LearnOpenGL 模型加载—模型(二 绘制模型)
2024-05-12 18:44:20
文章目录
- 写在前面
- 和箱子模型告别
- 坑点
- 回到主题
写在前面
原文链接。原文应该是github上的一个项目，本文主要用来记录一些知识点和自己遇到的问题。
和箱子模型告别
所以，让我们导入一个由真正的艺术家所创造的模型，替代我这个天才的作品（你要承认，这些箱子可能是你看过的最漂亮的立方体了），测试一下我们的实现吧。由于我不想让我占太多的功劳，我会偶尔让别的艺术家也加入我们，这次我们将会加载Crytek的游戏孤岛危机(Crysis)中的原版纳米装(Nanosuit)。这个模型被输出为一个.obj文件以及一个.mtl文件，.mtl文件包含了模型的漫反射、镜面光和法线贴图（这个会在后面学习到），你可以在这里下载到（稍微修改之后的）模型，注意所有的纹理和模型文件应该位于同一个目录下，以供加载纹理。
现在在代码中，声明一个Model对象，将模型的文件位置传入。接下来模型应该会自动加载并（如果没有错误的话）在渲染循环中使用它的Draw函数来绘制物体，这样就可以了。不再需要缓冲分配、属性指针和渲染指令，只需要一行代码就可以了（真爽！）。接下来如果你创建一系列着色器，其中片段着色器仅仅输出物体的漫反射纹理颜色，最终的结果看上去会是这样的：
你可以在这里找到完整的源码。
这里有一个很坑的问题，可能让你得不到正确结果……事实上我也费了很多时间来debug，下面来说一下。
坑点
主要是由0号纹理单元引起的……
原文这里的代码其实是有点问题的，我们看一下他这里给出的着色器代码：
#version 330 core
out vec4 FragColor;in vec2 TexCoords;uniform sampler2D texture_diffuse1;void main()
{ FragColor = texture(texture_diffuse1, TexCoords);
}
再看我们在Mesh对象的Draw方法中设置的采样器名称：
很明显这里是对不上的，那么为什么我们还能看到模型呢？是因为0号纹理单元默认是一直激活的，在GLSL中的纹理采样器默认都会绑定到0号纹理单元，而我们在代码中恰好又绑定了纹理对象到这个纹理单元，所以能看到模型。那么我们可以改一下这个函数，让其激活并设置非零号纹理单元，就可以解决问题了——实际上并不能，你可以看一下texture对象的构造函数，其内调用了glBindTexture函数，也就是说只要使用了纹理对象，0号纹理单元上就一定绑定了某个纹理对象，那么在GLSL中进行采样时就一定要小心，采样的结果可能并不是黑色！出于这个原因我决定修改命名规则，我们使用sampler2D数组，同时传递两个整数给gpu，告诉它我们使用了多少个漫反射贴图和镜面光贴图。
第二个坑点是图片y轴的翻转问题。我们在纹理章节已经学过了：OpenGL要求y轴0.0坐标是在图片的底部的，但是图片的y轴0.0坐标通常在顶部。那么我们利用这个函数翻转图片的y轴：
但是还记得我们在导入obj文件的时候设置了什么吗？
aiProcess_FlipUVs将在处理的时候翻转y轴的纹理坐标。如果你感觉贴图很奇怪的话，可能就是这里的问题，两个地方都翻转了等于没有翻转。
回到主题
修改后的代码如下：
mesh:mesh:mesh:
#pragma once
#ifndef MESH_H
#define MESH_H#include <glad/glad.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include "shader.h"
#include <vector>
#include "texture.h"
#include <string>
#include <iostream>
using std::vector;
using std::string;
using std::cout;
using std::max;struct Vertex
{// 位置 法向量 纹理坐标glm::vec3 Position;glm::vec3 Normal;glm::vec2 TexCoords;
};class Mesh
{public:/* 网格数据 */vector<Vertex> vertices;vector<unsigned int> indices;vector<Texture> textures;/* 函数 */Mesh(const vector<Vertex>& vertices, const vector<unsigned int>& indices, const vector<Texture>& textures);void Draw(const Shader& shader);
private:/* 渲染数据 */unsigned int VAO, VBO, EBO;void setupMesh();
};#endif // !MESH_H#include "mesh.h"Mesh::Mesh(const vector<Vertex>& vertices, const vector<unsigned int>& indices, const vector<Texture>& textures) :vertices(vertices), indices(indices), textures(textures)
{setupMesh();
}void Mesh::setupMesh()
{// 初始化VAO VBO EBOglGenVertexArrays(1, &VAO);glGenBuffers(1, &VBO);glGenBuffers(1, &EBO);// 绑定VAOglBindVertexArray(VAO);// 绑定VBO 复制顶点数据glBindBuffer(GL_ARRAY_BUFFER, VBO);glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), &vertices[0], GL_STATIC_DRAW);// 绑定EBO 复制索引数据glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned int), &indices[0], GL_STATIC_DRAW);// 顶点位置glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)0);glEnableVertexAttribArray(0);// 顶点法线// C++内置的offsetof函数 能自动返回结构对象中 某变量距离结构体对象首地址的偏移值：glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, Normal));glEnableVertexAttribArray(1);// 顶点纹理坐标glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, TexCoords));glEnableVertexAttribArray(2);// 解绑VAOglBindVertexArray(0);
