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mutter/cogl/cogl-texture.c
Neil Roberts e20c98e548 cogl: Let GL do the format conversion when uploading texture data 
Cogl accepts a pixel format for both the data in memory and the
internal format to be used for the texture. If they do not match then
it would convert them using the CoglBitmap functions before uploading
the data. However, GL also lets you specify both formats so it makes
more sense to let GL do the conversion. The driver may need the
texture in a specific format so it may end up being converted anyway.

The cogl_texture_upload_data functions have been removed and replaced
with a single function to prepare the bitmap. This will only do the
premultiplication conversion because that is the only part that GL
can't do directly.
2010-02-01 13:27:34 +00:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 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:
* Matthew Allum <mallum@openedhand.com>
* Neil Roberts <neil@linux.intel.com>
* Robert Bragg <robert@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-util.h"
#include "cogl-bitmap.h"
#include "cogl-bitmap-private.h"
#include "cogl-texture-private.h"
#include "cogl-texture-driver.h"
#include "cogl-texture-2d-sliced-private.h"
#include "cogl-texture-2d-private.h"
#include "cogl-sub-texture-private.h"
#include "cogl-atlas-texture-private.h"
#include "cogl-material.h"
#include "cogl-context.h"
#include "cogl-handle.h"
#include "cogl-primitives.h"
#include "cogl-framebuffer-private.h"
#include <string.h>
#include <stdlib.h>
#include <math.h>
/* XXX:
* The CoglHandle macros don't support any form of inheritance, so for
* now we implement the CoglHandle support for the CoglTexture
* abstract class manually.
*/
gboolean
cogl_is_texture (CoglHandle handle)
{
CoglHandleObject *obj = (CoglHandleObject *)handle;
if (handle == COGL_INVALID_HANDLE)
return FALSE;
return (obj->klass->type == _cogl_handle_texture_2d_get_type () ||
obj->klass->type == _cogl_handle_atlas_texture_get_type () ||
obj->klass->type == _cogl_handle_texture_2d_sliced_get_type () ||
obj->klass->type == _cogl_handle_sub_texture_get_type ());
}
CoglHandle
cogl_texture_ref (CoglHandle handle)
{
if (!cogl_is_texture (handle))
return COGL_INVALID_HANDLE;
_COGL_HANDLE_DEBUG_REF (CoglTexture, handle);
cogl_handle_ref (handle);
return handle;
}
void
cogl_texture_unref (CoglHandle handle)
{
if (!cogl_is_texture (handle))
{
g_warning (G_STRINGIFY (cogl_texture_unref)
": Ignoring unref of Cogl handle "
"due to type mismatch");
return;
}
_COGL_HANDLE_DEBUG_UNREF (CoglTexture, handle);
cogl_handle_unref (handle);
}
gboolean
_cogl_texture_prepare_for_upload (CoglBitmap *src_bmp,
CoglPixelFormat dst_format,
CoglPixelFormat *dst_format_out,
CoglBitmap *dst_bmp,
gboolean *copied_bitmap,
GLenum *out_glintformat,
GLenum *out_glformat,
GLenum *out_gltype)
{
/* If the application hasn't specified a specific format then we'll
* pick the most appropriate. By default Cogl will use a
* premultiplied internal format. Later we will add control over
* this. */
if (dst_format == COGL_PIXEL_FORMAT_ANY)
{
if ((src_bmp->format & COGL_A_BIT) &&
src_bmp->format != COGL_PIXEL_FORMAT_A_8)
dst_format = src_bmp->format | COGL_PREMULT_BIT;
else
dst_format = src_bmp->format;
}
if (dst_bmp)
{
*copied_bitmap = FALSE;
*dst_bmp = *src_bmp;
/* If the source format does not have the same premult flag as the
dst format then we need to copy and convert it */
if ((src_bmp->format & COGL_A_BIT) &&
src_bmp->format != COGL_PIXEL_FORMAT_A_8 &&
(src_bmp->format & COGL_PREMULT_BIT) !=
(dst_format & COGL_PREMULT_BIT))
{
dst_bmp->data = g_memdup (dst_bmp->data,
dst_bmp->height * dst_bmp->rowstride);
*copied_bitmap = TRUE;
if (!_cogl_bitmap_convert_premult_status (dst_bmp,
src_bmp->format ^
COGL_PREMULT_BIT))
{
g_free (dst_bmp->data);
return FALSE;
}
}
}
