* 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.
This commit is contained in:
Ivan Leben 2008-05-20 10:37:36 +00:00
parent 006573ac61
commit 4cb0d58ceb

View File

@ -238,63 +238,24 @@ _cogl_texture_upload_to_gl (CoglTexture *tex)
return TRUE;
}
static gboolean
_cogl_texture_download_from_gl (CoglTexture *tex,
static void
_cogl_texture_draw_and_read (CoglTexture *tex,
CoglBitmap *target_bmp,
GLuint target_gl_format,
GLuint target_gl_type)
ClutterColor *back_color,
GLint *viewport)
{
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;
COGLenum old_src_factor;
COGLenum old_dst_factor;
_COGL_GET_CONTEXT (ctx, FALSE);
CoglBitmap rect_bmp;
CoglHandle handle;
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 */
GE( glGetIntegerv (GL_VIEWPORT, 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) */
GE( glMatrixMode (GL_PROJECTION) );
GE( glPushMatrix () );
GE( glLoadIdentity () );
GE( glOrthox (0, CLUTTER_INT_TO_FIXED (viewport[2]),
0, CLUTTER_INT_TO_FIXED (viewport[3]),
CLUTTER_INT_TO_FIXED (0),
CLUTTER_INT_TO_FIXED (100)) );
GE( glMatrixMode (GL_MODELVIEW) );
GE( glPushMatrix () );
GE( glLoadIdentity () );
/* Draw to all channels */
cogl_draw_buffer (COGL_WINDOW_BUFFER | COGL_MASK_BUFFER, 0);
/* Store old blending factors and setup direct copy operation */
old_src_factor = ctx->blend_src_factor;
old_dst_factor = ctx->blend_dst_factor;
cogl_blend_func (CGL_ONE, CGL_ZERO);
/* 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] &&
@ -303,8 +264,7 @@ _cogl_texture_download_from_gl (CoglTexture *tex,
{
/* Clear buffer with transparent black, draw with white
for direct copy to framebuffer */
cogl_paint_init (&cback);
cogl_color (&cwhite);
cogl_paint_init (back_color);
/* Draw the texture image */
cogl_texture_rectangle (handle,
@ -355,8 +315,7 @@ _cogl_texture_download_from_gl (CoglTexture *tex,
/* Clear buffer with transparent black, draw with white
for direct copy to framebuffer */
cogl_paint_init (&cback);
cogl_color (&cwhite);
cogl_paint_init (back_color);
/* Draw a portion of texture */
cogl_texture_rectangle (handle,
@ -396,7 +355,116 @@ _cogl_texture_download_from_gl (CoglTexture *tex,
#undef CFIX
}
}
static gboolean
_cogl_texture_download_from_gl (CoglTexture *tex,
CoglBitmap *target_bmp,
GLuint target_gl_format,
GLuint target_gl_type)
{
gint bpp;
GLint viewport[4];
ClutterColor cwhite = {0xFF, 0xFF, 0xFF, 0xFF};
CoglBitmap alpha_bmp;
COGLenum old_src_factor;
COGLenum old_dst_factor;
_COGL_GET_CONTEXT (ctx, FALSE);
bpp = _cogl_get_format_bpp (COGL_PIXEL_FORMAT_RGBA_8888);
/* Viewport needs to have some size and be inside the window for this */
GE( glGetIntegerv (GL_VIEWPORT, 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) */
GE( glMatrixMode (GL_PROJECTION) );
GE( glPushMatrix () );
GE( glLoadIdentity () );
GE( glOrthox (0, CLUTTER_INT_TO_FIXED (viewport[2]),
0, CLUTTER_INT_TO_FIXED (viewport[3]),
CLUTTER_INT_TO_FIXED (0),
CLUTTER_INT_TO_FIXED (100)) );
GE( glMatrixMode (GL_MODELVIEW) );
GE( glPushMatrix () );
GE( glLoadIdentity () );
/* Draw to all channels */
cogl_draw_buffer (COGL_WINDOW_BUFFER | COGL_MASK_BUFFER, 0);
/* 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);
/* 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) */
{
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_blend_func (CGL_ZERO, CGL_SRC_ALPHA);
_cogl_texture_draw_and_read (tex, &alpha_bmp,
&cwhite, 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 */
glMatrixMode (GL_PROJECTION);
glPopMatrix ();
glMatrixMode (GL_MODELVIEW);