}unsigned int maxDiffuseNr = 0;
unsigned int maxSpecularNr = 0;void Mesh::Draw(const Shader& shader)
{// 当前漫反射纹理和镜面光纹理的编号unsigned int diffuseNr = 0;unsigned int specularNr = 0;for (unsigned int i = 0; i < textures.size(); i++){// 激活纹理单元 并绑定textures[i].use(i);// 获取纹理序号和类型string number;string type = textures[i].getName();if (type == "texture_diffuse")number = std::to_string(diffuseNr++);else if (type == "texture_specular")number = std::to_string(specularNr++);shader.setInt("material." + type + "[" + number + "]", i);}shader.setInt(string("material.") + "texture_diffuse_num", diffuseNr);shader.setInt(string("material.") + "texture_specular_num", specularNr);maxDiffuseNr = max(maxDiffuseNr, diffuseNr);maxSpecularNr = max(maxSpecularNr, specularNr);glBindVertexArray(VAO);glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);glBindVertexArray(0);// always good practice to set everything back to defaults once configured.glActiveTexture(GL_TEXTURE0);
}
model:model:model:
#pragma once
#ifndef MODEL_H
#define MODEL_H
#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>
#include "mesh.h"
#include <unordered_map>using std::unordered_map;class Model
{/* 函数 */
public:Model(const string& path){loadModel(path);}void Draw(const Shader& shader);
private:/* 模型数据 */vector<Mesh> meshes;/* 模型数据所在目录 */string directory;/* 记录已经加载过的纹理 */vector<Texture> texturesLoaded;/* 纹理文件到索引的哈希表 */unordered_map<string, unsigned int> texturesHashTable;void loadModel(const string& path);void processNode(aiNode* node, const aiScene* scene);Mesh processMesh(aiMesh* mesh, const aiScene* scene);vector<Texture> loadMaterialTextures(aiMaterial* mat, aiTextureType type, const string& typeName);
};#endif // !MODEL_H#include "model.h"
#include <iostream>
using std::cout;
using std::endl;extern unsigned int maxDiffuseNr;
extern unsigned int maxSpecularNr;
bool firstDraw = false;void Model::Draw(const Shader& shader)
{for (unsigned int i = 0; i < meshes.size(); i++)meshes[i].Draw(shader);if (!firstDraw){cout << "First Draw finish\n";cout << "Max diffuse texture number is " << maxDiffuseNr << '\n';cout << "Max specular texture number is " << maxSpecularNr << '\n';firstDraw = 1;}
}void Model::loadModel(const string& path)
{Assimp::Importer import;// 读取模型文件 第二个参数用于后期处理const aiScene* scene = import.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);// 是否读取成功if (!scene || scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode){cout << "ERROR::ASSIMP::" << import.GetErrorString() << endl;return;}// 获取文件目录directory = path.substr(0, path.find_last_of('/'));// 从场景根节点开始递归处理所有节点processNode(scene->mRootNode, scene);// 打印obj的信息cout << "Loading success!\n";cout << "This model have " << meshes.size() << " meshes\n\n";
}void Model::processNode(aiNode* node, const aiScene* scene)
{// 处理节点的所有网格for (unsigned int i = 0; i < node->mNumMeshes; i++){// 依据索引从场景对象中拿到真正的数据aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];meshes.push_back(processMesh(mesh,scene));}// 递归处理子节点for (unsigned int i = 0; i < node->mNumChildren; i++)processNode(node->mChildren[i], scene);
}Mesh Model::processMesh(aiMesh* mesh, const aiScene* scene)
