wordpress 站点图标,金华公司网站建设,网页源码怎么做网站,公司企业网站建设的建站流程解析9.9.2 model 模型
一个模型拥有多个网格组成#xff0c;并配有相应的处理函数#xff0c;如节点处理、网格处理、加载模型、加载纹理、渲染等
模型类#xff1a;
class Model{
public:Model(char* path) {loadModel(path);}void Draw(Shader shader);private:std::vector…9.9.2 model 模型
一个模型拥有多个网格组成并配有相应的处理函数如节点处理、网格处理、加载模型、加载纹理、渲染等
模型类
class Model{
public:Model(char* path) {loadModel(path);}void Draw(Shader shader);private:std::vectorMesh meshes;std::string directory;void loadModel(std::string path);void processNode(aiNode* node, const aiScene* scene);Mesh processMesh(aiMesh* mesh, const aiScene* scene);std::vectorTexture loadMaterialtextures(aiMaterial* mat, aiTextureType type, std::string typeName);
};下面介绍相关函数
1draw 函数
这函数只需要遍历成员变量meshes调用每个mesh的Draw函数就可以了。
//渲染
void Model::Draw(Shader shader) {for (int i 0; i meshes.size(); i)meshes[i].Draw(shader);
}2loadModel
在这函数中我们会把模型用Assimp加载进来保存成一个scene对象。这是Assimp的一个根对象。模型加载成scene对象之后我们就可以从里面读取数据进行转换纹理。
//加载模型
void Model::loadModel(std::string path) {//导入成scene对象Assimp::Importer importer;const aiScene* scene importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);//检测是否成功if (!scene || scene-mFlags AI_SCENE_FLAGS_INCOMPLETE || !scene-mRootNode) {std::cout Assimp加载模型失败错误信息: importer.GetErrorString() std::endl;return;}directory path.substr(0, path.find_last_of(/));processNode(scene-mRootNode, scene);
}3processNode
processNode来处理节点数据每一个节点都可能包含子节点所以这个函数会在其内部进行递归调用。Assimp的节点类中包含一些网格索引信息检索和处理每个网格是我们的函数要做的主要事情。
//处理节点
void Model::processNode(aiNode* node, const aiScene* scene) {//处理节点的所有网格信息for (int i 0; i node-mNumMeshes; i) {aiMesh* mesh scene-mMeshes[node-mMeshes[i]];meshes.push_back(processMesh(mesh, scene));}//对所有的子节点做相同处理for (int i 0; i node-mNumChildren; i) {processNode(node-mChildren[i], scene);}
}4processMesh
将一个aiMesh对象转换成我们的mesh对象并不难我们所要做的就是获取aiMesh中网格的所有属性然后将其保存到mesh对象中。
//处理网格
Mesh Model::processMesh(aiMesh* mesh, const aiScene* scene) {std::vectorVertex vertices;std::vectorunsigned int indices;std::vectorTexture textures;for (int i 0; i mesh-mNumVertices; i) {Vertex vertex;//处理顶点法线和纹理坐标...vertices.push_back(vertex);}//处理索引...//处理材质if (mesh-mMaterialIndex 0) {...}return Mesh(vertices, indices, textures);
}processMesh中网格处理
收拾一个网格基本上有三个步骤要做检索所有的顶点数据、检索所有的网格索引、检索相关的材质数据。将处理完成的数据保存到3个向量中传递给Mesh的构造函数生成一个新的Mesh对象返回。
检索顶点数据在mVertices位置mNormals法线mTextureCoords纹理坐标
//处理顶点法线和纹理坐标
glm::vec3 vector;
vector.x mesh-mVertices[i].x;
vector.y mesh-mVertices[i].y;
vector.z mesh-mVertices[i].z;
vertex.Position vector;vector.x mesh-mNormals[i].x;
vector.y mesh-mNormals[i].y;
vector.z mesh-mNormals[i].z;
vertex.Normal vector;if (mesh-mTextureCoords[0]) { //看看是否有纹理信息glm::vec2 vec;vec.x mesh-mTextureCoords[0][i].x;vec.y mesh-mTextureCoords[0][i].y;vertex.TexCoords vec;
}
elsevertex.TexCoords glm::vec2(0.0f, 0.0f);检索索引
//处理索引
for (int i 0; i mesh-mNumFaces; i) {aiFace face mesh-mFaces[i];for (int j 0; j face.mNumIndices; j)indices.push_back(face.mIndices[j]);
}相关材质
//处理材质
if (mesh-mMaterialIndex 0) {aiMaterial* material scene-mMaterials[mesh-mMaterialIndex];std::vectorTexture diffuseMaps loadMaterialtextures(material,aiTextureType_DIFFUSE, texture_diffuse);textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());std::vectorTexture specularMaps loadMaterialtextures(material,aiTextureType_SPECULAR, texture_specular);textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
}std::vectorTexture Model::loadMaterialtextures(aiMaterial* mat, aiTextureType type, std::string typeName) {std::vectorTexture textures;for (int i 0; i mat-GetTextureCount(type); i) {aiString str;mat-GetTexture(type, i, str);Texture texture;texture.id TextureFromFile(str.C_Str(), directory);texture.type typeName;texture.path str.C_Str();textures.push_back(texture);}return textures;
}纹理复用加载纹理前先搜索已经加载的纹理如果没加载过就加载加载过了直接保存。
