void
add_stencil_clip_rectangle (float x_1,
float y_1,
float x_2,
float y_2,
gboolean first)
{
CoglHandle current_source;
CoglHandle framebuffer = _cogl_get_framebuffer ();
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* We don't log changes to the stencil buffer so need to flush any
* batched geometry before we start... */
_cogl_journal_flush ();
_cogl_framebuffer_flush_state (framebuffer, 0);
/* temporarily swap in our special stenciling material */
current_source = cogl_handle_ref (ctx->source_material);
cogl_set_source (ctx->stencil_material);
if (first)
{
GE( glEnable (GL_STENCIL_TEST) );
/* Initially disallow everything */
GE( glClearStencil (0) );
GE( glClear (GL_STENCIL_BUFFER_BIT) );
/* Punch out a hole to allow the rectangle */
GE( glStencilFunc (GL_NEVER, 0x1, 0x1) );
GE( glStencilOp (GL_REPLACE, GL_REPLACE, GL_REPLACE) );
cogl_rectangle (x_1, y_1, x_2, y_2);
}
else
{
CoglMatrixStack *modelview_stack =
_cogl_framebuffer_get_modelview_stack (framebuffer);
CoglMatrixStack *projection_stack =
_cogl_framebuffer_get_projection_stack (framebuffer);
/* Add one to every pixel of the stencil buffer in the
rectangle */
GE( glStencilFunc (GL_NEVER, 0x1, 0x3) );
GE( glStencilOp (GL_INCR, GL_INCR, GL_INCR) );
cogl_rectangle (x_1, y_1, x_2, y_2);
/* make sure our rectangle hits the stencil buffer before we
* change the stencil operation */
_cogl_journal_flush ();
/* Subtract one from all pixels in the stencil buffer so that
only pixels where both the original stencil buffer and the
rectangle are set will be valid */
GE( glStencilOp (GL_DECR, GL_DECR, GL_DECR) );
_cogl_matrix_stack_push (projection_stack);
_cogl_matrix_stack_load_identity (projection_stack);
_cogl_matrix_stack_push (modelview_stack);
_cogl_matrix_stack_load_identity (modelview_stack);
cogl_rectangle (-1.0, -1.0, 1.0, 1.0);
_cogl_matrix_stack_pop (modelview_stack);
_cogl_matrix_stack_pop (projection_stack);
}
/* make sure our rectangles hit the stencil buffer before we restore
* the stencil function / operation */
_cogl_journal_flush ();
/* Restore the stencil mode */
GE( glStencilFunc (GL_EQUAL, 0x1, 0x1) );
GE( glStencilOp (GL_KEEP, GL_KEEP, GL_KEEP) );
/* restore the original source material */
cogl_set_source (current_source);
cogl_handle_unref (current_source);
}
/* 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)
{
int bpp;
CoglFramebuffer *framebuffer;
int viewport[4];
CoglBitmap *alpha_bmp;
CoglMatrixStack *projection_stack;
CoglMatrixStack *modelview_stack;
int target_width = _cogl_bitmap_get_width (target_bmp);
int target_height = _cogl_bitmap_get_height (target_bmp);
int target_rowstride = _cogl_bitmap_get_rowstride (target_bmp);
_COGL_GET_CONTEXT (ctx, FALSE);
bpp = _cogl_get_format_bpp (COGL_PIXEL_FORMAT_RGBA_8888);
framebuffer = _cogl_get_draw_buffer ();
/* 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 top-left
* corner to draw the texture upside-down so we match the way cogl_read_pixels
* 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]),
(float)(viewport[3]), 0,
(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_pipeline == COGL_INVALID_HANDLE)
{
ctx->texture_download_pipeline = cogl_pipeline_new ();
cogl_pipeline_set_blend (ctx->texture_download_pipeline,
"RGBA = ADD (SRC_COLOR, 0)",
NULL);
}
cogl_push_source (ctx->texture_download_pipeline);
cogl_pipeline_set_layer_texture (ctx->texture_download_pipeline, 0, handle);
cogl_pipeline_set_layer_combine (ctx->texture_download_pipeline,
0, /* layer */
"RGBA = REPLACE (TEXTURE)",
NULL);
cogl_pipeline_set_layer_filters (ctx->texture_download_pipeline, 0,
COGL_PIPELINE_FILTER_NEAREST,
COGL_PIPELINE_FILTER_NEAREST);
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*/)
{
guint8 *srcdata;
guint8 *dstdata;
guint8 *srcpixel;
guint8 *dstpixel;
int x,y;
int alpha_rowstride = bpp * target_width;
if ((dstdata = _cogl_bitmap_map (target_bmp,
COGL_BUFFER_ACCESS_WRITE,
COGL_BUFFER_MAP_HINT_DISCARD)) == NULL)
return FALSE;
srcdata = g_malloc (alpha_rowstride * target_height);
/* Create temp bitmap for alpha values */
alpha_bmp = _cogl_bitmap_new_from_data (srcdata,
COGL_PIXEL_FORMAT_RGBA_8888,
target_width, target_height,
alpha_rowstride,
(CoglBitmapDestroyNotify) g_free,
NULL);
/* Draw alpha values into RGB channels */
cogl_pipeline_set_layer_combine (ctx->texture_download_pipeline,
0, /* layer */
"RGBA = REPLACE (TEXTURE[A])",
NULL);
do_texture_draw_and_read (handle, alpha_bmp, viewport);
/* Copy temp R to target A */
for (y=0; y<target_height; ++y)
{
for (x=0; x<target_width; ++x)
{
srcpixel = srcdata + x*bpp;
dstpixel = dstdata + x*bpp;
dstpixel[3] = srcpixel[0];
}
srcdata += alpha_rowstride;
dstdata += target_rowstride;
}
_cogl_bitmap_unmap (target_bmp);
cogl_object_unref (alpha_bmp);
}
/* Restore old state */
_cogl_matrix_stack_pop (modelview_stack);
_cogl_matrix_stack_pop (projection_stack);
/* restore the original pipeline */
cogl_pop_source ();
return TRUE;
}