{// 一个Mesh对象包括 Vertex(位置 法向量 纹理坐标) 绘制所需的索引数组 绘制所需的纹理vector<Vertex> vertices;vector<unsigned int> indices;vector<Texture> textures;// 处理顶点位置 法线 纹理坐标for (unsigned int i = 0; i < mesh->mNumVertices; i++){Vertex vertex;// 顶点位置 该数组永远存在vertex.Position = glm::vec3(mesh->mVertices[i].x, mesh->mVertices[i].y, mesh->mVertices[i].z);// 法线 不一定存在vertex.Normal = glm::vec3(mesh->mNormals[i].x, mesh->mNormals[i].y, mesh->mNormals[i].z);// 纹理坐标 不一定存在if (mesh->mTextureCoords[0])vertex.TexCoords = glm::vec2(mesh->mTextureCoords[0][i].x, mesh->mTextureCoords[0][i].y);elsevertex.TexCoords = glm::vec2(0.0f, 0.0f);vertices.push_back(vertex);}// 处理索引for (unsigned int i = 0; i < mesh->mNumFaces; i++){// 处理该网格的每个面aiFace face = mesh->mFaces[i];for (unsigned int j = 0; j < face.mNumIndices; j++)indices.push_back(face.mIndices[j]);}// 处理材质if (mesh->mMaterialIndex >= 0){// 索引场景对象获得该网格对应的材质数据aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];vector<Texture> diffuseMaps = loadMaterialTextures(material, aiTextureType_DIFFUSE, "texture_diffuse");vector<Texture> specularMaps = loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());}return Mesh(vertices, indices, textures);
}vector<Texture> Model::loadMaterialTextures(aiMaterial* mat, aiTextureType type, const string& typeName)
{vector<Texture> textures;// 类型为type的纹理个数for (unsigned int i = 0; i < mat->GetTextureCount(type); i++){aiString textureFilePosition;// 得到纹理文件的位置 存储在textureFilePosition中mat->GetTexture(type, i, &textureFilePosition);string str(textureFilePosition.C_Str());auto it = texturesHashTable.find(str);if (it == texturesHashTable.end()){// 未加载过texturesHashTable[str] = texturesLoaded.size();// 读取obj时已经翻转了纹理坐标 此处不需要再翻转图片y轴了Texture texture(typeName, directory + "/" + str, false);texturesLoaded.push_back(texture);textures.push_back(texture);}else{// 已经加载过了textures.push_back(texturesLoaded[it->second]);}}return textures;
}
shader:shader:shader:
#version 330 core
layout (location = 0) in vec3 aPos; // 位置变量的属性位置值为 0
layout (location = 1) in vec3 aNormal;
layout (location = 2) in vec2 aTexCoords;uniform mat4 model; //模型
uniform mat4 view; //观察
uniform mat4 projection; //投影out vec2 TexCoords;void main()
{TexCoords = aTexCoords;// 注意乘法要从右向左读gl_Position = projection * view * model * vec4(aPos, 1.0);
}
#version 330 core#define MAX_TEXTURE_NUM 8struct Material
{sampler2D texture_diffuse[MAX_TEXTURE_NUM];sampler2D texture_specular[MAX_TEXTURE_NUM];int texture_diffuse_num;int texture_specular_num;
};uniform Material material;in vec2 TexCoords;out vec4 FragColor; void main()
{FragColor = vec4(0.0,0.0,0.0,0.0);for(int i = 0; i < material.texture_diffuse_num; i++){FragColor += texture(material.texture_diffuse[i], TexCoords);}FragColor.a = 1.0;
}main:main:main:
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <iostream>
#include "shader.h"
#include "stb_image.h"
#include "camera.h"
#include "texture.h"
#include "model.h"
using std::cout;//窗口回调函数
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{//绘图视口 3D坐标到2D坐标的转换(映射)和这些参数(宽高)有关glViewport(0, 0, width, height);
}//键盘回调
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);//鼠标回调
