lg_mesh.c File Reference

Functions
LG_Mesh *	lg_load_vbo (const char *path, zboolean force_reload_obj, zboolean invert_z, zboolean do_normalize_xyz, zboolean do_horiz_center, zboolean do_vert_center, zboolean do_vert_bottom)
LG_Mesh *	lg_mesh_new_from_objfile (const char *path, zboolean invert_z, zboolean do_normalize_xyz, zboolean do_horiz_center, zboolean do_vert_center, zboolean do_vert_bottom)
LG_Mesh *	lg_mesh_new_from_fbxfile (const char *path, zboolean invert_z, zboolean do_normalize_xyz, zboolean do_horiz_center, zboolean do_vert_center, zboolean do_vert_bottom)
void	lg_mesh_free (LG_Mesh *mesh)
void	lg_mesh_info (LG_Mesh *mesh)
int	lg_obj_file_save_to_cache (void *asset_buf, const char *file_name, size_t size, size_t *written_size)
void *	lg_obj_file_open_from_cache (const char *file_name)
int	lg_vbo_save_to_file (const char *path, LG_Mesh *mesh)
int	lg_vbo_load_from_file (const char *path, LG_Mesh **mesh)
int	lg_mesh_reload_mats (LG_Mesh *mesh)

Detailed Description

This module deals with meshes, ie data that will feed VBOs and IBOs for fast and efficient drawing.

=== MESHES MUST BE PURE-TRIANGULAR ===

 Using MeshLab filters:
    remeshing, simplification and reconstruction
            turn into a pure-triangle mesh
 Also:
    normals, curvatures and orientation
            transform: translate, center, set origin
                    -> center on layer bbox
    normals, curvatures and orientation
            transform: scale, normalize
                    -> scale to unit bbox

At the moment, read only a limited set of data from WAVEFRONT OBJ files: vertex/index values for v (coords), vt (texture coords), vn (normals), f (triangular faces), mtllib, usemtl (materials/textures stuff), plus newmtl, and map_K* (in MTL files).

Will create a Vertex_uv_n VBO (see lg_vertex.h).

You can/should only use this func to load meshes:

 LG_Mesh *lg_load_vbo(const char *path, zboolean force_reload_obj, zboolean do_normalize_xyz, zboolean do_horiz_center, zboolean do_vert_center)

and you can/should only use this func when done with a mesh:

 void       lg_mesh_free(LG_Mesh *)

and just ignore the details.

(Use everything here only if you know what you're doing).

Function Documentation

lg_load_vbo()

LG_Mesh* lg_load_vbo	(	const char *	path,
		zboolean	force_reload_obj,
		zboolean	invert_z,
		zboolean	do_normalize_xyz,
		zboolean	do_horiz_center,
		zboolean	do_vert_center,
		zboolean	do_vert_bottom
	)

Load VBO &co

=== This is the entry point for loading meshes (obj, vbo, ibo) ===

---

THIS WHOLE MODULE WORKS GREAT BUT NEED TO FIND LESS CONFUSING FUNCS NAMES AND IMPROVE DOC

We use a cache mechanism:

• Try first to load the mesh data (VBO, IBO, and info) from cache, unless force_reload_obj is set
• If it doesn't exist, load and parse the obj file, then save it to cache

All mesh data is saved

On Android, obj files are cached as well

-> Should use:

• env->app_wr_dir
• env->assets_dir
• env->vbo_cache
• env->obj_cache
• lg_assets_file()
• lg_mesh()

Refactoring the I/O API -> assets dir and writable dir ? lg_io.c/h ? No, probably just need to better doc everything

Parameters

path	Path to OBJ file
force_reload_obj	Force (re)loading and (re)parsing the OBJ file
invert_z	Invert z spatial coord - should be set to TRUE if mesh uses RH coords sys, FALSE if mesh uses LH coords sys
do_normalize_xyz
do_horiz_center
do_vert_center	Center mesh vertically, if do_vert_bottom is not set
do_vert_bottom	Set mesh origin vertically at bottom, override do_vert_center

Returns

A LG_Mesh instance if OK, NULL on error

lg_mesh_new_from_objfile()

LG_Mesh* lg_mesh_new_from_objfile	(	const char *	path,
		zboolean	invert_z,
		zboolean	do_normalize_xyz,
		zboolean	do_horiz_center,
		zboolean	do_vert_center,
		zboolean	do_vert_bottom
	)

Create mesh from obj file

Parameters

path	OBJ file name
invert_z	Invert z spatial coord - should be set to TRUE if mesh uses RH coords sys, FALSE if mesh uses LH coords sys
do_normalize_xyz	Normalize spatial coords
do_horiz_center	Center mesh horizontally
do_vert_center	Center mesh vertically, if do_vert_bottom is not set
do_vert_bottom	Set mesh origin vertically at bottom, override do_vert_center

Returns

A new LG_Mesh instance if OK, NULL on error

lg_mesh_new_from_fbxfile()

LG_Mesh* lg_mesh_new_from_fbxfile	(	const char *	path,
		zboolean	invert_z,
		zboolean	do_normalize_xyz,
		zboolean	do_horiz_center,
		zboolean	do_vert_center,
		zboolean	do_vert_bottom
	)

Create mesh from fbx file

Parameters

path	FBX file name
invert_z	Invert z spatial coord - should be set to TRUE if mesh uses RH coords sys, FALSE if mesh uses LH coords sys
do_normalize_xyz	Normalize spatial coords
do_horiz_center	Center mesh horizontally
do_vert_center	Center mesh vertically, if do_vert_bottom is not set
do_vert_bottom	Set mesh origin vertically at bottom, override do_vert_center

Returns

A new LG_Mesh instance if OK, NULL on error

lg_mesh_free()

void lg_mesh_free

(

LG_Mesh *

mesh

)

Free mesh

Parameters

mesh

lg_mesh_info()

void lg_mesh_info

(

LG_Mesh *

mesh

)

Print out LG_Mesh info

Parameters

mesh

lg_obj_file_save_to_cache()

int lg_obj_file_save_to_cache	(	void *	asset_buf,
		const char *	file_name,
		size_t	size,
		size_t *	written_size
	)

Save obj file to cache

Parameters

asset_buf	?
file_name	?
size	?
written_size	?

Returns

LG_OK if OK, error code otherwise

lg_obj_file_open_from_cache()

void* lg_obj_file_open_from_cache

(

const char *

file_name

)

Load obj file from cache

Parameters

file_name

The OBJ file name

Returns

Opened stream if OK, NULL on error

lg_vbo_save_to_file()

int lg_vbo_save_to_file	(	const char *	path,
		LG_Mesh *	mesh
	)

Actually save mesh with VBO and IBO in binary form, so should find a more accurate name. Don't add suffix LG_MESH_INFO_EXT, LG_MESH_VBO_EXT, LG_MESH_IBO_EXT to path, it's done automagically. Only the basename of path is used. All binary files are saved in the cache.

Parameters

path	Path to OBJ file
mesh	Pointer to a LG_Mesh

Returns

LG_OK if OK, error code otherwise

lg_vbo_load_from_file()

int lg_vbo_load_from_file	(	const char *	path,
		LG_Mesh **	mesh
	)

Same as above but for reading binary files

Parameters

path	Path to OBJ file
mesh	Pointer to an array of pointers to LG_Mesh

Returns

LG_OK if OK, error code otherwise

lg_mesh_reload_mats()

int lg_mesh_reload_mats

(

LG_Mesh *

mesh

)

Reload materials textures correctly, when mesh is loaded from cache

Parameters

mesh	Pointer to a LG_Mesh

Returns

LG_OK if OK, error code otherwise