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* clutter/cogl/gles/cogl-texture.c:

Browse Source 
(cogl_texture_download_from_gl:) Implemented a workaround
	for missing alpha framebuffer channel. There are still
	some issues with detecting whether alpha is present in the
	framebuffer. See comments in code. Test-cogl-tex-getset now
	successfully retrieves a RGBA texture image data.
This commit is contained in:
Ivan Leben 2008-05-20 10:37:36 +00:00
parent 3d9f83019d
commit 2008a03a6b
2 changed files with 181 additions and 104 deletions
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9
ChangeLog
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@ -1,3 +1,12 @@
2008-05-20 Ivan Leben <ivan@o-hand.com>
* clutter/cogl/gles/cogl-texture.c:
(cogl_texture_download_from_gl:) Implemented a workaround
for missing alpha framebuffer channel. There are still
some issues with detecting whether alpha is present in the
framebuffer. See comments in code. Test-cogl-tex-getset now
successfully retrieves a RGBA texture image data.
2008-05-19 Ivan Leben <ivan@o-hand.com>
* clutter/cogl/gles/cogl-texture.c:

276
clutter/cogl/gles/cogl-texture.c
View File

@ -238,6 +238,125 @@ _cogl_texture_upload_to_gl (CoglTexture *tex)
return TRUE;
}
static void
_cogl_texture_draw_and_read (CoglTexture *tex,
CoglBitmap *target_bmp,
ClutterColor *back_color,
GLint *viewport)
{
gint bpp;
ClutterFixed rx1, ry1;
ClutterFixed rx2, ry2;
ClutterFixed tx1, ty1;
ClutterFixed tx2, ty2;
int bw, bh;
CoglBitmap rect_bmp;
CoglHandle handle;
handle = _cogl_texture_handle_from_pointer (tex);
bpp = _cogl_get_format_bpp (COGL_PIXEL_FORMAT_RGBA_8888);
/* If whole image fits into the viewport and target buffer
has got no special rowstride, we can do it in one pass */
if (tex->bitmap.width < viewport[2] - viewport[0] &&
tex->bitmap.height < viewport[3] - viewport[1] &&
tex->bitmap.rowstride == bpp * tex->bitmap.width)
{
/* Clear buffer with transparent black, draw with white
for direct copy to framebuffer */
cogl_paint_init (back_color);
/* Draw the texture image */
cogl_texture_rectangle (handle,
0, 0,
CLUTTER_INT_TO_FIXED (tex->bitmap.width),
CLUTTER_INT_TO_FIXED (tex->bitmap.height),
0, 0, CFX_ONE, CFX_ONE);
/* Read into target bitmap */
GE( glPixelStorei (GL_PACK_ALIGNMENT, 1) );
GE( glReadPixels (viewport[0], viewport[1],
tex->bitmap.width,
tex->bitmap.height,
GL_RGBA, GL_UNSIGNED_BYTE,
target_bmp->data) );
}
else
{
ry1 = 0; ry2 = 0;
ty1 = 0; ty2 = 0;
#define CFIX CLUTTER_INT_TO_FIXED
/* Walk Y axis until whole bitmap height consumed */
for (bh = tex->bitmap.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 = CFX_QDIV (CFIX (ry2), CFIX (tex->bitmap.height));
rx1 = 0; rx2 = 0;
tx1 = 0; tx2 = 0;
/* Walk X axis until whole bitmap width consumed */
for (bw = tex->bitmap.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 = CFX_QDIV (CFIX (rx2), CFIX (tex->bitmap.width));
/* Clear buffer with transparent black, draw with white
for direct copy to framebuffer */
cogl_paint_init (back_color);
/* Draw a portion of texture */
cogl_texture_rectangle (handle,
0, 0,
CFIX (rx2 - rx1),
CFIX (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);
GE( glPixelStorei (GL_PACK_ALIGNMENT, 1) );
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);
}
}
#undef CFIX
}
}
static gboolean
_cogl_texture_download_from_gl (CoglTexture *tex,
CoglBitmap *target_bmp,
@ -246,21 +365,13 @@ _cogl_texture_download_from_gl (CoglTexture *tex,