void mouse_callback(GLFWwindow* window, double xpos, double ypos);//滚轮回调
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);//窗口初始大小
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;//物体着色器
const char* vShaderPath = "ShaderFiles/shader.vert";
const char* fShaderPath = "ShaderFiles/shader.frag";
//光源着色器
const char* lightvShaderPath = "ShaderFiles/light_shader.vert";
const char* lightfShaderPath = "ShaderFiles/light_shader.frag";//混合颜色的插值
float mixValue = 0.2f;
//记录鼠标坐标
float lastX, lastY;
bool firstMouse = true;//摄像机
Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));//光源位置
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);int main()
{//glfw初始化glfwInit();//告诉glfw我们所使用的opengl版本 此处为3.3glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);//创建窗口GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);if (window == NULL){cout << "Failed to create GLFW window\n";glfwTerminate();return -1;}glfwMakeContextCurrent(window);glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);//设置窗口回调函数glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);//键盘回调函数glfwSetKeyCallback(window, key_callback);//鼠标回调glfwSetCursorPosCallback(window, mouse_callback);//滚轮回调glfwSetScrollCallback(window, scroll_callback);if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){cout << "Failed to initialize GLAD\n";return -1;}//开启深度测试glEnable(GL_DEPTH_TEST);//着色器对象Shader shaderProgram = Shader(vShaderPath, fShaderPath);Shader lightShaderProgram = Shader(lightvShaderPath, lightfShaderPath);// light positionsfloat vertices[] = {-0.5f, -0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, 0.5f, -0.5f,0.5f, 0.5f, -0.5f,-0.5f, 0.5f, -0.5f,-0.5f, -0.5f, -0.5f,-0.5f, -0.5f, 0.5f,0.5f, -0.5f, 0.5f,0.5f, 0.5f, 0.5f,0.5f, 0.5f, 0.5f,-0.5f, 0.5f, 0.5f,-0.5f, -0.5f, 0.5f,-0.5f, 0.5f, 0.5f,-0.5f, 0.5f, -0.5f,-0.5f, -0.5f, -0.5f,-0.5f, -0.5f, -0.5f,-0.5f, -0.5f, 0.5f,-0.5f, 0.5f, 0.5f,0.5f, 0.5f, 0.5f,0.5f, 0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, -0.5f, 0.5f,0.5f, 0.5f, 0.5f,-0.5f, -0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, -0.5f, 0.5f,0.5f, -0.5f, 0.5f,-0.5f, -0.5f, 0.5f,-0.5f, -0.5f, -0.5f,-0.5f, 0.5f, -0.5f,0.5f, 0.5f, -0.5f,0.5f, 0.5f, 0.5f,0.5f, 0.5f, 0.5f,-0.5f, 0.5f, 0.5f,-0.5f, 0.5f, -0.5f,};//物体(obj)Model modelObj("Obj/Nanosuit/nanosuit.obj");//光源unsigned int lightVAO;unsigned int lightVBO;glGenVertexArrays(1, &lightVAO);glBindVertexArray(lightVAO);glGenBuffers(1, &lightVBO);glBindBuffer(GL_ARRAY_BUFFER, lightVBO);glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);glEnableVertexAttribArray(0);//线框模式//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);//这些uniform不会更新 可以放到循环外面while (!glfwWindowShouldClose(window)){glClearColor(0.05f, 0.05f, 0.05f, 1.0f);glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);//矩阵运算glm::mat4 view = camera.GetViewMatrix();glm::mat4 projection = glm::perspective(glm::radians(camera.Fov), SCR_WIDTH * 1.0f / SCR_HEIGHT, 0.1f, 100.0f);glm::mat4 model(1.0f);model = glm::scale(model, glm::vec3(0.25f, 0.25f, 