glm::vec3(-0.5f, 1.0f, 0.0f));
        modelLoc = glGetUniformLocation(shaderObj.Program, "model");
        viewLoc = glGetUniformLocation(shaderObj.Program, "view");
        projLoc = glGetUniformLocation(shaderObj.Program, "projection");
        glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
        glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));

        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 36);

        glBindVertexArray(0);
        glfwSwapBuffers(window);
    }
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glfwTerminate();
    return 0;
}

GLfloat deltaTime = 0.0f;
GLfloat lastFrame = 0.0f;
void cameraMove()
{
    GLfloat currentFrame = glfwGetTime();
    deltaTime = currentFrame - lastFrame;
    lastFrame = currentFrame;

    GLfloat cameraSpeed = 1.0f * deltaTime;
    if (keys[GLFW_KEY_W])
        camera.ProcessKeyboard(Camera_Movement(FORWARD), deltaTime);
    if (keys[GLFW_KEY_S])
        camera.ProcessKeyboard(Camera_Movement(BACKWARD), deltaTime);
    if (keys[GLFW_KEY_A])
        camera.ProcessKeyboard(Camera_Movement(LEFT), deltaTime);
    if (keys[GLFW_KEY_D])
        camera.ProcessKeyboard(Camera_Movement(RIGHT), deltaTime);
}

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
    if (action == GLFW_PRESS)           //如果當前是按下操作
        keys[key] = true;
    else if (action == GLFW_RELEASE)            //鬆開鍵盤
        keys[key] = false;
}

void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
    camera.ProcessMouseScroll(yoffset);
}

void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
    if (firstMouse)
    {
        lastX = xpos;
        lastY = ypos;
        firstMouse = false;
    }
    GLfloat xoffset = xpos - lastX;
    GLfloat yoffset = lastY - ypos;
    lastX = xpos;
    lastY = ypos;
    
    GLfloat sensitivity = 0.05;
    xoffset *= sensitivity;
    yoffset *= sensitivity;
    
    camera.ProcessMouseMovement(xoffset, yoffset);
}

可以看到，箱子的每個面上都有被貼上了一塊無視光照的“雲彩”，這就是放射光貼圖，顧名思義，它往往是用來顯示物體自身發光(Emit)時可能產生的顏色，例如遊戲中寶箱上發光的按鈕，樓梯間緊急出口牌子亮的綠光等等

OpenGL基礎22：貼圖

一、漫反射貼圖

二、鏡面貼圖採樣

三、放射光貼圖

如何使用 JS 判斷用戶是否處於活躍狀態

通過HPA+CronHPA組合應對業務複雜彈性伸縮場景

❤️‍🔥 Solon Cloud Event 新的事務特性與應用

OpenGL基礎28：模型

LuaForUnity9：uLua的一個簡單實例

LuaForUnity7：Lua“類與對象”

C#基礎14：泛型

OpenGL基礎27：網格

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

linux以太網驅動總結