• OpenGL_Learn12（光照）

     续OpenGL_Learn11（光照）-CSDN博客

    1. 镜面高光

    和漫反射光照一样，镜面光照也决定于光的方向向量和物体的法向量，但是它也决定于观察方向，例如玩家是从什么方向看向这个片段的。镜面光照决定于表面的反射特性。

    我们通过根据法向量翻折入射光的方向来计算反射向量（对称就是R那条线）。然后我们计算反射向量与观察方向的角度差，它们之间夹角越小，镜面光的作用就越大。由此产生的效果就是，我们看向在入射光在表面的反射方向时，会看到一点高光。

    只需要修改

    cube.vs

    增加翻折后的法向量

    1. #version 330 core
    2. layout (location = 0) in vec3 aPos;
    3. layout (location =0 ) in vec3 aNormal;
    4.  
    5. out vec3 FragPos;
    6. out vec3 Normal;
    7.  
    8. uniform mat4 model;
    9. uniform mat4 view;
    10. uniform mat4 projection;
    11.  
    12. void main()
    13. {
    14.     FragPos=vec3(model*vec4(aPos,1.0));
    15.     Normal=mat3(transpose(inverse(model)))*aNormal;
    16.     gl_Position = projection * view  * vec4(FragPos, 1.0);
    17. }

    cube.fs

     增加一个高光因子

    1. #version 330 core
    2. out vec4 FragColor;
    3.  
    4. in vec3 Normal;
    5. in vec3 FragPos;
    6.  
    7. uniform vec3 objectColor;
    8. uniform vec3 lightColor;
    9. uniform vec3 lightPos;
    10. uniform vec3 viewPos;
    11.  
    12. void main()
    13. {
    14.     //ambient
    15.     float ambientStrength=0.1;
    16.     vec3 ambient=ambientStrength*lightColor;
    17.  
    18.     //diffuse
    19.     vec3 norm=normalize(Normal);
    20.     vec3 lightDir=normalize(lightPos-FragPos);//光的方向向量是光源位置向量与片段位置向量之间的向量差。
    21.     //对norm和lightDir向量进行点乘，计算光源对当前片段实际的漫反射影响
    22.     //两个向量之间的角度越大，漫反射分量就会越小，点乘的几何意义也如此
    23.     float diff=max(dot(norm,lightDir),0.0);
    24.     vec3 diffuse=diff*lightColor;
    25.  
    26.     //specular
    27.     float specularStrength=0.5;//高光强度
    28.     //漫反射是光源指向片段位置。现在这个是摄像机指向片段位置
    29.     vec3 viewDir=normalize(viewPos-FragPos);
    30.     vec3 reflectDir=reflect(-lightDir,norm);//reflect第一个参数就是要片段指向摄像机位置
    31.     float spec=pow(max(dot(viewDir,reflectDir),0.0),32);
    32.     vec3 specular=specularStrength*spec*lightColor;
    33.  
    34.     vec3 result=(ambient+diffuse+specular)*objectColor;
    35.     FragColor = vec4(result, 1.0);
    36. }

