texture

texture — Texture loading and manipulation

Synopsis


#include <g3d/texture.h>

#define             G3D_FLAG_IMG_GREYSCALE
enum                G3DTexEnv;
                    G3DImage;
G3DImage*           g3d_texture_load_cached             (G3DContext *context,
                                                         G3DModel *model,
                                                         const gchar *filename);
G3DImage*           g3d_texture_load_from_stream        (G3DContext *context,
                                                         G3DModel *model,
                                                         G3DStream *stream);
G3DImage*           g3d_texture_load                    (G3DContext *context,
                                                         const gchar *filename);
void                g3d_texture_free                    (G3DImage *texture);
gboolean            g3d_texture_prepare                 (G3DImage *texture);
gboolean            g3d_texture_flip_y                  (G3DImage *texture);
G3DImage*           g3d_texture_merge_alpha             (G3DImage *image,
                                                         G3DImage *aimage);

Description

A texture is an image used in materials. Here are some helper functions, mostly for cached loading of a G3DImage.

Details

G3D_FLAG_IMG_GREYSCALE

#define G3D_FLAG_IMG_GREYSCALE       (1L << 1)

The image just uses the red channel for grey value

enum G3DTexEnv

typedef enum {
	G3D_TEXENV_UNSPECIFIED = 0,
	G3D_TEXENV_BLEND,
	G3D_TEXENV_DECAL,
	G3D_TEXENV_MODULATE,
	G3D_TEXENV_REPLACE
} G3DTexEnv;

Specify how the texture should interact with other material properties.

`G3D_TEXENV_UNSPECIFIED`	unspecified, application decides
`G3D_TEXENV_BLEND`	use blending
`G3D_TEXENV_DECAL`	use as decal
`G3D_TEXENV_MODULATE`	use modulate
`G3D_TEXENV_REPLACE`	replace color

G3DImage

typedef struct {
	gchar *name;
	guint32 width;
	guint32 height;
	guint8 depth;
	guint32 flags;
	guint8 *pixeldata;

	guint32 tex_id;
	G3DTexEnv tex_env;
	G3DFloat tex_scale_u;
	G3DFloat tex_scale_v;
} G3DImage;

Object containing a two-dimensional pixel image.

gchar *`name`;	name of image
guint32 `width`;	width of image in pixels
guint32 `height`;	height of image in pixels
guint8 `depth`;	depth of image in bits
guint32 `flags`;	flags
guint8 *`pixeldata`;	the binary image data
guint32 `tex_id`;	the OpenGL texture id, should be unique model-wide
G3DTexEnv `tex_env`;	texture environment flags
G3DFloat `tex_scale_u`;	factor scaling texture width, should be 1.0 for most cases
G3DFloat `tex_scale_v`;	factor scaling texture height, should be 1.0 for most cases

g3d_texture_load_cached ()

G3DImage*           g3d_texture_load_cached             (G3DContext *context,
                                                         G3DModel *model,
                                                         const gchar *filename);

Loads a texture image from file and attaches it to a hash table in the model. On a second try to load this texture it is returned from cache.

`context` :	a valid context
`model` :	a valid model
`filename` :	the file name of the texture to load
Returns :	the texture image

g3d_texture_load_from_stream ()

G3DImage*           g3d_texture_load_from_stream        (G3DContext *context,
                                                         G3DModel *model,
                                                         G3DStream *stream);

Load a texture image from a stream. The file type is determined by the extension of the stream URI, so it should be valid. If model is not NULL the texture image is cached (or retrieved from cache if available).

`context` :	a valid context
`model` :	a valid model or NULL
`stream` :	an open stream
Returns :	the texture image or NULL in case of an error.

g3d_texture_load ()

G3DImage*           g3d_texture_load                    (G3DContext *context,
                                                         const gchar *filename);

Load a texture from a file. The type of file is determined by the file extension.

`context` :	a valid context
`filename` :	the file name of the texture
Returns :	the texture image or NULL in case of an error.

g3d_texture_free ()

void                g3d_texture_free                    (G3DImage *texture);

Frees all memory used by this texture image.

texture :

a texture image

g3d_texture_prepare ()

gboolean            g3d_texture_prepare                 (G3DImage *texture);

Resizes the image to dimensions which are a power of 2 to be usable as an OpenGL texture. (FIXME: unimplemented)

`texture` :	a texture image
Returns :	TRUE on success, FALSE else

g3d_texture_flip_y ()

gboolean            g3d_texture_flip_y                  (G3DImage *texture);

Mirror the image along the x axis - all y coordinates are inverted.

`texture` :	a texture image
Returns :	TRUE on success, FALSE on error.

g3d_texture_merge_alpha ()

G3DImage*           g3d_texture_merge_alpha             (G3DImage *image,
                                                         G3DImage *aimage);

Merges alpha information from aimage into output image. If image is NULL a new image is created, else image is returned with alpha from aimage.

`image` :	a texture image or NULL
`aimage` :	an image with alpha information
Returns :	a texture image or NULL in case of an error.

			libg3d Reference Manual
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