/* Use the source format from the src bitmap type and the internal
format from the dst format type so that GL can do the
conversion */
_cogl_pixel_format_to_gl (src_bmp->format,
NULL, /* internal format */
out_glformat,
out_gltype);
_cogl_pixel_format_to_gl (dst_format,
out_glintformat,
NULL,
NULL);
if (dst_format_out)
*dst_format_out = dst_format;
return TRUE;
}
void
_cogl_texture_prep_gl_alignment_for_pixels_upload (int pixels_rowstride)
{
if (!(pixels_rowstride & 0x7))
GE( glPixelStorei (GL_UNPACK_ALIGNMENT, 8) );
else if (!(pixels_rowstride & 0x3))
GE( glPixelStorei (GL_UNPACK_ALIGNMENT, 4) );
else if (!(pixels_rowstride & 0x1))
GE( glPixelStorei (GL_UNPACK_ALIGNMENT, 2) );
else
GE( glPixelStorei (GL_UNPACK_ALIGNMENT, 1) );
}
void
_cogl_texture_prep_gl_alignment_for_pixels_download (int pixels_rowstride)
{
if (!(pixels_rowstride & 0x7))
GE( glPixelStorei (GL_PACK_ALIGNMENT, 8) );
else if (!(pixels_rowstride & 0x3))
GE( glPixelStorei (GL_PACK_ALIGNMENT, 4) );
else if (!(pixels_rowstride & 0x1))
GE( glPixelStorei (GL_PACK_ALIGNMENT, 2) );
else
GE( glPixelStorei (GL_PACK_ALIGNMENT, 1) );
}
/* FIXME: wrap modes should be set on materials not textures */
void
_cogl_texture_set_wrap_mode_parameter (CoglHandle handle,
GLenum wrap_mode)
{
CoglTexture *tex = COGL_TEXTURE (handle);
tex->vtable->set_wrap_mode_parameter (tex, wrap_mode);
}
/* This is like CoglSpanIter except it deals with floats and it
effectively assumes there is only one span from 0.0 to 1.0 */
typedef struct _CoglTextureIter
{
gfloat pos, end, next_pos;
gboolean flipped;
gfloat t_1, t_2;
} CoglTextureIter;
static void
_cogl_texture_iter_update (CoglTextureIter *iter)
{
gfloat t_2;
float frac_part;
frac_part = modff (iter->pos, &iter->next_pos);
/* modff rounds the int part towards zero so we need to add one if
we're meant to be heading away from zero */
if (iter->pos >= 0.0f || frac_part == 0.0f)
iter->next_pos += 1.0f;
if (iter->next_pos > iter->end)
t_2 = iter->end;
else
t_2 = iter->next_pos;
if (iter->flipped)
{
iter->t_1 = t_2;
iter->t_2 = iter->pos;
}
else
{
iter->t_1 = iter->pos;
iter->t_2 = t_2;
}
}
static void
_cogl_texture_iter_begin (CoglTextureIter *iter,
gfloat t_1, gfloat t_2)
{
if (t_1 <= t_2)
{
iter->pos = t_1;
iter->end = t_2;
iter->flipped = FALSE;
}
else
{
iter->pos = t_2;
iter->end = t_1;
iter->flipped = TRUE;
}
_cogl_texture_iter_update (iter);
}
static void
_cogl_texture_iter_next (CoglTextureIter *iter)
{
iter->pos = iter->next_pos;
_cogl_texture_iter_update (iter);
}
static gboolean
_cogl_texture_iter_end (CoglTextureIter *iter)
{
return iter->pos >= iter->end;
}
/* This invokes the callback with enough quads to cover the manually
repeated range specified by the virtual texture coordinates without
emitting coordinates outside the range [0,1] */
void
_cogl_texture_iterate_manual_repeats (CoglTextureManualRepeatCallback callback,
float tx_1, float ty_1,
float tx_2, float ty_2,
void *user_data)
{
CoglTextureIter x_iter, y_iter;
for (_cogl_texture_iter_begin (&y_iter, ty_1, ty_2);
!_cogl_texture_iter_end (&y_iter);
_cogl_texture_iter_next (&y_iter))
for (_cogl_texture_iter_begin (&x_iter, tx_1, tx_2);
!_cogl_texture_iter_end (&x_iter);
_cogl_texture_iter_next (&x_iter))
{
float coords[4] = { x_iter.t_1, y_iter.t_1, x_iter.t_2, y_iter.t_2 };
callback (coords, user_data);
}
}
CoglHandle
cogl_texture_new_with_size (guint width,
guint height,
CoglTextureFlags flags,
CoglPixelFormat internal_format)
{
CoglHandle tex;
/* First try creating a fast-path non-sliced texture */
tex = _cogl_texture_2d_new_with_size (width, height, flags, internal_format);
/* If it fails resort to sliced textures */
if (tex == COGL_INVALID_HANDLE)
tex = _cogl_texture_2d_sliced_new_with_size (width,
height,
flags,
internal_format);
return tex;
}
CoglHandle
cogl_texture_new_from_data (guint width,
guint height,
CoglTextureFlags flags,