     main.cpp

    1. #include 
    2. #include 
    3.  
    4. #include 
    5. #include "stb_image.h"
    6. #include 
    7. #include "shader.h"
    8. #include "camera.h"
    9.  
    10. #include 
    11. #include 
    12. #include 
    13.  
    14. void framebuffer_size_callback(GLFWwindow* window, int width, int height);
    15. void processInput(GLFWwindow* window);
    16. void mouse_callback(GLFWwindow* window, double xpos, double ypos);
    17. void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
    18.  
    19. // settings
    20. const unsigned int SCR_WIDTH = 1800;
    21. const unsigned int SCR_HEIGHT = 1200;
    22.  
    23.  
    24. //camera
    25. Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
    26. float lastX = SCR_WIDTH / 2.0f;
    27. float lastY = SCR_HEIGHT / 2.0f;
    28. bool firstMouse = true;
    29.  
    30. //timing
    31. float deltaTime = 0.0f;//不同配置绘制速度不同，所以需要这个属性
    32. float lastFrame = 0.0f;
    33.  
    34. //lighting
    35. glm::vec3 lightPos(1.2f, 1.0f, 2.0f);
    36.  
    37. int main() {
    38. 	//glfw:initialize and configure
    39. 	//=============================
    40. 	glfwInit();
    41. 	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    42. 	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    43. 	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    44.  
    45. #ifdef __APPLE__
    46. 	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
    47. #endif
    48.  
    49. 	//glfw window creation
    50. 	//=============================
    51. 	GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "Learn", NULL, NULL);
    52. 	if (window == NULL) {
    53. 		std::cout << "Failed to create GLFW window" << std::endl;
    54. 		glfwTerminate();
    55. 		return -1;
    56. 	}
    57.  
    58. 	glfwMakeContextCurrent(window);
    59. 	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    60. 	glfwSetCursorPosCallback(window, mouse_callback);
    61. 	glfwSetScrollCallback(window, scroll_callback);
    62.  
    63. 	//tell GLFW to capture our mouse
    64. 	glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
    65.  
    66. 	//glad::load all OPenGL function pointers
    67. 	//=============================
    68. 	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
    69. 		std::cout << "Failed to initialize GLAD" << std::endl;
    70. 		return -1;
    71. 	}
    72.  
    73. 	//configure gloabl opengl state
    74. 	//=============================
    75. 	glEnable(GL_DEPTH_TEST);
    76.  
    77. 	//build and compile our shader zprogram
    78. 	//=============================
    79. 	Shader lightingShader("./cube.vs", "./cube.fs");
    80.     Shader lightingCubeShader("./light_cube.vs", "./light_cube.fs");
    81. 	//set up vertex data 
    82.  
    83.     float vertices[] = {
    84.     -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    85.      0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    86.      0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    87.      0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    88.     -0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    89.     -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
    90.  
    91.     -0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
    92.      0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
    93.      0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
    94.      0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
    95.     -0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
    96.     -0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
    97.  
    98.     -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
    99.     -0.5f,  0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
    100.     -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
    101.     -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
    102.     -0.5f, -0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
    103.     -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
    104.  
    105.      0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
    106.      0.5f,  0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
    107.      0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
    108.      0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
    109.      0.5f, -0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
    110.      0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
    111.  
    112.     -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
    113.      0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
    114.      0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
    115.      0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
    116.     -0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
    117.     -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
    118.  
    119.     -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
    120.      0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
    121.      0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
    122.      0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
    123.     -0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
    124.     -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f
    125.     };
    126.  
    127.     //第一个
    128.     unsigned int VBO, cubeVAO;
    129.     glGenVertexArrays(1, &cubeVAO);
    130.     glGenBuffers(1, &VBO);
    131.  
    132.     glBindBuffer(GL_ARRAY_BUFFER, VBO);
    133.     glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    134.  
    135.     glBindVertexArray(cubeVAO);
    136.  
    137.     //position attribute
    138.     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    139.     glEnableVertexAttribArray(0);
    140.     //normal attribute
