mutter/cogl/cogl-sub-texture-private.h
Neil Roberts 8119c184da cogl-sub-texture: Optimise taking a sub texture of a sub texture
When creating a Cogl sub-texture, if the full texture is also a sub
texture it will now just offset the x and y and reference the full
texture instead. This avoids one level of indirection when rendering
the texture which reduces the chances of getting rounding errors in
the calculations.
2010-02-12 16:57:17 +00:00

71 lines
2.3 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2009 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifndef __COGL_SUB_TEXTURE_H
#define __COGL_SUB_TEXTURE_H
#include "cogl-handle.h"
#include "cogl-texture-private.h"
#define COGL_SUB_TEXTURE(tex) ((CoglSubTexture *) tex)
typedef struct _CoglSubTexture CoglSubTexture;
struct _CoglSubTexture
{
CoglTexture _parent;
/* This is the texture that was passed in to
_cogl_sub_texture_new. If this is also a sub texture then we will
use the full texture from that to render instead of making a
chain. However we want to preserve the next texture in case the
user is expecting us to keep a reference and also so that we can
later add a cogl_sub_texture_get_full_texture() function. */
CoglHandle next_texture;
/* This is the texture that will actually be used to draw. It will
point to the end of the chain if a sub texture of a sub texture
is created */
CoglHandle full_texture;
/* The region represented by this sub-texture. This is the region of
full_texture which won't necessarily be the same as the region
passed to _cogl_sub_texture_new if next_texture is actually
already a sub texture */
int sub_x;
int sub_y;
int sub_width;
int sub_height;
};
GQuark
_cogl_handle_sub_texture_get_type (void);
CoglHandle
_cogl_sub_texture_new (CoglHandle next_texture,
int sub_x,
int sub_y,
int sub_width,
int sub_height);
#endif /* __COGL_SUB_TEXTURE_H */