mutter/cogl/cogl-clip-state.c

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009,2010 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, see <http://www.gnu.org/licenses/>.
*
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <math.h>
#include <glib.h>
#include "cogl.h"
#include "cogl-clip-stack.h"
#include "cogl-clip-state.h"
#include "cogl-context.h"
#include "cogl-internal.h"
#include "cogl-framebuffer-private.h"
#include "cogl-journal-private.h"
#include "cogl-util.h"
void
cogl_clip_push_window_rectangle (int x_offset,
int y_offset,
int width,
int height)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
CoglHandle stack;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* We don't log clip stack changes in the journal so we must flush
* it before making modifications */
_cogl_journal_flush ();
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
stack = clip_state->stacks->data;
_cogl_clip_stack_push_window_rectangle (stack, x_offset, y_offset,
width, height);
clip_state->stack_dirty = TRUE;
}
/* XXX: This is deprecated API */
void
cogl_clip_push_window_rect (float x_offset,
float y_offset,
float width,
float height)
{
cogl_clip_push_window_rectangle (x_offset, y_offset, width, height);
}
/* Scale from OpenGL normalized device coordinates (ranging from -1 to 1)
* to Cogl window/framebuffer coordinates (ranging from 0 to buffer-size) with
* (0,0) being top left. */
#define VIEWPORT_TRANSFORM_X(x, vp_origin_x, vp_width) \
( ( ((x) + 1.0) * ((vp_width) / 2.0) ) + (vp_origin_x) )
/* Note: for Y we first flip all coordinates around the X axis while in
* normalized device coodinates */
#define VIEWPORT_TRANSFORM_Y(y, vp_origin_y, vp_height) \
( ( ((-(y)) + 1.0) * ((vp_height) / 2.0) ) + (vp_origin_y) )
/* Transform a homogeneous vertex position from model space to Cogl
* window coordinates (with 0,0 being top left) */
static void
transform_point (CoglMatrix *matrix_mv,
CoglMatrix *matrix_p,
float *viewport,
float *x,
float *y)
{
float z = 0;
float w = 1;
/* Apply the modelview matrix transform */
cogl_matrix_transform_point (matrix_mv, x, y, &z, &w);
/* Apply the projection matrix transform */
cogl_matrix_transform_point (matrix_p, x, y, &z, &w);
/* Perform perspective division */
*x /= w;
*y /= w;
/* Apply viewport transform */
*x = VIEWPORT_TRANSFORM_X (*x, viewport[0], viewport[2]);
*y = VIEWPORT_TRANSFORM_Y (*y, viewport[1], viewport[3]);
}
#undef VIEWPORT_SCALE_X
#undef VIEWPORT_SCALE_Y
/* Try to push a rectangle given in object coordinates as a rectangle in window
* coordinates instead of object coordinates */
gboolean
try_pushing_rect_as_window_rect (float x_1,
float y_1,
float x_2,
float y_2)
{
CoglMatrix matrix;
CoglMatrix matrix_p;
float v[4];
cogl_get_modelview_matrix (&matrix);
/* If the modelview meets these constraints then a transformed rectangle
* should still be a rectangle when it reaches screen coordinates.
*
* FIXME: we are are making certain assumptions about the projection
* matrix a.t.m and should really be looking at the combined modelview
* and projection matrix.
* FIXME: we don't consider rotations that are a multiple of 90 degrees
* which could be quite common.
*/
if (matrix.xy != 0 || matrix.xz != 0 ||
matrix.yx != 0 || matrix.yz != 0 ||
matrix.zx != 0 || matrix.zy != 0)
return FALSE;
cogl_get_projection_matrix (&matrix_p);
cogl_get_viewport (v);
transform_point (&matrix, &matrix_p, v, &x_1, &y_1);
transform_point (&matrix, &matrix_p, v, &x_2, &y_2);
/* Consider that the modelview matrix may flip the rectangle
* along the x or y axis... */
#define SWAP(A,B) do { float tmp = B; B = A; A = tmp; } while (0)
if (x_1 > x_2)
SWAP (x_1, x_2);
if (y_1 > y_2)
SWAP (y_1, y_2);
#undef SWAP
cogl_clip_push_window_rectangle (COGL_UTIL_NEARBYINT (x_1),
COGL_UTIL_NEARBYINT (y_1),
COGL_UTIL_NEARBYINT (x_2 - x_1),
COGL_UTIL_NEARBYINT (y_2 - y_1));
return TRUE;
}
void
cogl_clip_push_rectangle (float x_1,
float y_1,
float x_2,
float y_2)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
CoglHandle stack;
CoglMatrix modelview_matrix;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* We don't log clip stack changes in the journal so we must flush
* it before making modifications */
_cogl_journal_flush ();
/* Try and catch window space rectangles so we can redirect to
* cogl_clip_push_window_rect which will use scissoring. */
if (try_pushing_rect_as_window_rect (x_1, y_1, x_2, y_2))
return;
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
stack = clip_state->stacks->data;
