Function

Coglmeta_texture_foreach_in_region

Declaration [src] 

void
cogl_meta_texture_foreach_in_region (
  CoglTexture* texture,
  float tx_1,
  float ty_1,
  float tx_2,
  float ty_2,
  CoglPipelineWrapMode wrap_s,
  CoglPipelineWrapMode wrap_t,
  CoglMetaTextureCallback callback,
  void* user_data
)

Description [src]

Allows you to manually iterate the low-level textures that define a given region of a high-level CoglMetaTexture.

For example cogl_texture_2d_sliced_new_with_size() can be used to create a meta texture that may slice a large image into multiple, smaller power-of-two sized textures. These high level textures are not directly understood by a GPU and so this API must be used to manually resolve the underlying textures for drawing.

All high level textures (CoglAtlasTexture, CoglSubTexture, CoglTexturePixmapX11, and CoglTexture2DSliced) can be handled consistently using this interface which greately simplifies implementing primitives that support all texture types.

For example if you use the cogl_rectangle() API then Cogl will internally use this API to resolve the low level textures of any meta textures you have associated with CoglPipeline layers.

The low level drawing APIs such as cogl_primitive_draw() don’t understand the CoglMetaTexture interface and so it is your responsibility to use this API to resolve all CoglPipeline textures into low-level textures before drawing.

For each low-level texture that makes up part of the given region of the meta_texture, callback is called specifying how the low-level texture maps to the original region.

Parameters

texture

Type: CoglTexture

An object implementing the CoglMetaTexture interface.

The data is owned by the caller of the function.
tx_1

Type: float

The top-left x coordinate of the region to iterate.

ty_1

Type: float

The top-left y coordinate of the region to iterate.

tx_2

Type: float

The bottom-right x coordinate of the region to iterate.

ty_2

Type: float

The bottom-right y coordinate of the region to iterate.

wrap_s

Type: CoglPipelineWrapMode

The wrap mode for the x-axis.

wrap_t

Type: CoglPipelineWrapMode

The wrap mode for the y-axis.

callback

Type: CoglMetaTextureCallback

A CoglMetaTextureCallback pointer to be called for each low-level texture within the specified region.

user_data

Type: void*

A private pointer that is passed to callback.

The argument can be NULL.
The data is owned by the caller of the function.