std::vectorTexture Model::loadMaterialtextures(aiMaterial* mat, aiTextureType type, std::string typeName) {std::vectorTexture textures;for (int i 0; i mat-GetTextureCount(type); i) {aiString str;mat-GetTexture(type, i, str);bool skip false;for (int j 0; j textures_loaded.size(); j) {if (std::strcmp(textures_loaded[j].path.c_str(), str.C_Str()) 0) {textures.push_back(textures_loaded[j]);skip true;break;}}if (!skip) {Texture texture;texture.id TextureFromFile(str.C_Str(), directory);texture.type typeName;texture.path str.C_Str();textures.push_back(texture);textures_loaded.push_back(texture);}}return textures;
}完整代码
#ifndef MODEL_H
#define MODEL_H#include glad/glad.h #include glm/glm.hpp
#include glm/gtc/matrix_transform.hpp
#include stb_image.h
#include assimp/Importer.hpp
#include assimp/scene.h
#include assimp/postprocess.h#include learnopengl/mesh.h
#include learnopengl/shader.h#include string
#include fstream
#include sstream
#include iostream
#include map
#include vector
using namespace std;unsigned int TextureFromFile(const char *path, const string directory, bool gamma false);class Model
{
public:// model data vectorTexture textures_loaded; // stores all the textures loaded so far, optimization to make sure textures arent loaded more than once.vectorMesh meshes;string directory;bool gammaCorrection;// constructor, expects a filepath to a 3D model.Model(string const path, bool gamma false) : gammaCorrection(gamma){loadModel(path);}// draws the model, and thus all its meshesvoid Draw(Shader shader){for(unsigned int i 0; i meshes.size(); i)meshes[i].Draw(shader);}private:// loads a model with supported ASSIMP extensions from file and stores the resulting meshes in the meshes vector.void loadModel(string const path){// read file via ASSIMPAssimp::Importer importer;const aiScene* scene importer.ReadFile(path, aiProcess_Triangulate | aiProcess_GenSmoothNormals | aiProcess_FlipUVs | aiProcess_CalcTangentSpace);// check for errorsif(!scene || scene-mFlags AI_SCENE_FLAGS_INCOMPLETE || !scene-mRootNode) // if is Not Zero{cout ERROR::ASSIMP:: importer.GetErrorString() endl;return;}// retrieve the directory path of the filepathdirectory path.substr(0, path.find_last_of(/));// process ASSIMPs root node recursivelyprocessNode(scene-mRootNode, scene);}// processes a node in a recursive fashion. Processes each individual mesh located at the node and repeats this process on its children nodes (if any).void processNode(aiNode *node, const aiScene *scene){// process each mesh located at the current nodefor(unsigned int i 0; i node-mNumMeshes; i){// the node object only contains indices to index the actual objects in the scene. // the scene contains all the data, node is just to keep stuff organized (like relations between nodes).aiMesh* mesh scene-mMeshes[node-mMeshes[i]];meshes.push_back(processMesh(mesh, scene));}// after weve processed all of the meshes (if any) we then recursively process each of the children nodesfor(unsigned int i 0; i node-mNumChildren; i){processNode(node-mChildren[i], scene);}}Mesh processMesh(aiMesh *mesh, const aiScene *scene){// data to fillvectorVertex vertices;vectorunsigned int indices;vectorTexture textures;// walk through each of the meshs verticesfor(unsigned int i 0; i mesh-mNumVertices; i){Vertex vertex;glm::vec3 vector; // we declare a placeholder vector since assimp uses its own vector class that doesnt directly convert to glms vec3 class so we transfer the data to this placeholder glm::vec3 first.// positionsvector.x mesh-mVertices[i].x;vector.y mesh-mVertices[i].y;vector.z mesh-mVertices[i].z;vertex.Position vector;// normalsif (mesh-HasNormals()){vector.x mesh-mNormals[i].x;vector.y mesh-mNormals[i].y;vector.z mesh-mNormals[i].z;vertex.Normal vector;}// texture coordinatesif(mesh-mTextureCoords[0]) // does the mesh contain texture coordinates?