CoglPixelFormat format,
CoglPixelFormat internal_format,
guint rowstride,
const guchar *data)
{
CoglBitmap bitmap;
if (format == COGL_PIXEL_FORMAT_ANY)
return COGL_INVALID_HANDLE;
if (data == NULL)
return COGL_INVALID_HANDLE;
/* Rowstride from width if not given */
if (rowstride == 0)
rowstride = width * _cogl_get_format_bpp (format);
/* Wrap the data into a bitmap */
bitmap.width = width;
bitmap.height = height;
bitmap.data = (guchar *) data;
bitmap.format = format;
bitmap.rowstride = rowstride;
return cogl_texture_new_from_bitmap (&bitmap, flags, internal_format);
}
CoglHandle
cogl_texture_new_from_bitmap (CoglHandle bmp_handle,
CoglTextureFlags flags,
CoglPixelFormat internal_format)
{
CoglHandle tex;
/* First try putting the texture in the atlas */
if ((tex = _cogl_atlas_texture_new_from_bitmap (bmp_handle,
flags,
internal_format)))
return tex;
/* If that doesn't work try a fast path 2D texture */
if ((tex = _cogl_texture_2d_new_from_bitmap (bmp_handle,
flags,
internal_format)))
return tex;
/* Otherwise create a sliced texture */
return _cogl_texture_2d_sliced_new_from_bitmap (bmp_handle,
flags,
internal_format);
}
CoglHandle
cogl_texture_new_from_file (const gchar *filename,
CoglTextureFlags flags,
CoglPixelFormat internal_format,
GError **error)
{
CoglHandle bmp;
CoglHandle handle;
g_return_val_if_fail (error == NULL || *error == NULL, COGL_INVALID_HANDLE);
bmp = cogl_bitmap_new_from_file (filename, error);
if (bmp == COGL_INVALID_HANDLE)
return COGL_INVALID_HANDLE;
handle = cogl_texture_new_from_bitmap (bmp, flags, internal_format);
cogl_handle_unref (bmp);
return handle;
}
CoglHandle
cogl_texture_new_from_foreign (GLuint gl_handle,
GLenum gl_target,
GLuint width,
GLuint height,
GLuint x_pot_waste,
GLuint y_pot_waste,
CoglPixelFormat format)
{
return _cogl_texture_2d_sliced_new_from_foreign (gl_handle,
gl_target,
width,
height,
x_pot_waste,
y_pot_waste,
format);
}
CoglHandle
cogl_texture_new_from_sub_texture (CoglHandle full_texture,
gint sub_x,
gint sub_y,
gint sub_width,
gint sub_height)
{
return _cogl_sub_texture_new (full_texture, sub_x, sub_y,
sub_width, sub_height);
}
guint
cogl_texture_get_width (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return 0;
tex = COGL_TEXTURE (handle);
return tex->vtable->get_width (tex);
}
guint
cogl_texture_get_height (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return 0;
tex = COGL_TEXTURE (handle);
return tex->vtable->get_height (tex);
}
CoglPixelFormat
cogl_texture_get_format (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return COGL_PIXEL_FORMAT_ANY;
tex = COGL_TEXTURE (handle);
return tex->vtable->get_format (tex);
}
guint
cogl_texture_get_rowstride (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return 0;
/* FIXME: This function should go away. It previously just returned
the rowstride that was used to upload the data as far as I can
tell. This is not helpful */
tex = COGL_TEXTURE (handle);
/* Just guess at a suitable rowstride */
return (_cogl_get_format_bpp (cogl_texture_get_format (tex))
* cogl_texture_get_width (tex));
}
gint
cogl_texture_get_max_waste (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return 0;
tex = COGL_TEXTURE (handle);
return tex->vtable->get_max_waste (tex);
}
gboolean
cogl_texture_is_sliced (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return FALSE;
tex = COGL_TEXTURE (handle);
return tex->vtable->is_sliced (tex);
}
/* Some CoglTextures, notably sliced textures or atlas textures when repeating
* is used, will need to divide the coordinate space into multiple GL textures
* (or rather; in the case of atlases duplicate a single texture in multiple
* positions to handle repeating)
*
* This function helps you implement primitives using such textures by
* invoking a callback once for each sub texture that intersects a given
* region specified in texture coordinates.
