2D textures

2D textures — Functions for creating and manipulating 2D textures

Synopsis

                    CoglTexture2D;
CoglBool            cogl_is_texture_2d                  (void *object);

CoglTexture2D *     cogl_texture_2d_new_with_size       (CoglContext *ctx,
                                                         int width,
                                                         int height,
                                                         CoglPixelFormat internal_format);
CoglTexture2D *     cogl_texture_2d_new_from_file       (CoglContext *ctx,
                                                         const char *filename,
                                                         CoglPixelFormat internal_format,
                                                         CoglError **error);
CoglTexture2D *     cogl_texture_2d_new_from_bitmap     (CoglBitmap *bitmap,
                                                         CoglPixelFormat internal_format,
                                                         CoglError **error);
CoglTexture2D *     cogl_texture_2d_new_from_data       (CoglContext *ctx,
                                                         int width,
                                                         int height,
                                                         CoglPixelFormat format,
                                                         CoglPixelFormat internal_format,
                                                         int rowstride,
                                                         const uint8_t *data,
                                                         CoglError **error);
CoglTexture2D *     cogl_texture_2d_gl_new_from_foreign (CoglContext *ctx,
                                                         unsigned int gl_handle,
                                                         int width,
                                                         int height,
                                                         CoglPixelFormat format,
                                                         CoglError **error);

Description

These functions allow low-level 2D textures to be allocated. These differ from sliced textures for example which may internally be made up of multiple 2D textures, or atlas textures where Cogl must internally modify user texture coordinates before they can be used by the GPU.

You should be aware that many GPUs only support power of two sizes for CoglTexture2D textures. You can check support for non power of two textures by checking for the COGL_FEATURE_ID_TEXTURE_NPOT feature via cogl_has_feature().

Details

CoglTexture2D

typedef struct _CoglTexture2D CoglTexture2D;

cogl_is_texture_2d ()

CoglBool            cogl_is_texture_2d                  (void *object);

Gets whether the given object references an existing CoglTexture2D object.

object :

A CoglObject

Returns :

TRUE if the object references a CoglTexture2D, FALSE otherwise

cogl_texture_2d_new_with_size ()

CoglTexture2D *     cogl_texture_2d_new_with_size       (CoglContext *ctx,
                                                         int width,
                                                         int height,
                                                         CoglPixelFormat internal_format);

Allocates a low-level CoglTexture2D texture that your GPU can texture from directly. This is unlike sliced textures for example which may be comprised of multiple internal textures, or atlas textures where Cogl has to modify texture coordinates before they may be used by the GPU.

The storage for the texture is not allocated before this function returns. You can call cogl_texture_allocate() to explicitly allocate the underlying storage or preferably let Cogl automatically allocate storage lazily when it may know more about how the texture is being used and can optimize how it is allocated.

Note

Many GPUs only support power of two sizes for CoglTexture2D textures. You can check support for non power of two textures by checking for the COGL_FEATURE_ID_TEXTURE_NPOT feature via cogl_has_feature().

ctx :

A CoglContext

width :

Width of the texture to allocate

height :

Height of the texture to allocate

internal_format :

The format of the texture

Returns :

A new CoglTexture2D object with no storage yet allocated.

Since 2.0


cogl_texture_2d_new_from_file ()

CoglTexture2D *     cogl_texture_2d_new_from_file       (CoglContext *ctx,
                                                         const char *filename,
                                                         CoglPixelFormat internal_format,
                                                         CoglError **error);

Creates a CoglTexture2D from an image file.

ctx :

A CoglContext

filename :

the file to load

internal_format :

the CoglPixelFormat to use for the GPU storage of the texture. If COGL_PIXEL_FORMAT_ANY is given then a premultiplied format similar to the format of the source data will be used. The default blending equations of Cogl expect premultiplied color data; the main use of passing a non-premultiplied format here is if you have non-premultiplied source data and are going to adjust the blend mode (see cogl_material_set_blend()) or use the data for something other than straight blending.

error :

A CoglError to catch exceptional errors or NULL

Returns :

A newly created CoglTexture2D or NULL on failure and error will be updated.

