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mutter/cogl/cogl-sub-texture.c
Neil Roberts ae7825275e cogl: Make CoglSubTexture only work for quad rendering 
The sub texture backend doesn't work well as a completely general
texture backend because for example when rendering with cogl_polygon
it needs to be able to tranform arbitrary texture coordinates without
reference to the other coordintes. This can't be done when the texture
coordinates are a multiple of one because sometimes the coordinate
should represent the left or top edge and sometimes it should
represent the bottom or top edge. For example if the s coordinates are
0 and 1 then 1 represents the right edge but if they are 1 and 2 then
1 represents the left edge.

Instead the sub-textures are now documented not to support coordinates
outside the range [0,1]. The coordinates for the sub-region are now
represented as integers as this helps avoid rounding issues. The
region can no longer be a super-region of the texture as this
simplifies the code quite a lot.

There are two new texture virtual functions:

transform_quad_coords_to_gl - This transforms two pairs of coordinates
     representing a quad. It will return FALSE if the coordinates can
     not be transformed. The sub texture backend uses this to detect
     coordinates that require repeating which causes cogl-primitives
     to use manual repeating.

ensure_non_quad_rendering - This is used in cogl_polygon and
     cogl_vertex_buffer to inform the texture backend that
     transform_quad_to_gl is going to be used. The atlas backend
     migrates the texture out of the atlas when it hits this.
2010-01-18 09:22:04 +00:00

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/*
* 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.
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-util.h"
#include "cogl-texture-private.h"
#include "cogl-sub-texture-private.h"
#include "cogl-context.h"
#include "cogl-handle.h"
#include "cogl-texture-driver.h"
#include <string.h>
#include <math.h>
static void _cogl_sub_texture_free (CoglSubTexture *sub_tex);
COGL_HANDLE_DEFINE (SubTexture, sub_texture);
static const CoglTextureVtable cogl_sub_texture_vtable;
static void
_cogl_sub_texture_map_range (gfloat *t1, gfloat *t2,
gint sub_offset,
gint sub_size,
gint full_size)
{
gfloat t1_frac, t1_int, t2_frac, t2_int;
t1_frac = modff (*t1, &t1_int);
t2_frac = modff (*t2, &t2_int);
if (t1_frac < 0.0f)
{
t1_frac += 1.0f;
t1_int -= 1.0f;
}
if (t2_frac < 0.0f)
{
t2_frac += 1.0f;
t2_int -= 1.0f;
}
/* If one of the coordinates is zero we need to make sure it is
still greater than the other coordinate if it was originally so
we'll flip it to the other side */
if (*t1 < *t2)
{
if (t2_frac == 0.0f)
{
t2_frac = 1.0f;
t2_int -= 1.0f;
}
}
else
{
if (t1_frac == 0.0f)
{
t1_frac = 1.0f;
t1_int -= 1.0f;
}
}
/* Convert the fractional part leaving the integer part intact */
t1_frac = (sub_offset + t1_frac * sub_size) / full_size;
*t1 = t1_frac + t1_int;
t2_frac = (sub_offset + t2_frac * sub_size) / full_size;
*t2 = t2_frac + t2_int;
}
static void
_cogl_sub_texture_map_quad (CoglSubTexture *sub_tex,
gfloat *coords)
{
guint full_width = cogl_texture_get_width (sub_tex->full_texture);
guint full_height = cogl_texture_get_height (sub_tex->full_texture);
_cogl_sub_texture_map_range (coords + 0, coords + 2,
sub_tex->sub_x, sub_tex->sub_width,
full_width);
_cogl_sub_texture_map_range (coords + 1, coords + 3,