*/
void
_cogl_texture_foreach_sub_texture_in_region (CoglHandle handle,
float virtual_tx_1,
float virtual_ty_1,
float virtual_tx_2,
float virtual_ty_2,
CoglTextureSliceCallback callback,
void *user_data)
{
CoglTexture *tex = COGL_TEXTURE (handle);
tex->vtable->foreach_sub_texture_in_region (tex,
virtual_tx_1,
virtual_ty_1,
virtual_tx_2,
virtual_ty_2,
callback,
user_data);
}
/* If this returns FALSE, that implies _foreach_sub_texture_in_region
* will be needed to iterate over multiple sub textures for regions whos
* texture coordinates extend out of the range [0,1]
*/
gboolean
_cogl_texture_can_hardware_repeat (CoglHandle handle)
{
CoglTexture *tex = (CoglTexture *)handle;
return tex->vtable->can_hardware_repeat (tex);
}
/* NB: You can't use this with textures comprised of multiple sub textures (use
* cogl_texture_is_sliced() to check) since coordinate transformation for such
* textures will be different for each slice. */
void
_cogl_texture_transform_coords_to_gl (CoglHandle handle,
float *s,
float *t)
{
CoglTexture *tex = COGL_TEXTURE (handle);
tex->vtable->transform_coords_to_gl (tex, s, t);
}
gboolean
_cogl_texture_transform_quad_coords_to_gl (CoglHandle handle,
float *coords)
{
CoglTexture *tex = COGL_TEXTURE (handle);
return tex->vtable->transform_quad_coords_to_gl (tex, coords);
}
GLenum
_cogl_texture_get_gl_format (CoglHandle handle)
{
CoglTexture *tex = COGL_TEXTURE (handle);
return tex->vtable->get_gl_format (tex);
}
gboolean
cogl_texture_get_gl_texture (CoglHandle handle,
GLuint *out_gl_handle,
GLenum *out_gl_target)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return FALSE;
tex = COGL_TEXTURE (handle);
return tex->vtable->get_gl_texture (tex, out_gl_handle, out_gl_target);
}
void
_cogl_texture_set_filters (CoglHandle handle,
GLenum min_filter,
GLenum mag_filter)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return;
tex = COGL_TEXTURE (handle);
tex->vtable->set_filters (tex, min_filter, mag_filter);
}
void
_cogl_texture_ensure_mipmaps (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return;
tex = COGL_TEXTURE (handle);
tex->vtable->ensure_mipmaps (tex);
}
void
_cogl_texture_ensure_non_quad_rendering (CoglHandle handle)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return;
tex = COGL_TEXTURE (handle);
return tex->vtable->ensure_non_quad_rendering (tex);
}
gboolean
cogl_texture_set_region (CoglHandle handle,
gint src_x,
gint src_y,
gint dst_x,
gint dst_y,
guint dst_width,
guint dst_height,
gint width,
gint height,
CoglPixelFormat format,
guint rowstride,
const guchar *data)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return FALSE;
tex = COGL_TEXTURE (handle);
return tex->vtable->set_region (tex,
src_x, src_y,
dst_x, dst_y,
dst_width, dst_height,
width, height,
format,
rowstride,
data);
}
/* Reads back the contents of a texture by rendering it to the framebuffer
* and reading back the resulting pixels.
