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);
CoglTexture2D *     cogl_texture_2d_new_from_file       (CoglContext *ctx,
                                                         const char *filename,
                                                         CoglError **error);
CoglTexture2D *     cogl_texture_2d_new_from_bitmap     (CoglBitmap *bitmap);
CoglTexture2D *     cogl_texture_2d_new_from_data       (CoglContext *ctx,
                                                         int width,
                                                         int height,
                                                         CoglPixelFormat 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);
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);

Creates a low-level CoglTexture2D texture with a given width and height that your GPU can texture from directly.

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.

The texture is still configurable until it has been allocated so for example you can influence the internal format of the texture using cogl_texture_set_components() and cogl_texture_set_premultiplied().

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

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,
                                                         CoglError **error);

Creates a low-level CoglTexture2D texture from an image file.

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.

The texture is still configurable until it has been allocated so for example you can influence the internal format of the texture using cogl_texture_set_components() and cogl_texture_set_premultiplied().

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

filename :

 the file to load

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);

Creates a low-level CoglTexture2D texture based on data residing in a CoglBitmap.

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.

The texture is still configurable until it has been allocated so for example you can influence the internal format of the texture using cogl_texture_set_components() and cogl_texture_set_premultiplied().

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

Returns :

 A newly allocated CoglTexture2D. [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,
                                                         int rowstride,
                                                         const uint8_t *data,
                                                         CoglError **error);

Creates a low-level CoglTexture2D texture based on data residing in memory.

Note

This api will always immediately allocate GPU memory for the texture and upload the given data so that the data pointer does not need to remain valid once this function returns. This means it is not possible to configure the texture before it is allocated. If you do need to configure the texture before allocation (to specify constraints on the internal format for example) then you can instead create a CoglBitmap for your data and use cogl_texture_2d_new_from_bitmap() or use cogl_texture_2d_new_with_size() and then upload data using cogl_texture_set_data()

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

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_gl_new_from_foreign ()

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

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

The texture is still configurable until it has been allocated so for example you can declare whether the texture is premultiplied with cogl_texture_set_premultiplied().

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

Returns :

 A newly allocated CoglTexture2D. [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.
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