lg_textures.c File Reference

Functions
void	lg_init_textures_module ()
LG_Texture *	lg_texture_new_from_data (lg_tc_format tc_format, int tex_type, const char *path, void *data, void **cubemap_data, size_t size, int w, int h, int n_mipmaps)
LG_Texture *	lg_texture_new_from_file (int tex_type, const char *path)
SDL_Surface *	lg_sdl_surf_from_file (const char *path, int scale_x, int scale_y)
void *	lg_compressed_texdata_from_file (const char *path, lg_tc_format *tc_format, size_t *size, int *w, int *h, int *n_mipmaps)
zboolean	lg_test_file_extension (const char *path, const char *ext)
int	lg_get_png_dims (const char *path, int *w, int *h)
void	lg_texture_remove (LG_Texture *node)
void	lg_texture_remove_all ()
LG_Texture *	lg_texture_first (LG_Texture *node)
LG_Texture *	lg_texture_last (LG_Texture *node)
LG_Texture *	lg_texture_find_by_id (GLuint id)
int	lg_texture_count_nodes ()
void	lg_texture_info (const LG_Texture *tex)
void	lg_texture_info_all ()
void	lg_texture_list_all ()
zboolean	lg_read_pixels_from_screen (void *pixels, Rec2Di r)
zboolean	lg_write_pixels_to_screen (void *pixels, const Rec2Di *dest)
void	lg_texture_unbind (LG_Texture *tex)
void	lg_tex_units_info ()
unsigned int	lg_get_active_tex ()
void	lg_active_tex_info ()
void	lg_free_sdl_surf (SDL_Surface *surf)
int	lg_surf_depth (SDL_Surface *surf)
void	lg_info_out_read_framebuffer ()

Detailed Description

=== Handle all texture related stuff ===

We're using a global doubly-linked list.

Vars storing the texture list and the assigned tex units:

• static LG_Texture *node = &node0 in lg_env_instance.c, accessed with lg_get_texture_list()
• static zboolean assigned_tex_unit[LG_MAX_TEX_UNITS]

These vars are for all libgame and app textures, and are updated by all funcs creating or removing textures.

They are 'private', there is no public API, apart from lg_get_texture_list().

So, you can/should only use this func to create new textures:

 LG_Texture *lg_texture_new_from_file(int tex_type, const char *path)

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

 void lg_texture_remove(LG_Texture *node)

and just ignore the details.

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

*** WARNING: Rendering of DXT1/3 textures with mipmaps is still f**ked up at the moment, so avoid them until it's fixed ***

Function Documentation

lg_init_textures_module()

void lg_init_textures_module

(

)

Must be called at init time in libgame.c

lg_texture_new_from_data()

LG_Texture* lg_texture_new_from_data	(	lg_tc_format	tc_format,
		int	tex_type,
		const char *	path,
		void *	data,
		void **	cubemap_data,
		size_t	size,
		int	w,
		int	h,
		int	n_mipmaps
	)

Create a new LG_Texture node from data (either a SDL_Surface or compressed tex data), and ADD IT to the global doubly-linked list

(Completely replace SDL_CreateTextureFromSurface())

Now also reading compressed textures - see lg_dds_loader.c/h

About mipmaps:

• They are ignored in uncompressed textures, as they are generated with glGenerateMipmap(GL_TEXTURE_2D)
• Skyboxes dont need/want mipmaps, so they also are ignored, if included
• *** WARNING: Rendering of DXT1/3 textures with mipmaps is still f**ked up at the moment, so avoid them until it's fixed ***

Parameters

tc_format	If tc_format == LG_TC_UNCOMPRESSED, data is a SDL_Surface, otherwise data is compressed texture data
tex_type	GL_TEXTURE_2D or GL_TEXTURE_CUBE_MAP
path	Path to image file, only used at this point to store info
data	A pointer to compressed texture data or a SDL_Surface - ignored if tex_type == GL_TEXTURE_CUBE_MAP
cubemap_data	Array of 6 compressed tex data or 6 SDL_Surface's - ignored if tex_type == GL_TEXTURE_2D
size	Size - ignored if texture is not compressed
w	Width
h	Height
n_mipmaps	Number of generated mipmaps - WARNING: original image is considered mipmap level 0, so n_mipmaps must be at least 1

Returns

A LG_Texture if OK or NULL on error

lg_texture_new_from_file()

LG_Texture* lg_texture_new_from_file	(	int	tex_type,
		const char *	path
	)

Create a new LG_Texture node from a file and ADD IT to the global doubly-linked list

=== You should use this func when creating new textures ===

*** WARNING #1: Rendering of DXT1/3 textures with mipmaps is still f**ked up at the moment, so avoid them until it's fixed ***

*** WARNING #2: stbi_info() doesn't work on Android - used (only) to get jpg file dims, so avoid them until (?) ***

(Seems stb_image is f**ked up on Android and pretty useless, should probably get rid of it)

Parameters

tex_type	GL_TEXTURE_2D or GL_TEXTURE_CUBE_MAP
path	Path to image file

Returns

A LG_Texture if OK, NULL on error

lg_sdl_surf_from_file()

SDL_Surface* lg_sdl_surf_from_file	(	const char *	path,
		int	scale_x,
		int	scale_y
	)