*
* It will perform multiple renders if the texture is larger than the
* current glViewport.
*
* It assumes the projection and modelview have already been setup so
* that rendering to 0,0 with the same width and height of the viewport
* will exactly cover the viewport.
*
* NB: Normally this approach isn't normally used since we can just use
* glGetTexImage, but may be used as a fallback in some circumstances.
*/
static void
do_texture_draw_and_read (CoglHandle handle,
CoglBitmap *target_bmp,
GLint *viewport)
{
gint bpp;
float rx1, ry1;
float rx2, ry2;
float tx1, ty1;
float tx2, ty2;
int bw, bh;
CoglBitmap rect_bmp;
guint tex_width, tex_height;
bpp = _cogl_get_format_bpp (COGL_PIXEL_FORMAT_RGBA_8888);
tex_width = cogl_texture_get_width (handle);
tex_height = cogl_texture_get_height (handle);
ry1 = 0; ry2 = 0;
ty1 = 0; ty2 = 0;
/* Walk Y axis until whole bitmap height consumed */
for (bh = tex_height; bh > 0; bh -= viewport[3])
{
/* Rectangle Y coords */
ry1 = ry2;
ry2 += (bh < viewport[3]) ? bh : viewport[3];
/* Normalized texture Y coords */
ty1 = ty2;
ty2 = (ry2 / (float) tex_height);
rx1 = 0; rx2 = 0;
tx1 = 0; tx2 = 0;
/* Walk X axis until whole bitmap width consumed */
for (bw = tex_width; bw > 0; bw-=viewport[2])
{
/* Rectangle X coords */
rx1 = rx2;
rx2 += (bw < viewport[2]) ? bw : viewport[2];
/* Normalized texture X coords */
tx1 = tx2;
tx2 = (rx2 / (float) tex_width);
/* Draw a portion of texture */
cogl_rectangle_with_texture_coords (0, 0,
rx2 - rx1,
ry2 - ry1,
tx1, ty1,
tx2, ty2);
/* Read into a temporary bitmap */
rect_bmp.format = COGL_PIXEL_FORMAT_RGBA_8888;
rect_bmp.width = rx2 - rx1;
rect_bmp.height = ry2 - ry1;
rect_bmp.rowstride = bpp * rect_bmp.width;
rect_bmp.data = (guchar*) g_malloc (rect_bmp.rowstride *
rect_bmp.height);
_cogl_texture_driver_prep_gl_for_pixels_download (rect_bmp.rowstride,
bpp);
GE( glReadPixels (viewport[0], viewport[1],
rect_bmp.width,
rect_bmp.height,
GL_RGBA, GL_UNSIGNED_BYTE,
rect_bmp.data) );
/* Copy to target bitmap */
_cogl_bitmap_copy_subregion (&rect_bmp,
target_bmp,
0,0,
rx1,ry1,
rect_bmp.width,
rect_bmp.height);
/* Free temp bitmap */
g_free (rect_bmp.data);
}
}
}
/* Reads back the contents of a texture by rendering it to the framebuffer
* and reading back the resulting pixels.
*
* NB: Normally this approach isn't normally used since we can just use
* glGetTexImage, but may be used as a fallback in some circumstances.
