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cogl-slip-stack: Store clip window rect entries in Cogl coordinates

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When glScissor is called it needs to pass coordinates in GL's
coordinate space where the origin is the bottom left. Previously this
conversion was done before storing the window rect in the clip
stack. However this might make it more difficult if we want to be able
to grab a handle to a clip stack and use it in different circumstances
later. This patch moves the coordinate conversion to inside the clip
state flushing code.
This commit is contained in:
Neil Roberts 2010-04-14 18:47:25 +01:00
parent 2f63146474
commit 07a76aacfb
1 changed files with 32 additions and 25 deletions
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53
cogl/cogl-clip-stack.c
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@ -128,7 +128,8 @@ struct _CoglClipStackEntryWindowRect
{
CoglClipStackEntry _parent_data;
/* The window space rectangle for this clip */
/* The window space rectangle for this clip. This is stored in
Cogl's coordinate space (ie, 0,0 is the top left) */
int x0;
int y0;
int x1;
@ -409,7 +410,6 @@ cogl_clip_push_window_rectangle (int x_offset,
CoglHandle framebuffer;
CoglClipStackState *clip_state;
CoglClipStack *stack;
int framebuffer_height;
CoglClipStackEntryWindowRect *entry;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
@ -423,31 +423,14 @@ cogl_clip_push_window_rectangle (int x_offset,
stack = clip_state->stacks->data;
framebuffer_height = _cogl_framebuffer_get_height (framebuffer);
entry = _cogl_clip_stack_push_entry (stack,
sizeof (CoglClipStackEntryWindowRect),
COGL_CLIP_STACK_WINDOW_RECT);
/* We store the entry coordinates in OpenGL window coordinate space and so
* because Cogl defines the window origin to be top left but OpenGL defines
* it as bottom left we may need to convert the incoming coordinates.
*
* NB: Cogl forces all offscreen rendering to be done upside down so in this
* case no conversion is needed.
*/
entry->x0 = x_offset;
entry->x1 = x_offset + width;
if (cogl_is_offscreen (framebuffer))
{
entry->y0 = y_offset;
entry->y1 = y_offset + height;
}
else
{
entry->y0 = framebuffer_height - y_offset - height;
entry->y1 = framebuffer_height - y_offset;
}
clip_state->stack_dirty = TRUE;
}
@ -835,14 +818,38 @@ _cogl_flush_clip_state (CoglClipStackState *clip_state)
if (using_clip_planes)
enable_clip_planes ();
if (scissor_x0 >= scissor_x1 || scissor_y0 >= scissor_y1)
scissor_x0 = scissor_y0 = scissor_x1 = scissor_y1 = 0;
if (!(scissor_x0 == 0 && scissor_y0 == 0 &&
scissor_x1 == G_MAXINT && scissor_y1 == G_MAXINT))
{
int scissor_y_start;
if (scissor_x0 >= scissor_x1 || scissor_y0 >= scissor_y1)
scissor_x0 = scissor_y0 = scissor_x1 = scissor_y1 = scissor_y_start = 0;
else
{
CoglHandle framebuffer = _cogl_get_framebuffer ();
/* We store the entry coordinates in Cogl coordinate space
* but OpenGL requires the window origin to be the bottom
* left so we may need to convert the incoming coordinates.
*
* NB: Cogl forces all offscreen rendering to be done upside
* down so in this case no conversion is needed.
*/
if (cogl_is_offscreen (framebuffer))
scissor_y_start = scissor_y0;
else
{
int framebuffer_height =
_cogl_framebuffer_get_height (framebuffer);
scissor_y_start = framebuffer_height - scissor_y1;
}
}
GE (glEnable (GL_SCISSOR_TEST));
GE (glScissor (scissor_x0, scissor_y0,
GE (glScissor (scissor_x0, scissor_y_start,
scissor_x1 - scissor_x0,
scissor_y1 - scissor_y0));
}