    141.     glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    142.     glEnableVertexAttribArray(1);
    143.  
    144.     
    145.     //第二个
    146.     unsigned int lightCubeVAO;
    147.     glGenVertexArrays(1, &lightCubeVAO);
    148.     glBindVertexArray(lightCubeVAO);
    149.  
    150.     glBindBuffer(GL_ARRAY_BUFFER, VBO);
    151.  
    152.     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    153.     glEnableVertexAttribArray(0);
    154.  
    155.  
    156.  
    157.     // render loop
    158.     // -----------
    159.     while (!glfwWindowShouldClose(window))
    160.     {
    161.         // per-frame time logic
    162.         // --------------------
    163.         float currentFrame = static_cast<float>(glfwGetTime());
    164.         deltaTime = currentFrame - lastFrame;
    165.         lastFrame = currentFrame;
    166.  
    167.         // input
    168.         // -----
    169.         processInput(window);
    170.  
    171.         // render
    172.         // ------
    173.         glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
    174.         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    175.  
    176.         // be sure to activate shader when setting uniforms/drawing objects
    177.         lightingShader.use();
    178.         lightingShader.setVec3("objectColor", 1.0f, 0.5f, 0.31f);
    179.         lightingShader.setVec3("lightColor", 1.0f, 1.0f, 1.0f);
    180.         lightingShader.setVec3("lightPos", lightPos);
    181.         lightingShader.setVec3("viewPos", camera.Position);
    182.  
    183.         // view/projection transformations
    184.         glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
    185.         glm::mat4 view = camera.GetViewMatrix();
    186.         lightingShader.setMat4("projection", projection);
    187.         lightingShader.setMat4("view", view);
    188.  
    189.         // world transformation
    190.         glm::mat4 model = glm::mat4(1.0f);
    191.         lightingShader.setMat4("model", model);
    192.  
    193.         // render the cube
    194.         glBindVertexArray(cubeVAO);
    195.         glDrawArrays(GL_TRIANGLES, 0, 36);
    196.  
    197.  
    198.         // also draw the lamp object
    199.         lightingCubeShader.use();
    200.         lightingCubeShader.setMat4("projection", projection);
    201.         lightingCubeShader.setMat4("view", view);
    202.         model = glm::mat4(1.0f);
    203.         model = glm::translate(model, lightPos);
    204.         model = glm::scale(model, glm::vec3(0.2f)); // a smaller cube
    205.         lightingCubeShader.setMat4("model", model);
    206.  
    207.         glBindVertexArray(lightCubeVAO);
    208.         glDrawArrays(GL_TRIANGLES, 0, 36);
    209.  
    210.  
    211.         // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
    212.         // -------------------------------------------------------------------------------
    213.         glfwSwapBuffers(window);
    214.         glfwPollEvents();
    215.     }
    216.  
    217.     glDeleteVertexArrays(1, &cubeVAO);
    218.     glDeleteVertexArrays(1, &lightCubeVAO);
    219.     glDeleteBuffers(1, &VBO);
    220.  
    221.     glfwTerminate();
    222.     return 0;
    223.  
    224. }
    225. void processInput(GLFWwindow* window)
    226. {
    227.     if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    228.         glfwSetWindowShouldClose(window, true);
    229.  
    230.     if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
    231.         camera.ProcessKeyboard(FORWARD, deltaTime);
    232.     if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
    233.         camera.ProcessKeyboard(BACKWARD, deltaTime);
    234.     if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    235.         camera.ProcessKeyboard(LEFT, deltaTime);
    236.     if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
    237.         camera.ProcessKeyboard(RIGHT, deltaTime);
    238. }
    239.  
    240. void framebuffer_size_callback(GLFWwindow* window, int width, int height)
    241. {
    242.     // make sure the viewport matches the new window dimensions; note that width and 
    243.     // height will be significantly larger than specified on retina displays.
    244.     glViewport(0, 0, width, height);
    245. }
    246. // glfw: whenever the mouse moves, this callback is called
    247. // -------------------------------------------------------
    248. void mouse_callback(GLFWwindow* window, double xposIn, double yposIn)
    249. {
    250.     float xpos = static_cast<float>(xposIn);
    251.     float ypos = static_cast<float>(yposIn);
    252.  
    253.     if (firstMouse)
    254.     {
    255.         lastX = xpos;
    256.         lastY = ypos;
    257.         firstMouse = false;
    258.     }
    259.  
    260.     float xoffset = xpos - lastX;
    261.     float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
    262.  
    263.     lastX = xpos;
    264.     lastY = ypos;
    265.  
    266.     camera.ProcessMouseMovement(xoffset, yoffset);
    267. }
    268.  
    269. // glfw: whenever the mouse scroll wheel scrolls, this callback is called
    270. // ----------------------------------------------------------------------
    271. void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
    272. {
    273.     camera.ProcessMouseScroll(static_cast<float>(yoffset));
    274. }

    2. 动态光源位置

    目前，我们的光源是静止的，尝试使用sin或cos函数让光源在场景中来回移动。观察光照随时间的改变能让你更容易理解冯氏光照模型。

    1.         //动态修改 光源位置
    2.         lightPos.x = 1.0f + sin(glfwGetTime()) * 2.0f;
    3.         lightPos.y = sin(glfwGetTime() / 2.0f) * 1.0f;
    4.         lightingShader.setVec3("lightPos", lightPos);

     

     基础光照 - LearnOpenGL CN (learnopengl-cn.github.io)

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  • 原文地址：https://blog.csdn.net/qq_59068750/article/details/134431482