0.25f));//激活着色器shaderProgram.use();shaderProgram.setMat4("model", model);shaderProgram.setMat4("view", view);shaderProgram.setMat4("projection", projection);glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);modelObj.Draw(shaderProgram);model = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, 2.0f));model = glm::rotate(model, glm::radians(180.f), glm::vec3(0.0f, 1.0f, 0.0f));model = glm::scale(model, glm::vec3(0.25f, 0.25f, 0.25f));shaderProgram.setMat4("model", model);glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);modelObj.Draw(shaderProgram);glfwSwapBuffers(window);glfwPollEvents();}//这一步是可选的glDeleteVertexArrays(1, &lightVAO);glDeleteBuffers(1, &lightVBO);//glDeleteBuffers(1, &EBO);//释放资源glfwTerminate();return 0;
}void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{if (action == GLFW_REPEAT || action == GLFW_PRESS){if (key == GLFW_KEY_ESCAPE){glfwSetWindowShouldClose(window, GL_TRUE);return;}switch (key){case GLFW_KEY_UP:mixValue += 0.1f;if (mixValue >= 1.0f)mixValue = 1.0f;break;case GLFW_KEY_DOWN:mixValue -= 0.1f;if (mixValue <= 0.0f)mixValue = 0.0f;break;case GLFW_KEY_W:camera.ProcessKeyboard(FORWARD);break;case GLFW_KEY_S:camera.ProcessKeyboard(BACKWARD);break;case GLFW_KEY_A:camera.ProcessKeyboard(LEFT);break;case GLFW_KEY_D:camera.ProcessKeyboard(RIGHT);break;default:break;}}
}void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{if (firstMouse){firstMouse = false;lastX = xpos, lastY = ypos;}camera.ProcessMouseMovement(xpos - lastX, lastY - ypos);lastX = xpos;lastY = ypos;
}void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{camera.ProcessMouseScroll(yoffset);
}
下一步：加入镜面光贴图和光源！
shader:shader:shader:
#version 330 core
layout (location = 0) in vec3 aPos; // 位置变量的属性位置值为 0
layout (location = 1) in vec3 aNormal;
layout (location = 2) in vec2 aTexCoords;uniform mat4 model; //模型
uniform mat4 view; //观察
uniform mat4 projection; //投影out vec3 Normal;
out vec3 FragPos;
out vec2 TexCoords;void main()
{Normal = mat3(transpose(inverse(model))) * aNormal;FragPos = vec3(model * vec4(aPos, 1.0));TexCoords = aTexCoords;// 注意乘法要从右向左读gl_Position = projection * view * model * vec4(aPos, 1.0);
}#version 330 core#define MAX_TEXTURE_NUM 8struct Material
{sampler2D texture_diffuse[MAX_TEXTURE_NUM];sampler2D texture_specular[MAX_TEXTURE_NUM];int texture_diffuse_num;int texture_specular_num;float shininess;
};// 方向光
struct DirLight
{vec3 direction;vec3 ambient;vec3 diffuse;vec3 specular;
};// 点光源
struct PointLight
{vec3 position;vec3 ambient;vec3 diffuse;vec3 specular;float constant;float linear;float quadratic;
};// 聚光-手电筒
struct SpotLight
{vec3 position;vec3 direction;vec3 ambient;vec3 diffuse;vec3 specular;// 内圆锥余弦值float cutOff;// 外圆锥余弦值float outerCutOff;float constant;float linear;float quadratic;
};in vec3 Normal;
in vec3 FragPos;
in vec2 TexCoords;out vec4 FragColor; uniform vec3 viewPos;uniform Material material;uniform DirLight dirLight;
#define NR_POINT_LIGHTS 2
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform SpotLight spotLight;vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir);
vec3 CalPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
vec3 CalSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