For image and NON-compressed tex files

NO scaling is applied if scale_x == 0 or scale_y == 0

Otherwise, scale_x/y apply to env->top_win_logical_w/h, ie

• w = env->top_win_logical_w * scale_x
• h = env->top_win_logical_h * scale_y

Parameters

path	Path to image file
scale_x
scale_y

Returns

A SDL_Surface if OK, NULL on error

lg_compressed_texdata_from_file()

void* lg_compressed_texdata_from_file	(	const char *	path,
		lg_tc_format *	tc_format,
		size_t *	size,
		int *	w,
		int *	h,
		int *	n_mipmaps
	)

For compressed tex files

Supported file formats and texture compression formats:

• S3TC -> DDS with DXT1 and DXT3 tex compression (Linux only)
• ASCT
• PKM with ETC1 tex compression
• *** WARNING: Rendering of DXT1/3 textures with mipmaps is still f**ked up at the moment, so avoid them until it's fixed ***

Returned data must be freed afterwards

Parameters

path	Path to compressed tex file
tc_format	Pointer to lg_tc_format
size	Pointer to size
w	Pointer to width
h	Pointer to height
n_mipmaps	Pointer n_mipmaps

Returns

Pointer to compressed data if OK, NULL on error

lg_test_file_extension()

zboolean lg_test_file_extension	(	const char *	path,
		const char *	ext
	)

Test path against file extension (case-insensitive strings comparaison)

NOTE: doesn't search backward for '.' but uses extension string length instead, so extension should include '.', ie ".png", not "png"

Parameters

path	Path
ext	File extension to test against (ie ".png", ".jpg", etc)

Returns

TRUE if path file extension == ext, FALSE otherwise

lg_get_png_dims()

int lg_get_png_dims	(	const char *	path,
		int *	w,
		int *	h
	)

Get PNG image dimensions

Parameters

path	Path
w	Width
h	Height

Returns

LG_OK if OK

lg_texture_remove()

void lg_texture_remove

(

LG_Texture *

node

)

Remove node from list AND free associated resources

=== You should use this func when done with a texture ===

Parameters

node	A LG_Texture node

lg_texture_remove_all()

void lg_texture_remove_all

(

)

Remove all nodes (but <node0>) from list, freeing all resources

lg_texture_first()

LG_Texture* lg_texture_first

(

LG_Texture *

node

)

Return first node

Parameters

node	A LG_Texture node

Returns

First node of the list

lg_texture_last()

LG_Texture* lg_texture_last

(

LG_Texture *

node

)

Return last node

Parameters

node	A LG_Texture node

Returns

Last node of the list

lg_texture_find_by_id()

LG_Texture* lg_texture_find_by_id

(

GLuint

id

)

Return first found occurence

Parameters

id	A LG_Texture id

Returns

Found LG_Texture node or NULL if not found

lg_texture_count_nodes()

int lg_texture_count_nodes

(

)

Count all nodes

Returns

Number of nodes of the list

lg_texture_info()

void lg_texture_info

(

const LG_Texture *

tex

)

Print out texture info

Parameters

tex	A LG_Texture

lg_texture_info_all()

void lg_texture_info_all

(

)

Print out texture info for all nodes

lg_texture_list_all()

void lg_texture_list_all

(

)

Print out a list of all textures (id and path)

lg_read_pixels_from_screen()

zboolean lg_read_pixels_from_screen	(	void *	pixels,
		Rec2Di	r
	)

Store a v-flipped image (don't ask me why it's v-flipped)

From some doc somewhere: "Only two format/type parameter pairs are accepted. GL_RGBA/GL_UNSIGNED_BYTE is always accepted, and the other acceptable pair can be discovered by querying GL_IMPLEMENTATION_COLOR_READ_FORMAT and GL_IMPLEMENTATION_COLOR_READ_TYPE."

Parameters

pixels	A pixel buffer
r	A Rec2Di

Returns

TRUE if OK

lg_write_pixels_to_screen()

zboolean lg_write_pixels_to_screen	(	void *	pixels,
		const Rec2Di *	dest
	)

'Un-flip' the image provided by lg_read_pixels_from_screen()

If NULL, dest is the entire rendering target

Parameters

pixels	A pixel buffer
dest	A Rec2Di

Returns

TRUE if OK

lg_texture_unbind()

void lg_texture_unbind

(

LG_Texture *

tex

)

Unbind texture

lg_tex_units_info()

void lg_tex_units_info

(

)

Print out texture units info

lg_get_active_tex()

unsigned int lg_get_active_tex

(

)

Returns

The active texture unit

lg_active_tex_info()

void lg_active_tex_info

(

)

Print out active texture unit info

lg_free_sdl_surf()

void lg_free_sdl_surf

(

SDL_Surface *

surf

)

Free SDL_Surface if not NULL

Parameters

surf	Addr of SDL_Surface

lg_surf_depth()

int lg_surf_depth

(

SDL_Surface *

surf

)

Surface depth of a SDL_Surface

Parameters

surf	Addr of SDL_Surface

Returns

Surface depth

lg_info_out_read_framebuffer()

void lg_info_out_read_framebuffer

(

)

Print out current bound read framebuffer info