Hello everybody,

I am new to game programming and to OpenGL in general, and after drawing quads and messing around with some effects I decided to load a model. I searched around the internet for a good model loader, and I found ASSIMP (http://assimp.sourceforge.net/), which seemed promising. I was able, through reading the documentation and by using the sample program, to load models and display them on the screen. However, the sample doesn't show you how to texture the models, and because I am new to this, I have no idea how. I searched all over the internet but couldn't find anything. Could someone help me and show me how to load and draw a textured model using ASSIMP?

Thanks in advance for any help you can offer.

Never mind, I figured it out on my own. For those out there that would like to know, this is how I did it:

Model.h:

#ifndef MODEL_H#define MODEL_H#include <SDL.h>#include <SDL_opengl.h>#include <assimp.hpp>#include <assimp.h>#include <aiScene.h>       // Output data structure#include <aiPostProcess.h> // Post processing flags#include <FreeImage.h>#include <vector>#include <iostream>#define aisgl_min(x,y) (x<y?x:y)#define aisgl_max(x,y) (y>x?y:x)struct TextureAndPath{	GLuint hTexture;	aiString pathName;};class Model{private:	std::vector<TextureAndPath> texturesAndPaths;	const struct aiScene* scene;	void recursiveTextureLoad(const struct aiScene *sc, const struct aiNode* nd);	void recursive_render(const struct aiScene *sc, const struct aiNode* nd);	void get_bounding_box_for_node(const struct aiNode* nd, struct aiVector3D* min, struct aiVector3D* max, struct aiMatrix4x4* trafo);	void get_bounding_box(struct aiVector3D* min, struct aiVector3D* max);public:	Model();	~Model();	void LoadModel(const char* fileName);	void Draw();};void color4_to_float4(const struct aiColor4D *c, float f[4]);void set_float4(float f[4], float a, float b, float c, float d);void apply_material(const struct aiMaterial *mtl);// Can't send color down as a pointer to aiColor4D because AI colors are ABGR.void Color4f(const struct aiColor4D *color);#endif

Implementation:

#include "Model.h"Model::Model()	: scene(NULL){}Model::~Model(){}void Model::LoadModel(const char* fileName){	scene = aiImportFile(fileName, aiProcessPreset_TargetRealtime_Quality);	recursiveTextureLoad(scene, scene->mRootNode);}void Model::recursiveTextureLoad(const struct aiScene *sc, const struct aiNode* nd){	int i;	unsigned int n = 0, t;	struct aiMatrix4x4 m = nd->mTransformation;	// update transform	aiTransposeMatrix4(&m);	glPushMatrix();	glMultMatrixf((float*)&m);	// draw all meshes assigned to this node	for (; n < nd->mNumMeshes; ++n) 	{		const struct aiMesh* mesh = sc->mMeshes[nd->mMeshes[n]];		unsigned int cont = aiGetMaterialTextureCount(sc->mMaterials[mesh->mMaterialIndex], aiTextureType_DIFFUSE); 		struct aiString* str = (aiString*)malloc(sizeof(struct aiString)); 		if(cont > 0)		{ 			//aiGetMaterialString(sc->mMaterials[mesh->mMaterialIndex],AI_MATKEY_TEXTURE_DIFFUSE(0),str); 			aiGetMaterialTexture(sc->mMaterials[mesh->mMaterialIndex],aiTextureType_DIFFUSE,0,str,0,0,0,0,0,0); 			// See if another mesh is already using this texture, if so, just copy GLuint instead of remaking entire texture			bool newTextureToBeLoaded = true;			for(int x = 0; x < texturesAndPaths.size(); x++)			{				if(texturesAndPaths[x].pathName == *str)				{					TextureAndPath reusedTexture;					reusedTexture.hTexture = texturesAndPaths[x].hTexture;					reusedTexture.pathName = *str;					texturesAndPaths.push_back(reusedTexture);					newTextureToBeLoaded = false;					std::cout << "Texture reused." << std::endl;					break;				}			}			if(newTextureToBeLoaded)			{				FREE_IMAGE_FORMAT formato = FreeImage_GetFileType(str->data,0);				//Automatocally detects the format(from over 20 formats!) 				FIBITMAP* imagen = FreeImage_Load(formato, str->data); 				FIBITMAP* temp = imagen;				imagen = FreeImage_ConvertTo32Bits(imagen);				FreeImage_Unload(temp);				int w = FreeImage_GetWidth(imagen); 				int h = FreeImage_GetHeight(imagen); 							//Some debugging code 				char* pixeles = (char*)FreeImage_GetBits(imagen);				//FreeImage loads in BGR format, so you need to swap some bytes(Or use GL_BGR). 				//Now generate the OpenGL texture object 				TextureAndPath newTexture;				newTexture.pathName = *str;				glGenTextures(1, &newTexture.hTexture); 							glBindTexture(GL_TEXTURE_2D, newTexture.hTexture);				glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA, w, h, 0, GL_BGRA_EXT,GL_UNSIGNED_BYTE,(GLvoid*)pixeles ); 				//glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);				glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR ); 				glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); 				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); 				glBindTexture(GL_TEXTURE_2D, newTexture.hTexture);							GLenum huboError = glGetError(); 							if(huboError)				{ 					std::cout<<"There was an error loading the texture"<<std::endl; 				}				std::cout << "texture loaded." << std::endl;				texturesAndPaths.push_back(newTexture);			}		} 	}	// Get textures from all children	for (n = 0; n < nd->mNumChildren; ++n)		recursiveTextureLoad(sc, nd->mChildren[n]);}void Model::get_bounding_box_for_node(const struct aiNode* nd, struct aiVector3D* min, struct aiVector3D* max, struct aiMatrix4x4* trafo){	struct aiMatrix4x4 prev; // Use struct keyword to show you want struct version of this, not normal typedef?	unsigned int n = 0, t;	prev = *trafo;	aiMultiplyMatrix4(trafo,&nd->mTransformation);	for (; n < nd->mNumMeshes; ++n) 	{		const struct aiMesh* mesh = scene->mMeshes[nd->mMeshes[n]];		for (t = 0; t < mesh->mNumVertices; ++t) 		{			struct aiVector3D tmp = mesh->mVertices[t];			aiTransformVecByMatrix4(&tmp,trafo);			min->x = aisgl_min(min->x,tmp.x);			min->y = aisgl_min(min->y,tmp.y);			min->z = aisgl_min(min->z,tmp.z);			max->x = aisgl_max(max->x,tmp.x);			max->y = aisgl_max(max->y,tmp.y);			max->z = aisgl_max(max->z,tmp.z);		}	}	for (n = 0; n < nd->mNumChildren; ++n) 		get_bounding_box_for_node(nd->mChildren[n],min,max,trafo);	*trafo = prev;}void Model::get_bounding_box(struct aiVector3D* min, struct aiVector3D* max){	struct aiMatrix4x4 trafo;	aiIdentityMatrix4(&trafo);	min->x = min->y = min->z =  1e10f;	max->x = max->y = max->z = -1e10f;	get_bounding_box_for_node(scene->mRootNode,min,max,&trafo);}void Model::recursive_render(const struct aiScene *sc, const struct aiNode* nd){	int i;	unsigned int n = 0, t;	struct aiMatrix4x4 m = nd->mTransformation;	// update transform	aiTransposeMatrix4(&m);	glPushMatrix();	glMultMatrixf((float*)&m);	// draw all meshes assigned to this node	for (; n < nd->mNumMeshes; ++n)	{		const struct aiMesh* mesh = sc->mMeshes[nd->mMeshes[n]];				if(n < texturesAndPaths.size())			glBindTexture(GL_TEXTURE_2D, texturesAndPaths[n].hTexture);		apply_material(sc->mMaterials[mesh->mMaterialIndex]);		if(mesh->mNormals == NULL)			glDisable(GL_LIGHTING);		else			glEnable(GL_LIGHTING);		if(mesh->mColors[0] != NULL)			glEnable(GL_COLOR_MATERIAL);		else			glDisable(GL_COLOR_MATERIAL);		for (t = 0; t < mesh->mNumFaces; ++t) 		{			const struct aiFace* face = &mesh->mFaces[t];			GLenum face_mode;			switch(face->mNumIndices) 			{				case 1: 					face_mode = GL_POINTS; 					break;				case 2: 					face_mode = GL_LINES; 					break;				case 3: 					face_mode = GL_TRIANGLES; 					break;				default: 					face_mode = GL_POLYGON; 					break;			}			glBegin(face_mode);			for(i = 0; i < face->mNumIndices; i++) 			{				int index = face->mIndices;				if(mesh->mColors[0] != NULL)					Color4f(&mesh->mColors[0][index]);				if(mesh->mNormals != NULL) 					glNormal3fv(&mesh->mNormals[index].x);				if(mesh->HasTextureCoords(0))					glTexCoord2f(mesh->mTextureCoords[0][index].x, mesh->mTextureCoords[0][index].y);				glVertex3fv(&mesh->mVertices[index].x);			}			glEnd();		}	}	// draw all children	for (n = 0; n < nd->mNumChildren; ++n)		recursive_render(sc, nd->mChildren[n]);	glPopMatrix();}void Model::Draw(){	recursive_render(scene, scene->mRootNode);}void color4_to_float4(const struct aiColor4D *c, float f[4]){	f[0] = c->r;	f[1] = c->g;	f[2] = c->b;	f[3] = c->a;}void set_float4(float f[4], float a, float b, float c, float d){	f[0] = a;	f[1] = b;	f[2] = c;	f[3] = d;}void apply_material(const struct aiMaterial *mtl){	float c[4];	GLenum fill_mode;	int ret1, ret2;	struct aiColor4D diffuse;	struct aiColor4D specular;	struct aiColor4D ambient;	struct aiColor4D emission;	float shininess, strength;	int two_sided;	int wireframe;	unsigned int max;	set_float4(c, 0.8f, 0.8f, 0.8f, 1.0f);	if(AI_SUCCESS == aiGetMaterialColor(mtl, AI_MATKEY_COLOR_DIFFUSE, &diffuse))		color4_to_float4(&diffuse, c);	glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, c);	set_float4(c, 0.0f, 0.0f, 0.0f, 1.0f);	if(AI_SUCCESS == aiGetMaterialColor(mtl, AI_MATKEY_COLOR_SPECULAR, &specular))		color4_to_float4(&specular, c);	glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, c);	set_float4(c, 0.2f, 0.2f, 0.2f, 1.0f);	if(AI_SUCCESS == aiGetMaterialColor(mtl, AI_MATKEY_COLOR_AMBIENT, &ambient))		color4_to_float4(&ambient, c);	glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, c);	set_float4(c, 0.0f, 0.0f, 0.0f, 1.0f);	if(AI_SUCCESS == aiGetMaterialColor(mtl, AI_MATKEY_COLOR_EMISSIVE, &emission))		color4_to_float4(&emission, c);	glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, c);	max = 1;	ret1 = aiGetMaterialFloatArray(mtl, AI_MATKEY_SHININESS, &shininess, &max);	max = 1;	ret2 = aiGetMaterialFloatArray(mtl, AI_MATKEY_SHININESS_STRENGTH, &strength, &max);	if((ret1 == AI_SUCCESS) && (ret2 == AI_SUCCESS))		glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, shininess * strength);	else {		glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 0.0f);		set_float4(c, 0.0f, 0.0f, 0.0f, 0.0f);		glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, c);	}	max = 1;	if(AI_SUCCESS == aiGetMaterialIntegerArray(mtl, AI_MATKEY_ENABLE_WIREFRAME, &wireframe, &max))		fill_mode = wireframe ? GL_LINE : GL_FILL;	else		fill_mode = GL_FILL;	glPolygonMode(GL_FRONT_AND_BACK, fill_mode);	max = 1;	if((AI_SUCCESS == aiGetMaterialIntegerArray(mtl, AI_MATKEY_TWOSIDED, &two_sided, &max)) && two_sided)		glEnable(GL_CULL_FACE);	else 		glDisable(GL_CULL_FACE);}void Color4f(const struct aiColor4D *color){	glColor4f(color->r, color->g, color->b, color->a);}

As you can see, it is still based off of the original demo code, but adds textures and a texture manager.