Since 1.16


cogl_texture_2d_new_from_bitmap ()

CoglTexture2D *     cogl_texture_2d_new_from_bitmap     (CoglBitmap *bitmap,
                                                         CoglPixelFormat internal_format,
                                                         CoglError **error);

Creates a new CoglTexture2D texture based on data residing in a bitmap. These are unlike sliced textures for example which may be comprised of multiple internal textures, or atlas textures where Cogl has to modify texture coordinates before they may be used by the GPU.

Note

Many GPUs only support power of two sizes for CoglTexture2D textures. You can check support for non power of two textures by checking for the COGL_FEATURE_ID_TEXTURE_NPOT feature via cogl_has_feature().

bitmap :

A CoglBitmap

internal_format :

the CoglPixelFormat that will be used for storing the buffer on the GPU. If COGL_PIXEL_FORMAT_ANY is given then a premultiplied format similar to the format of the source data will be used. The default blending equations of Cogl expect premultiplied color data; the main use of passing a non-premultiplied format here is if you have non-premultiplied source data and are going to adjust the blend mode (see cogl_pipeline_set_blend()) or use the data for something other than straight blending.

error :

A CoglError for exceptions

Returns :

A newly allocated CoglTexture2D, or if the size is not supported (because it is too large or a non-power-of-two size that the hardware doesn't support) it will return NULL and set error.

Since 2.0

Stability Level: Unstable


cogl_texture_2d_new_from_data ()

CoglTexture2D *     cogl_texture_2d_new_from_data       (CoglContext *ctx,
                                                         int width,
                                                         int height,
                                                         CoglPixelFormat format,
                                                         CoglPixelFormat internal_format,
                                                         int rowstride,
                                                         const uint8_t *data,
                                                         CoglError **error);

Creates a new CoglTexture2D texture based on data residing in memory. These are unlike sliced textures for example which may be comprised of multiple internal textures, or atlas textures where Cogl has to modify texture coordinates before they may be used by the GPU.

Note

Many GPUs only support power of two sizes for CoglTexture2D textures. You can check support for non power of two textures by checking for the COGL_FEATURE_ID_TEXTURE_NPOT feature via cogl_has_feature().

ctx :

A CoglContext

width :

width of texture in pixels

height :

height of texture in pixels

format :

the CoglPixelFormat the buffer is stored in in RAM

internal_format :

the CoglPixelFormat that will be used for storing the buffer on the GPU. If COGL_PIXEL_FORMAT_ANY is given then a premultiplied format similar to the format of the source data will be used. The default blending equations of Cogl expect premultiplied color data; the main use of passing a non-premultiplied format here is if you have non-premultiplied source data and are going to adjust the blend mode (see cogl_pipeline_set_blend()) or use the data for something other than straight blending.

rowstride :

the memory offset in bytes between the starts of scanlines in data. A value of 0 will make Cogl automatically calculate rowstride from width and format.

data :

pointer the memory region where the source buffer resides

error :

A CoglError for exceptions

Returns :

A newly allocated CoglTexture2D, or if the size is not supported (because it is too large or a non-power-of-two size that the hardware doesn't support) it will return NULL and set error.

Since 2.0


cogl_texture_2d_gl_new_from_foreign ()

CoglTexture2D *     cogl_texture_2d_gl_new_from_foreign (CoglContext *ctx,
                                                         unsigned int gl_handle,
                                                         int width,
                                                         int height,
                                                         CoglPixelFormat format,
                                                         CoglError **error);

Wraps an existing GL_TEXTURE_2D texture object as a CoglTexture2D. This can be used for integrating Cogl with software using OpenGL directly.

Note

The results are undefined for passing an invalid gl_handle or if width or height don't have the correct texture geometry.

ctx :

A CoglContext

gl_handle :

A GL handle for a GL_TEXTURE_2D texture object

width :

Width of the foreign GL texture

height :

Height of the foreign GL texture

format :

The format of the texture

error :

A CoglError for exceptions

Returns :

A newly allocated CoglTexture2D, or if Cogl could not validate the gl_handle in some way (perhaps because of an unsupported format) it will return NULL and set error.

Since 2.0