2D textures

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

## Synopsis

                        CoglTexture2D;
    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_new_from_foreign    (CoglContext *ctx,
                                                             unsigned int gl_handle,
                                                             int width,
                                                             int height,
                                                             CoglPixelFormat format,
                                                             CoglError **error);
    CoglBool            cogl_is_texture_rectangle           (void *object);

## 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_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. [transfer full]

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. [transfer full]

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`. [transfer full]

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`. [transfer full]

Since 2.0

### cogl_texture_2d_new_from_foreign ()

    CoglTexture2D *     cogl_texture_2d_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`. [transfer full]

Since 2.0

### cogl_is_texture_rectangle ()

    CoglBool            cogl_is_texture_rectangle           (void *object);

Gets whether the given object references an existing CoglTextureRectangle object.

`object` : | A CoglObject
Returns : | `TRUE` if the object references a CoglTextureRectangle, `FALSE` otherwise.