vec3 CalLightSum(vec3 lightAmbient, vec3 lightDiffuse, vec3 lightSpecular, float diff, float spec);void main()
{vec3 norm = normalize(Normal);vec3 viewDir = normalize(viewPos - FragPos);// 定向光照vec3 result = CalcDirLight(dirLight, norm, viewDir);// 点光源for(int i = 0; i < NR_POINT_LIGHTS; i++)result += CalPointLight(pointLights[i], norm, FragPos, viewDir);// 聚光result += CalSpotLight(spotLight, norm, FragPos, viewDir);FragColor = vec4(result, 1.0);
}// 计算某个方向光源对该片段颜色的贡献
vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir)
{vec3 lightDir = normalize(-light.direction);// 漫反射着色float diff = max(dot(normal,lightDir),0.0);// 镜面光着色vec3 reflectDir = reflect(-lightDir,normal);float spec = pow(max(dot(viewDir,reflectDir),0.0),material.shininess);// 合并return CalLightSum(light.ambient, light.diffuse, light.specular, diff, spec);
}// 计算某个点光源对该片段颜色的贡献
vec3 CalPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{vec3 lightDir = normalize(light.position - fragPos);// 漫反射着色float diff = max(dot(normal,lightDir),0.0);// 镜面光着色vec3 reflectDir = reflect(-lightDir,normal);float spec = pow(max(dot(viewDir,reflectDir),0.0),material.shininess);// 距离float dis = length(light.position - fragPos);// 衰减float attenuation = 1.0 / (light.constant + light.linear * dis + light.quadratic * dis *dis);// 合并return CalLightSum(light.ambient, light.diffuse, light.specular, diff, spec) * attenuation;
}// 计算某个聚光灯源对该片段颜色的贡献
vec3 CalSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{vec3 lightDir = normalize(light.position - fragPos);// 漫反射着色float diff = max(dot(normal,lightDir),0.0);// 镜面光着色vec3 reflectDir = reflect(-lightDir,normal);float spec = pow(max(dot(viewDir,reflectDir),0.0),material.shininess);// 距离float dis = length(light.position - fragPos);// 衰减float attenuation = 1.0 /(light.constant + light.linear * dis + light.quadratic * dis * dis);// 内外光切角插值 实现平滑过度效果float cosTheta = dot(lightDir, normalize(-light.direction));float epsilon = light.cutOff - light.outerCutOff;float intensity = clamp((cosTheta - light.outerCutOff) / epsilon, 0.0, 1.0);// 合并return CalLightSum(light.ambient, light.diffuse, light.specular, diff, spec) * attenuation * intensity;
}// 计算环境光、漫反射、镜面光的颜色和
// 没有计算衰减
vec3 CalLightSum(vec3 lightAmbient, vec3 lightDiffuse, vec3 lightSpecular, float diff, float spec)
{vec3 diffuse = vec3(0.0,0.0,0.0);for(int i = 0; i < material.texture_diffuse_num; i++){diffuse += texture(material.texture_diffuse[i], TexCoords).rgb;}vec3 ambient = lightAmbient * diffuse;diffuse = lightDiffuse * diff * diffuse;vec3 specular = vec3(0.0,0.0,0.0);for(int i = 0; i < material.texture_specular_num; i++){specular += texture(material.texture_specular[i], TexCoords).rgb;}specular = lightSpecular * spec * specular;return ambient + diffuse + specular;
}main:main:main:
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <iostream>
#include "shader.h"
#include "stb_image.h"
#include "camera.h"
#include "light.h"
#include "texture.h"
#include "model.h"
using std::cout;//窗口回调函数
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{//绘图视口 3D坐标到2D坐标的转换(映射)和这些参数(宽高)有关glViewport(0, 0, width, height);
}//键盘回调
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);//鼠标回调