sub_tex->sub_y, sub_tex->sub_height,
full_height);
}
/* Maps from the texture coordinates of the full texture to the
texture coordinates of the sub texture */
static gfloat
_cogl_sub_texture_unmap_coord (gfloat t,
gint sub_offset,
gint sub_size,
gint full_size)
{
gfloat frac_part, int_part;
/* Convert the fractional part leaving the integer part in tact */
frac_part = modff (t, &int_part);
if (signbit (frac_part))
frac_part = ((1.0f + frac_part) * full_size -
sub_offset - sub_size) / sub_size;
else
frac_part = (frac_part * full_size - sub_offset) / sub_size;
return frac_part + int_part;
}
static void
_cogl_sub_texture_unmap_coords (CoglSubTexture *sub_tex,
gfloat *s,
gfloat *t)
{
guint full_width = cogl_texture_get_width (sub_tex->full_texture);
guint full_height = cogl_texture_get_height (sub_tex->full_texture);
*s = _cogl_sub_texture_unmap_coord (*s, sub_tex->sub_x, sub_tex->sub_width,
full_width);
*t = _cogl_sub_texture_unmap_coord (*t, sub_tex->sub_y, sub_tex->sub_height,
full_height);
}
typedef struct _CoglSubTextureForeachData
{
CoglSubTexture *sub_tex;
CoglTextureSliceCallback callback;
void *user_data;
} CoglSubTextureForeachData;
static void
_cogl_sub_texture_foreach_cb (CoglHandle handle,
GLuint gl_handle,
GLenum gl_target,
const float *slice_coords,
const float *full_virtual_coords,
void *user_data)
{
CoglSubTextureForeachData *data = user_data;
float virtual_coords[4];
memcpy (virtual_coords, full_virtual_coords, sizeof (virtual_coords));
/* Convert the virtual coords from the full-texture space to the sub
texture space */
_cogl_sub_texture_unmap_coords (data->sub_tex,
&virtual_coords[0],
&virtual_coords[1]);
_cogl_sub_texture_unmap_coords (data->sub_tex,
&virtual_coords[2],
&virtual_coords[3]);
data->callback (handle, gl_handle, gl_target,
slice_coords, virtual_coords,
data->user_data);
}
static void
_cogl_sub_texture_manual_repeat_cb (const float *coords,
void *user_data)
{
CoglSubTextureForeachData *data = user_data;
float mapped_coords[4];
memcpy (mapped_coords, coords, sizeof (mapped_coords));
_cogl_sub_texture_map_quad (data->sub_tex, mapped_coords);
_cogl_texture_foreach_sub_texture_in_region (data->sub_tex->full_texture,
mapped_coords[0],
mapped_coords[1],
mapped_coords[2],
mapped_coords[3],
_cogl_sub_texture_foreach_cb,
user_data);
}
static void
_cogl_sub_texture_foreach_sub_texture_in_region (
CoglTexture *tex,
float virtual_tx_1,
float virtual_ty_1,
float virtual_tx_2,
float virtual_ty_2,
CoglTextureSliceCallback callback,
void *user_data)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
CoglSubTextureForeachData data;
data.sub_tex = sub_tex;
data.callback = callback;
data.user_data = user_data;
_cogl_texture_iterate_manual_repeats (_cogl_sub_texture_manual_repeat_cb,
virtual_tx_1, virtual_ty_1,
virtual_tx_2, virtual_ty_2,
&data);
}
static void
_cogl_sub_texture_set_wrap_mode_parameter (CoglTexture *tex,
GLenum wrap_mode)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
_cogl_texture_set_wrap_mode_parameter (sub_tex->full_texture, wrap_mode);
}
static void
_cogl_sub_texture_free (CoglSubTexture *sub_tex)
{
cogl_handle_unref (sub_tex->full_texture);
g_free (sub_tex);
}
CoglHandle
_cogl_sub_texture_new (CoglHandle full_texture,
gint sub_x, gint sub_y,
gint sub_width, gint sub_height)
{
CoglSubTexture *sub_tex;
CoglTexture *tex;
guint full_width, full_height;
full_width = cogl_texture_get_width (full_texture);
full_height = cogl_texture_get_width (full_texture);