*/
gboolean
_cogl_texture_draw_and_read (CoglHandle handle,
CoglBitmap *target_bmp,
GLuint target_gl_format,
GLuint target_gl_type)
{
gint bpp;
CoglHandle framebuffer;
int viewport[4];
CoglBitmap alpha_bmp;
CoglHandle prev_source;
CoglMatrixStack *projection_stack;
CoglMatrixStack *modelview_stack;
_COGL_GET_CONTEXT (ctx, FALSE);
bpp = _cogl_get_format_bpp (COGL_PIXEL_FORMAT_RGBA_8888);
framebuffer = _cogl_get_framebuffer ();
/* Viewport needs to have some size and be inside the window for this */
_cogl_framebuffer_get_viewport4fv (framebuffer, viewport);
if (viewport[0] < 0 || viewport[1] < 0 ||
viewport[2] <= 0 || viewport[3] <= 0)
return FALSE;
/* Setup orthographic projection into current viewport (0,0 in bottom-left
* corner to draw the texture upside-down so we match the way glReadPixels
* works)
*/
projection_stack = _cogl_framebuffer_get_projection_stack (framebuffer);
_cogl_matrix_stack_push (projection_stack);
_cogl_matrix_stack_load_identity (projection_stack);
_cogl_matrix_stack_ortho (projection_stack,
0, (float)(viewport[2]),
0, (float)(viewport[3]),
(float)(0),
(float)(100));
modelview_stack = _cogl_framebuffer_get_modelview_stack (framebuffer);
_cogl_matrix_stack_push (modelview_stack);
_cogl_matrix_stack_load_identity (modelview_stack);
/* Direct copy operation */
if (ctx->texture_download_material == COGL_INVALID_HANDLE)
{
ctx->texture_download_material = cogl_material_new ();
cogl_material_set_blend (ctx->texture_download_material,
"RGBA = ADD (SRC_COLOR, 0)",
NULL);
}
prev_source = cogl_handle_ref (ctx->source_material);
cogl_set_source (ctx->texture_download_material);
cogl_material_set_layer (ctx->texture_download_material, 0, handle);
cogl_material_set_layer_combine (ctx->texture_download_material,
0, /* layer */
"RGBA = REPLACE (TEXTURE)",
NULL);
do_texture_draw_and_read (handle, target_bmp, viewport);
/* Check whether texture has alpha and framebuffer not */
/* FIXME: For some reason even if ALPHA_BITS is 8, the framebuffer
still doesn't seem to have an alpha buffer. This might be just
a PowerVR issue.
GLint r_bits, g_bits, b_bits, a_bits;
GE( glGetIntegerv (GL_ALPHA_BITS, &a_bits) );
GE( glGetIntegerv (GL_RED_BITS, &r_bits) );
GE( glGetIntegerv (GL_GREEN_BITS, &g_bits) );
GE( glGetIntegerv (GL_BLUE_BITS, &b_bits) );
printf ("R bits: %d\n", r_bits);
printf ("G bits: %d\n", g_bits);
printf ("B bits: %d\n", b_bits);
printf ("A bits: %d\n", a_bits); */
if ((cogl_texture_get_format (handle) & COGL_A_BIT)/* && a_bits == 0*/)
{
guchar *srcdata;
guchar *dstdata;
guchar *srcpixel;
guchar *dstpixel;
gint x,y;
/* Create temp bitmap for alpha values */
alpha_bmp.format = COGL_PIXEL_FORMAT_RGBA_8888;
alpha_bmp.width = target_bmp->width;
alpha_bmp.height = target_bmp->height;
alpha_bmp.rowstride = bpp * alpha_bmp.width;
alpha_bmp.data = (guchar*) g_malloc (alpha_bmp.rowstride *
alpha_bmp.height);
/* Draw alpha values into RGB channels */
cogl_material_set_layer_combine (ctx->texture_download_material,
0, /* layer */
"RGBA = REPLACE (TEXTURE[A])",
NULL);
do_texture_draw_and_read (handle, &alpha_bmp, viewport);
/* Copy temp R to target A */
srcdata = alpha_bmp.data;
dstdata = target_bmp->data;
for (y=0; y<target_bmp->height; ++y)
{
for (x=0; x<target_bmp->width; ++x)
{
srcpixel = srcdata + x*bpp;
dstpixel = dstdata + x*bpp;
dstpixel[3] = srcpixel[0];
}
srcdata += alpha_bmp.rowstride;
dstdata += target_bmp->rowstride;
}
g_free (alpha_bmp.data);
}
/* Restore old state */
_cogl_matrix_stack_pop (modelview_stack);
_cogl_matrix_stack_pop (projection_stack);
/* restore the original material */
cogl_set_source (prev_source);
cogl_handle_unref (prev_source);
return TRUE;
}
gint
cogl_texture_get_data (CoglHandle handle,
CoglPixelFormat format,
guint rowstride,
guchar *data)
{
CoglTexture *tex;
if (!cogl_is_texture (handle))
return FALSE;
tex = COGL_TEXTURE (handle);
return tex->vtable->get_data (handle, format, rowstride, data);
}
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