#pragma once
// Std. Includes
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <map>
#include <vector>
using namespace std;
// GL Includes
#include <GL/glew.h> // Contains all the necessery OpenGL includes
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <SOIL.h>
#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>
#include "Mesh.h"
GLint TextureFromFile(const char* path, string directory);
class Model
{
public:
/* Functions */
// Constructor, expects a filepath to a 3D model.
Model(GLchar* path)
{
this->loadModel(path);
}
// Draws the model, and thus all its meshes
void Draw(Shader shader)
{
for(GLuint i = 0; i < this->meshes.size(); i++)
this->meshes[i].Draw(shader);
}
private:
/* Model Data */
vector<Mesh> meshes;
string directory;
vector<Texture> textures_loaded; // Stores all the textures loaded so far, optimization to make sure textures aren't loaded more than once.
/* Functions */
// Loads a model with supported ASSIMP extensions from file and stores the resulting meshes in the meshes vector.
void loadModel(string path)
{
// Read file via ASSIMP
Assimp::Importer importer;
const aiScene* scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);
// Check for errors
if(!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 filepath
this->directory = path.substr(0, path.find_last_of('/'));
// Process ASSIMP's root node recursively
this->processNode(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 node
for(GLuint 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.
aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
this->meshes.push_back(this->processMesh(mesh, scene));
}
// After we've processed all of the meshes (if any) we then recursively process each of the children nodes
for(GLuint i = 0; i < node->mNumChildren; i++)
{
// Child nodes are actually stored in the node, not in the scene (which makes sense since nodes only contain
// links and indices, nothing more, so why store that in the scene)
this->processNode(node->mChildren[i], scene);
}
}
Mesh processMesh(aiMesh* mesh, const aiScene* scene)
{
// Data to fill
vector<Vertex> vertices;
vector<GLuint> indices;
vector<Texture> textures;
// Walk through each of the mesh's vertices
for(GLuint i = 0; i < mesh->mNumVertices; i++)
{
Vertex vertex;
glm::vec3 vector; // We declare a placeholder vector since assimp uses its own vector class that doesn't directly convert to glm's vec3 class so we transfer the data to this placeholder glm::vec3 first.
// Positions
vector.x = mesh->mVertices[i].x;
vector.y = mesh->mVertices[i].y;
vector.z = mesh->mVertices[i].z;
vertex.Position = vector;
// Normals
vector.x = mesh->mNormals[i].x;
vector.y = mesh->mNormals[i].y;
vector.z = mesh->mNormals[i].z;
vertex.Normal = vector;
// Texture Coordinates
if(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 won't
// 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;
}
else
vertex.TexCoords = glm::vec2(0.0f, 0.0f);
vertices.push_back(vertex);
}
// Now wak through each of the mesh's faces (a face is a mesh its triangle) and retrieve the corresponding vertex indices.
for(GLuint i = 0; i < mesh->mNumFaces; i++)
{
aiFace face = mesh->mFaces[i];
// Retrieve all indices of the face and store them in the indices vector
for(GLuint j = 0; j < face.mNumIndices; j++)
indices.push_back(face.mIndices[j]);
}
// Process materials
if(mesh->mMaterialIndex >= 0)
{
aiMaterial* 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 maps
vector<Texture> diffuseMaps = this->loadMaterialTextures(material, aiTextureType_DIFFUSE, "texture_diffuse");
textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());
// 2. Specular maps
vector<Texture> specularMaps = this->loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");
textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
// 3. Reflection maps (Note that ASSIMP doesn't load reflection maps properly from wavefront objects, so we'll cheat a little by defining the reflection maps as ambient maps in the .obj file, which ASSIMP is able to load)
vector<Texture> reflectionMaps = this->loadMaterialTextures(material, aiTextureType_AMBIENT, "texture_reflection");
textures.insert(textures.end(), reflectionMaps.begin(), reflectionMaps.end());
}
// Return a mesh object created from the extracted mesh data
return Mesh(vertices, indices, textures);
}
// Checks all material textures of a given type and loads the textures if they're not loaded yet.
// The required info is returned as a Texture struct.
vector<Texture> loadMaterialTextures(aiMaterial* mat, aiTextureType type, string typeName)
{
vector<Texture> textures;
for(GLuint 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 texture
GLboolean skip = false;
for(GLuint j = 0; j < textures_loaded.size(); j++)
{
if(textures_loaded[j].path == str)
{
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 hasn't been loaded already, load it
Texture texture;
texture.id = TextureFromFile(str.C_Str(), this->directory);
texture.type = typeName;
texture.path = str;
textures.push_back(texture);
this->textures_loaded.push_back(texture); // Store it as texture loaded for entire model, to ensure we won't unnecesery load duplicate textures.
}
}
return textures;
}
};
GLint TextureFromFile(const char* path, string directory)
{
//Generate texture ID and load texture data
string filename = string(path);
filename = directory + '/' + filename;
GLuint textureID;
glGenTextures(1, &textureID);
int width,height;
unsigned char* image = SOIL_load_image(filename.c_str(), &width, &height, 0, SOIL_LOAD_RGB);
// Assign texture to ID
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
// Parameters
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);
glBindTexture(GL_TEXTURE_2D, 0);
SOIL_free_image_data(image);
return textureID;
}
HI