{
gint bpp;
GLint viewport[4];
CoglHandle handle;
ClutterColor cback = {0x0, 0x0, 0x0, 0x0};
ClutterColor cwhite = {0xFF, 0xFF, 0xFF, 0xFF};
CoglBitmap rect_bmp;
ClutterFixed rx1, ry1;
ClutterFixed rx2, ry2;
ClutterFixed tx1, ty1;
ClutterFixed tx2, ty2;
int bw, bh;
CoglBitmap alpha_bmp;
COGLenum old_src_factor;
COGLenum old_dst_factor;
_COGL_GET_CONTEXT (ctx, FALSE);
handle = _cogl_texture_handle_from_pointer (tex);
bpp = _cogl_get_format_bpp (COGL_PIXEL_FORMAT_RGBA_8888);
/* Viewport needs to have some size and be inside the window for this */
@ -290,113 +401,70 @@ _cogl_texture_download_from_gl (CoglTexture *tex,
/* Draw to all channels */
cogl_draw_buffer (COGL_WINDOW_BUFFER | COGL_MASK_BUFFER, 0);
/* Store old blending factors and setup direct copy operation */
/* Store old blending factors */
old_src_factor = ctx->blend_src_factor;
old_dst_factor = ctx->blend_dst_factor;
/* Direct copy operation */
cogl_color (&cwhite);
cogl_blend_func (CGL_ONE, CGL_ZERO);
_cogl_texture_draw_and_read (tex, target_bmp,
&cwhite, viewport);
/* If whole image fits into the viewport and target buffer
has got no special rowstride, we can do it in one pass */
if (tex->bitmap.width < viewport[2] - viewport[0] &&
tex->bitmap.height < viewport[3] - viewport[1] &&
tex->bitmap.rowstride == bpp * tex->bitmap.width)
/* 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 ((tex->bitmap.format & COGL_A_BIT) && a_bits == 0) */
{
/* Clear buffer with transparent black, draw with white
for direct copy to framebuffer */
cogl_paint_init (&cback);
cogl_color (&cwhite);
guchar *srcdata;
guchar *dstdata;
guchar *srcpixel;
guchar *dstpixel;
gint x,y;
/* Draw the texture image */
cogl_texture_rectangle (handle,
0, 0,
CLUTTER_INT_TO_FIXED (tex->bitmap.width),
CLUTTER_INT_TO_FIXED (tex->bitmap.height),
0, 0, CFX_ONE, CFX_ONE);
/* 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);
/* Read into target bitmap */
GE( glPixelStorei (GL_PACK_ALIGNMENT, 1) );
GE( glReadPixels (viewport[0], viewport[1],
tex->bitmap.width,
tex->bitmap.height,
GL_RGBA, GL_UNSIGNED_BYTE,
target_bmp->data) );
}
else
{
ry1 = 0; ry2 = 0;
ty1 = 0; ty2 = 0;
/* Draw alpha values into RGB channels */
cogl_blend_func (CGL_ZERO, CGL_SRC_ALPHA);
_cogl_texture_draw_and_read (tex, &alpha_bmp,
&cwhite, viewport);
#define CFIX CLUTTER_INT_TO_FIXED
/* Copy temp R to target A */
srcdata = alpha_bmp.data;
dstdata = target_bmp->data;
/* Walk Y axis until whole bitmap height consumed */
for (bh = tex->bitmap.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 = CFX_QDIV (CFIX (ry2), CFIX (tex->bitmap.height));
rx1 = 0; rx2 = 0;
tx1 = 0; tx2 = 0;
/* Walk X axis until whole bitmap width consumed */
for (bw = tex->bitmap.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 = CFX_QDIV (CFIX (rx2), CFIX (tex->bitmap.width));
/* Clear buffer with transparent black, draw with white
for direct copy to framebuffer */
cogl_paint_init (&cback);
cogl_color (&cwhite);
/* Draw a portion of texture */
cogl_texture_rectangle (handle,
0, 0,
CFIX (rx2 - rx1),
CFIX (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);
GE( glPixelStorei (GL_PACK_ALIGNMENT, 1) );
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);
}
}
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;
}
#undef CFIX
g_free (alpha_bmp.data);
}
/* Restore old state */
glMatrixMode (GL_PROJECTION);
glPopMatrix ();
glMatrixMode (GL_MODELVIEW);