void mouse_callback(GLFWwindow* window, double xpos, double ypos);//滚轮回调
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);//窗口初始大小
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;//物体着色器
const char* vShaderPath = "ShaderFiles/shader.vert";
const char* fShaderPath = "ShaderFiles/shader.frag";
//光源着色器
const char* lightvShaderPath = "ShaderFiles/shader.vert";
const char* lightfShaderPath = "ShaderFiles/light_shader.frag";//混合颜色的插值
float mixValue = 0.2f;
//记录鼠标坐标
float lastX, lastY;
bool firstMouse = true;//摄像机
Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));//光源位置
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);int main()
{//glfw初始化glfwInit();//告诉glfw我们所使用的opengl版本 此处为3.3glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);//创建窗口GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);if (window == NULL){cout << "Failed to create GLFW window\n";glfwTerminate();return -1;}glfwMakeContextCurrent(window);glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);//设置窗口回调函数glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);//键盘回调函数glfwSetKeyCallback(window, key_callback);//鼠标回调glfwSetCursorPosCallback(window, mouse_callback);//滚轮回调glfwSetScrollCallback(window, scroll_callback);if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){cout << "Failed to initialize GLAD\n";return -1;}//开启深度测试glEnable(GL_DEPTH_TEST);//着色器对象Shader shaderProgram = Shader(vShaderPath, fShaderPath);Shader lightShaderProgram = Shader(lightvShaderPath, lightfShaderPath);// light positionsfloat vertices[] = {-0.5f, -0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, 0.5f, -0.5f,0.5f, 0.5f, -0.5f,-0.5f, 0.5f, -0.5f,-0.5f, -0.5f, -0.5f,-0.5f, -0.5f, 0.5f,0.5f, -0.5f, 0.5f,0.5f, 0.5f, 0.5f,0.5f, 0.5f, 0.5f,-0.5f, 0.5f, 0.5f,-0.5f, -0.5f, 0.5f,-0.5f, 0.5f, 0.5f,-0.5f, 0.5f, -0.5f,-0.5f, -0.5f, -0.5f,-0.5f, -0.5f, -0.5f,-0.5f, -0.5f, 0.5f,-0.5f, 0.5f, 0.5f,0.5f, 0.5f, 0.5f,0.5f, 0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, -0.5f, 0.5f,0.5f, 0.5f, 0.5f,-0.5f, -0.5f, -0.5f,0.5f, -0.5f, -0.5f,0.5f, -0.5f, 0.5f,0.5f, -0.5f, 0.5f,-0.5f, -0.5f, 0.5f,-0.5f, -0.5f, -0.5f,-0.5f, 0.5f, -0.5f,0.5f, 0.5f, -0.5f,0.5f, 0.5f, 0.5f,0.5f, 0.5f, 0.5f,-0.5f, 0.5f, 0.5f,-0.5f, 0.5f, -0.5f,};//物体(obj)Model modelObj("Obj/Nanosuit/nanosuit.obj");//光源unsigned int lightVAO;unsigned int lightVBO;glGenVertexArrays(1, &lightVAO);glBindVertexArray(lightVAO);glGenBuffers(1, &lightVBO);glBindBuffer(GL_ARRAY_BUFFER, lightVBO);glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);glEnableVertexAttribArray(0);DirLight dirLight(glm::vec3(-0.2f, -1.0f, -0.3f), glm::vec3(0.05f, 0.05f, 0.05f), glm::vec3(0.4f, 0.4f, 0.4f), glm::vec3(0.5f, 0.5f, 0.5f));glm::vec3 pointLightPositions[] = {glm::vec3(-2.0f,4.0f,1.0f),glm::vec3(2.0f,1.0f,0.0f)};PointLight pointLights[] = {PointLight(pointLightPositions[0],glm::vec3(0.05f,0.05f,0.05f),glm::vec3(0.8f,0.8f,0.8f),glm::vec3(1.0f,1.0f,1.0f)),PointLight(pointLightPositions[1],glm::vec3(0.05f,0.05f,0.05f),glm::vec3(0.8f,0.8f,0.8f),glm::vec3(1.0f,1.0f,1.0f)),};SpotLight spotLight(camera.Position, camera.Front, glm::vec3(0.2f, 