OBJ Loader

Functions for loading and managing 3D models from OBJ files. More...

Classes
struct	Face
	Structure representing a face of a 3D model. More...
struct	LoadingModelBuffer
	Structure to hold the data of a 3D model being loaded. More...

Macros
#define	MAX_VERTEX_PER_FACE   10
	Maximum number of vertices per face.

Functions
int	malloc_obj (ModelObjectData *obj, LoadingModelBuffer *buffer, u32 vim, u32 fim, u32 vnim, u32 vtim)
	Allocates memory for an ModelObjectData's vertex, face, normal, and texture data.
void	close_realloc_obj (ModelObjectData *obj, LoadingModelBuffer *buffer, u32 vi, u32 fi, u32 vni, u32 vti)
	Cleans up and reallocates the memory for the vertex data and faces of a 3D object, and generates the Vertex Array Object (VAO) for rendering.
int	load_obj_model (const char *path, ModelData *modelPtr)
	Loads a 3D model from an OBJ file, including its associated materials, vertices, normals, and texture coordinates.

Variables
Vertex *	LoadingModelBuffer::vertex
Normal *	LoadingModelBuffer::normals
TextureVertex *	LoadingModelBuffer::textureVertex
Face *	LoadingModelBuffer::faces

Detailed Description

Functions for loading and managing 3D models from OBJ files.

Macro Definition Documentation

MAX_VERTEX_PER_FACE

#define MAX_VERTEX_PER_FACE   10

Maximum number of vertices per face.

Function Documentation

malloc_obj()

int malloc_obj	(	ModelObjectData *	obj,
		LoadingModelBuffer *	buffer,
		u32	vim,
		u32	fim,
		u32	vnim,
		u32	vtim
	)

Allocates memory for an ModelObjectData's vertex, face, normal, and texture data.

Parameters

obj	{ModelObjectData*} A pointer to the ModelObjectData structure to be initialized.
vim	{u32} The initial number of vertices to allocate memory for.
fim	{u32} The initial number of faces to allocate memory for.
vnim	{u32} The initial number of normals to allocate memory for.
vtim	{u32} The initial number of texture coordinates to allocate memory for.

This function allocates the necessary memory for various data fields in the specified ModelObjectData, including vertices, faces, normals, and texture coordinates. It initializes the materials and materialsLength to NULL and sets the materialsCount to zero.

Important Notes:

• The function assumes that obj is a valid pointer to an ModelObjectData structure.
• If any memory allocation fails, a pointer check function (POINTER_CHECK) should handle the error, potentially freeing previously allocated memory and terminating the program or logging the error.

Example Usage: malloc_obj(&object, initialVertexCount, initialFaceCount, initialNormalCount, initialTextureVertexCount);

Returns

Returns 0 on successful memory allocation.

close_realloc_obj()

void close_realloc_obj	(	ModelObjectData *	obj,
		LoadingModelBuffer *	buffer,
		u32	vi,
		u32	fi,
		u32	vni,
		u32	vti
	)

Cleans up and reallocates the memory for the vertex data and faces of a 3D object, and generates the Vertex Array Object (VAO) for rendering.

Parameters

obj	{ModelObjectData*} A pointer to the ModelObjectData structure to be cleaned up and reallocated.
vi	{u32} The current number of vertices loaded for the object.
fi	{u32} The current number of faces loaded for the object.
vni	{u32} The current number of normals loaded for the object.
vti	{u32} The current number of texture coordinates loaded for the object.

This function frees the previously allocated memory for normals, texture vertices, and vertex data associated with the given ModelObjectData structure. It then reallocates the facesVertex array to fit the actual number of faces and generates the corresponding Vertex Array Object (VAO) for rendering.

Important Notes:

• This function assumes that the ModelObjectData structure has been allocated and initialized properly before calling.
• After calling this function, the obj->facesVertex will point to a reallocated array suitable for the number of faces currently stored.
• Any previously allocated memory for normals, texture vertices, and vertex data will be released, preventing memory leaks.
• It is the caller's responsibility to ensure that obj is valid and that vi, fi, vni, and vti are correctly provided to reflect the current state of the object.

Example Usage: close_realloc_obj(&object, vi, fi, vni, vti);

load_obj_model()

int load_obj_model	(	const char *	path,
		ModelData *	modelPtr
	)

Loads a 3D model from an OBJ file, including its associated materials, vertices, normals, and texture coordinates.

Parameters

path	{char*} The directory path where the OBJ file is located.
filename	{char*} The name of the OBJ file to be loaded.
model	{ModelData*} A pointer to a Model structure that will be populated with the loaded data.

Returns

{int} Returns 0 on success, or -1 if an error occurs during loading.

This function reads the specified OBJ file and extracts geometric data such as vertices, texture coordinates, normals, and faces. It also handles the associated materials through a corresponding MTL file, updating the Model structure accordingly. The model is dynamically allocated and resized as necessary to accommodate the loaded data.

Important Notes:

• The function relies on external utility functions such as load_mtl, find_material, malloc_obj, and close_realloc_obj for loading materials and managing dynamic memory.
• The input OBJ file must follow the standard OBJ format; otherwise, parsing may fail, leading to potential memory leaks if not handled correctly.
• Ensure that sufficient memory is available for the model structure and associated objects, as this function dynamically allocates memory for various arrays within the Model structure.

Example Usage: ModelData model; if (load_obj_model("assets/models/", "example.obj", &model) == 0) { // Successfully loaded the model } else { // Handle error }

Variable Documentation

vertex

LoadingModelBuffer::vertex

Array of vertices

Array of vertices that define the geometric points of the model.

normals

LoadingModelBuffer::normals

Array of normals

Array of normals that define the direction perpendicular to the surface of the model's faces.

textureVertex

LoadingModelBuffer::textureVertex

Array of texture vertices

Array of texture vertices that map the 2D texture coordinates to the 3D model.

faces

LoadingModelBuffer::faces

Array of faces

Array of faces that define the polygons of the model, typically triangles or quads.