/* The region must specify a non-zero subset of the full texture */
g_return_val_if_fail (sub_x >= 0 && sub_y >= 0, COGL_INVALID_HANDLE);
g_return_val_if_fail (sub_width > 0 && sub_height > 0, COGL_INVALID_HANDLE);
g_return_val_if_fail (sub_x + sub_width <= full_width, COGL_INVALID_HANDLE);
g_return_val_if_fail (sub_y + sub_height <= full_height, COGL_INVALID_HANDLE);
sub_tex = g_new (CoglSubTexture, 1);
tex = COGL_TEXTURE (sub_tex);
tex->vtable = &cogl_sub_texture_vtable;
sub_tex->full_texture = cogl_handle_ref (full_texture);
sub_tex->sub_x = sub_x;
sub_tex->sub_y = sub_y;
sub_tex->sub_width = sub_width;
sub_tex->sub_height = sub_height;
return _cogl_sub_texture_handle_new (sub_tex);
}
static gint
_cogl_sub_texture_get_max_waste (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return cogl_texture_get_max_waste (sub_tex->full_texture);
}
static gboolean
_cogl_sub_texture_is_sliced (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return cogl_texture_is_sliced (sub_tex->full_texture);
}
static gboolean
_cogl_sub_texture_can_hardware_repeat (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
/* We can hardware repeat if the subtexture actually represents all of the
of the full texture */
return (sub_tex->sub_width ==
cogl_texture_get_width (sub_tex->full_texture) &&
sub_tex->sub_height ==
cogl_texture_get_height (sub_tex->full_texture) &&
_cogl_texture_can_hardware_repeat (sub_tex->full_texture));
}
static void
_cogl_sub_texture_transform_coords_to_gl (CoglTexture *tex,
float *s,
float *t)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
/* This won't work if the sub texture is not the size of the full
texture and the coordinates are outside the range [0,1] */
*s = ((*s * sub_tex->sub_width + sub_tex->sub_x) /
cogl_texture_get_width (sub_tex->full_texture));
*t = ((*t * sub_tex->sub_height + sub_tex->sub_y) /
cogl_texture_get_height (sub_tex->full_texture));
return _cogl_texture_transform_coords_to_gl (sub_tex->full_texture, s, t);
}
static gboolean
_cogl_sub_texture_transform_quad_coords_to_gl (CoglTexture *tex,
float *coords)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
int i;
/* We can't support repeating with this method. In this case
cogl-primitives will resort to manual repeating */
for (i = 0; i < 4; i++)
if (coords[i] < 0.0f || coords[i] > 1.0f)
return FALSE;
_cogl_sub_texture_map_quad (sub_tex, coords);
_cogl_texture_transform_quad_coords_to_gl (sub_tex->full_texture, coords);
return TRUE;
}
static gboolean
_cogl_sub_texture_get_gl_texture (CoglTexture *tex,
GLuint *out_gl_handle,
GLenum *out_gl_target)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return cogl_texture_get_gl_texture (sub_tex->full_texture,
out_gl_handle,
out_gl_target);
}
static void
_cogl_sub_texture_set_filters (CoglTexture *tex,
GLenum min_filter,
GLenum mag_filter)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
_cogl_texture_set_filters (sub_tex->full_texture, min_filter, mag_filter);
}
static void
_cogl_sub_texture_ensure_mipmaps (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
_cogl_texture_ensure_mipmaps (sub_tex->full_texture);
}
static void
_cogl_sub_texture_ensure_non_quad_rendering (CoglTexture *tex)
{
}
static gboolean
_cogl_sub_texture_set_region (CoglTexture *tex,
int src_x,
int src_y,
int dst_x,
int dst_y,
unsigned int dst_width,
unsigned int dst_height,
int width,
int height,
CoglPixelFormat format,
unsigned int rowstride,