0.2f, 0.2f), glm::vec3(0.5f, 0.5f, 0.5f), glm::vec3(1.0f, 1.0f, 1.0f));//线框模式//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);//这些uniform不会更新 可以放到循环外面shaderProgram.use();shaderProgram.setFloat("material.shininess", 32.0f);setLightAllAttribute(shaderProgram, "dirLight", &dirLight);setLightAllAttribute(shaderProgram, "pointLights", pointLights, 2);lightShaderProgram.use();lightShaderProgram.setVec3("lightColor", glm::vec3(1.0, 1.0, 1.0));while (!glfwWindowShouldClose(window)){glClearColor(0.05f, 0.05f, 0.05f, 1.0f);glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);//矩阵运算glm::mat4 view = camera.GetViewMatrix();glm::mat4 projection = glm::perspective(glm::radians(camera.Fov), SCR_WIDTH * 1.0f / SCR_HEIGHT, 0.1f, 100.0f);glm::mat4 model(1.0f);model = glm::scale(model, glm::vec3(0.25f, 0.25f, 0.25f));//激活着色器shaderProgram.use();shaderProgram.setMat4("model", model);shaderProgram.setMat4("view", view);shaderProgram.setMat4("projection", projection);shaderProgram.setVec3("viewPos", camera.Position);spotLight.position = camera.Position;spotLight.direction = camera.Front;setLightAllAttribute(shaderProgram, "spotLight", &spotLight);modelObj.Draw(shaderProgram);model = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, 2.0f));model = glm::rotate(model, glm::radians(180.f), glm::vec3(0.0f, 1.0f, 0.0f));model = glm::scale(model, glm::vec3(0.25f, 0.25f, 0.25f));shaderProgram.setMat4("model", model);modelObj.Draw(shaderProgram);lightShaderProgram.use();lightShaderProgram.setMat4("view", view);lightShaderProgram.setMat4("projection", projection);glBindVertexArray(lightVAO);for (unsigned int i = 0; i < 2; i++){glm::mat4 lightModel(1.0f);lightModel = glm::translate(lightModel, pointLightPositions[i]);lightModel = glm::scale(lightModel, glm::vec3(0.2f, 0.2f, 0.2f));lightShaderProgram.setMat4("model", lightModel);glDrawArrays(GL_TRIANGLES, 0, 36);}glfwSwapBuffers(window);glfwPollEvents();}//这一步是可选的glDeleteVertexArrays(1, &lightVAO);glDeleteBuffers(1, &lightVBO);//glDeleteBuffers(1, &EBO);//释放资源glfwTerminate();return 0;
}void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{if (action == GLFW_REPEAT || action == GLFW_PRESS){if (key == GLFW_KEY_ESCAPE){glfwSetWindowShouldClose(window, GL_TRUE);return;}switch (key){case GLFW_KEY_UP:mixValue += 0.1f;if (mixValue >= 1.0f)mixValue = 1.0f;break;case GLFW_KEY_DOWN:mixValue -= 0.1f;if (mixValue <= 0.0f)mixValue = 0.0f;break;case GLFW_KEY_W:camera.ProcessKeyboard(FORWARD);break;case GLFW_KEY_S:camera.ProcessKeyboard(BACKWARD);break;case GLFW_KEY_A:camera.ProcessKeyboard(LEFT);break;case GLFW_KEY_D:camera.ProcessKeyboard(RIGHT);break;default:break;}}
}void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{if (firstMouse){firstMouse = false;lastX = xpos, lastY = ypos;}camera.ProcessMouseMovement(xpos - lastX, lastY - ypos);lastX = xpos;lastY = ypos;
}void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{camera.ProcessMouseScroll(yoffset);
}
甚至我都必须要承认这个可能是比一直使用的箱子要好看多了。使用Assimp，你能够加载互联网上的无数模型。有很多资源网站都提供了多种格式的免费3D模型供你下载。但还是要注意，有些模型会不能正常地载入，纹理的路径会出现问题，或者Assimp并不支持它的格式。
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