{glm::vec2 vec;// a vertex can contain up to 8 different texture coordinates. We thus make the assumption that we wont // use models where a vertex can have multiple texture coordinates so we always take the first set (0).vec.x mesh-mTextureCoords[0][i].x; vec.y mesh-mTextureCoords[0][i].y;vertex.TexCoords vec;// tangentvector.x mesh-mTangents[i].x;vector.y mesh-mTangents[i].y;vector.z mesh-mTangents[i].z;vertex.Tangent vector;// bitangentvector.x mesh-mBitangents[i].x;vector.y mesh-mBitangents[i].y;vector.z mesh-mBitangents[i].z;vertex.Bitangent vector;}elsevertex.TexCoords glm::vec2(0.0f, 0.0f);vertices.push_back(vertex);}// now wak through each of the meshs faces (a face is a mesh its triangle) and retrieve the corresponding vertex indices.for(unsigned int i 0; i mesh-mNumFaces; i){aiFace face mesh-mFaces[i];// retrieve all indices of the face and store them in the indices vectorfor(unsigned int j 0; j face.mNumIndices; j)indices.push_back(face.mIndices[j]); }// process materialsaiMaterial* material scene-mMaterials[mesh-mMaterialIndex]; // we assume a convention for sampler names in the shaders. Each diffuse texture should be named// as texture_diffuseN where N is a sequential number ranging from 1 to MAX_SAMPLER_NUMBER. // Same applies to other texture as the following list summarizes:// diffuse: texture_diffuseN// specular: texture_specularN// normal: texture_normalN// 1. diffuse mapsvectorTexture diffuseMaps loadMaterialTextures(material, aiTextureType_DIFFUSE, texture_diffuse);textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());// 2. specular mapsvectorTexture specularMaps loadMaterialTextures(material, aiTextureType_SPECULAR, texture_specular);textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());// 3. normal mapsstd::vectorTexture normalMaps loadMaterialTextures(material, aiTextureType_HEIGHT, texture_normal);textures.insert(textures.end(), normalMaps.begin(), normalMaps.end());// 4. height mapsstd::vectorTexture heightMaps loadMaterialTextures(material, aiTextureType_AMBIENT, texture_height);textures.insert(textures.end(), heightMaps.begin(), heightMaps.end());// return a mesh object created from the extracted mesh datareturn Mesh(vertices, indices, textures);}// checks all material textures of a given type and loads the textures if theyre not loaded yet.// the required info is returned as a Texture struct.vectorTexture loadMaterialTextures(aiMaterial *mat, aiTextureType type, string typeName){vectorTexture textures;for(unsigned int i 0; i mat-GetTextureCount(type); i){aiString str;mat-GetTexture(type, i, str);// check if texture was loaded before and if so, continue to next iteration: skip loading a new texturebool skip false;for(unsigned int j 0; j textures_loaded.size(); j){if(std::strcmp(textures_loaded[j].path.data(), str.C_Str()) 0){textures.push_back(textures_loaded[j]);skip true; // a texture with the same filepath has already been loaded, continue to next one. (optimization)break;}}if(!skip){ // if texture hasnt been loaded already, load itTexture texture;texture.id TextureFromFile(str.C_Str(), this-directory);texture.type typeName;texture.path str.C_Str();textures.push_back(texture);textures_loaded.push_back(texture); // store it as texture loaded for entire model, to ensure we wont unnecessary load duplicate textures.}}return textures;}
};unsigned int TextureFromFile(const char *path, const string directory, bool gamma)
{string filename string(path);filename directory / filename;unsigned int textureID;glGenTextures(1, textureID);int width, height, nrComponents;unsigned char *data stbi_load(filename.c_str(), 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;
}
#endif