const guint8 *data)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return cogl_texture_set_region (sub_tex->full_texture,
src_x, src_y,
dst_x + sub_tex->sub_x,
dst_y + sub_tex->sub_y,
dst_width, dst_height,
width, height,
format,
rowstride,
data);
}
static void
_cogl_sub_texture_copy_region (guchar *dst,
const guchar *src,
gint dst_x, gint dst_y,
gint src_x, gint src_y,
gint width, gint height,
gint dst_rowstride,
gint src_rowstride,
gint bpp)
{
int y;
dst += dst_x * bpp + dst_y * dst_rowstride;
src += src_x * bpp + src_y * src_rowstride;
for (y = 0; y < height; y++)
{
memcpy (dst, src, bpp * width);
dst += dst_rowstride;
src += src_rowstride;
}
}
static int
_cogl_sub_texture_get_data (CoglTexture *tex,
CoglPixelFormat format,
unsigned int rowstride,
guint8 *data)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
unsigned int full_rowstride;
guint8 *full_data;
int byte_size, full_size;
gint bpp;
gint full_tex_width, full_tex_height;
/* FIXME: This gets the full data from the full texture and then
copies a subregion of that. It would be better if there was a
texture_get_sub_data virtual and it can just munge the texture
coordinates */
/* Default to internal format if none specified */
if (format == COGL_PIXEL_FORMAT_ANY)
format = cogl_texture_get_format (sub_tex->full_texture);
full_tex_width = cogl_texture_get_width (sub_tex->full_texture);
full_tex_height = cogl_texture_get_height (sub_tex->full_texture);
/* Rowstride from texture width if none specified */
bpp = _cogl_get_format_bpp (format);
if (rowstride == 0)
rowstride = sub_tex->sub_width * bpp;
/* Return byte size if only that requested */
byte_size = sub_tex->sub_height * rowstride;
if (data == NULL)
return byte_size;
full_rowstride = _cogl_get_format_bpp (format) * full_tex_width;
full_data = g_malloc (full_rowstride * full_tex_height);
full_size = cogl_texture_get_data (sub_tex->full_texture, format,
full_rowstride, full_data);
if (full_size)
_cogl_sub_texture_copy_region (data, full_data,
0, 0,
sub_tex->sub_x,
sub_tex->sub_y,
sub_tex->sub_width,
sub_tex->sub_height,
rowstride,
full_rowstride,
bpp);
else
byte_size = 0;
g_free (full_data);
return byte_size;
}
static CoglPixelFormat
_cogl_sub_texture_get_format (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return cogl_texture_get_format (sub_tex->full_texture);
}
static GLenum
_cogl_sub_texture_get_gl_format (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return _cogl_texture_get_gl_format (sub_tex->full_texture);
}
static gint
_cogl_sub_texture_get_width (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return sub_tex->sub_width;
}
static gint
_cogl_sub_texture_get_height (CoglTexture *tex)
{
CoglSubTexture *sub_tex = COGL_SUB_TEXTURE (tex);
return sub_tex->sub_height;
}
static const CoglTextureVtable
cogl_sub_texture_vtable =
{
_cogl_sub_texture_set_region,
_cogl_sub_texture_get_data,
_cogl_sub_texture_foreach_sub_texture_in_region,
_cogl_sub_texture_get_max_waste,
_cogl_sub_texture_is_sliced,
_cogl_sub_texture_can_hardware_repeat,
_cogl_sub_texture_transform_coords_to_gl,
_cogl_sub_texture_transform_quad_coords_to_gl,
_cogl_sub_texture_get_gl_texture,
_cogl_sub_texture_set_filters,
_cogl_sub_texture_ensure_mipmaps,
_cogl_sub_texture_ensure_non_quad_rendering,
_cogl_sub_texture_set_wrap_mode_parameter,
_cogl_sub_texture_get_format,
_cogl_sub_texture_get_gl_format,
_cogl_sub_texture_get_width,
_cogl_sub_texture_get_height
};
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