cogl_get_modelview_matrix (&modelview_matrix);
_cogl_clip_stack_push_rectangle (stack, x_1, y_1, x_2, y_2,
&modelview_matrix);
clip_state->stack_dirty = TRUE;
}
/* XXX: Deprecated API */
void
cogl_clip_push (float x_offset,
float y_offset,
float width,
float height)
{
cogl_clip_push_rectangle (x_offset,
y_offset,
x_offset + width,
y_offset + height);
}
void
cogl_clip_push_from_path_preserve (void)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
CoglHandle stack;
CoglMatrix modelview_matrix;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* We don't log clip stack changes in the journal so we must flush
* it before making modifications */
_cogl_journal_flush ();
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
stack = clip_state->stacks->data;
cogl_get_modelview_matrix (&modelview_matrix);
_cogl_clip_stack_push_from_path (stack, cogl_path_get (),
&modelview_matrix);
clip_state->stack_dirty = TRUE;
}
void
cogl_clip_push_from_path (void)
{
cogl_clip_push_from_path_preserve ();
cogl_path_new ();
}
static void
_cogl_clip_pop_real (CoglClipState *clip_state)
{
CoglHandle stack;
/* We don't log clip stack changes in the journal so we must flush
* it before making modifications */
_cogl_journal_flush ();
stack = clip_state->stacks->data;
_cogl_clip_stack_pop (stack);
clip_state->stack_dirty = TRUE;
}
void
cogl_clip_pop (void)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
_cogl_clip_pop_real (clip_state);
}
void
_cogl_clip_state_flush (CoglClipState *clip_state)
{
CoglHandle stack;
if (!clip_state->stack_dirty)
return;
/* The current primitive journal does not support tracking changes to the
* clip stack... */
_cogl_journal_flush ();
/* XXX: the handling of clipping is quite complex. It may involve use of
* the Cogl Journal or other Cogl APIs which may end up recursively
* wanting to ensure the clip state is flushed. We need to ensure we
* don't recurse infinitely...
*/
clip_state->stack_dirty = FALSE;
stack = clip_state->stacks->data;
_cogl_clip_stack_flush (stack, &clip_state->stencil_used);
}
/* XXX: This should never have been made public API! */
void
cogl_clip_ensure (void)
{
CoglClipState *clip_state;
clip_state = _cogl_framebuffer_get_clip_state (_cogl_get_framebuffer ());
_cogl_clip_state_flush (clip_state);
}
static void
_cogl_clip_stack_save_real (CoglClipState *clip_state)
{
CoglHandle stack;
/* We don't log clip stack changes in the journal so we must flush
* it before making modifications */
_cogl_journal_flush ();
stack = _cogl_clip_stack_new ();
clip_state->stacks = g_slist_prepend (clip_state->stacks, stack);
clip_state->stack_dirty = TRUE;
}
void
cogl_clip_stack_save (void)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
_cogl_clip_stack_save_real (clip_state);
}
static void
_cogl_clip_stack_restore_real (CoglClipState *clip_state)
{
CoglHandle stack;
g_return_if_fail (clip_state->stacks != NULL);
/* We don't log clip stack changes in the journal so we must flush
* it before making modifications */
_cogl_journal_flush ();
stack = clip_state->stacks->data;
cogl_handle_unref (stack);
/* Revert to an old stack */
clip_state->stacks = g_slist_delete_link (clip_state->stacks,
clip_state->stacks);
clip_state->stack_dirty = TRUE;
}
void
cogl_clip_stack_restore (void)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
_cogl_clip_stack_restore_real (clip_state);
}
void
_cogl_clip_state_init (CoglClipState *clip_state)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
clip_state->stacks = NULL;
clip_state->stack_dirty = TRUE;
/* Add an intial stack */
_cogl_clip_stack_save_real (clip_state);
}
void
_cogl_clip_state_destroy (CoglClipState *clip_state)
{
/* Destroy all of the stacks */
while (clip_state->stacks)
_cogl_clip_stack_restore_real (clip_state);
}
void
_cogl_clip_state_dirty (CoglClipState *clip_state)
{
clip_state->stack_dirty = TRUE;
}
CoglHandle
_cogl_get_clip_stack (void)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
_COGL_GET_CONTEXT (ctx, COGL_INVALID_HANDLE);
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
return clip_state->stacks->data;
}
void
_cogl_set_clip_stack (CoglHandle handle)
{
CoglHandle framebuffer;
CoglClipState *clip_state;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
if (handle == COGL_INVALID_HANDLE)
return;
framebuffer = _cogl_get_framebuffer ();
clip_state = _cogl_framebuffer_get_clip_state (framebuffer);
/* Replace the top of the stack of stacks */
cogl_handle_ref (handle);
cogl_handle_unref (clip_state->stacks->data);
clip_state->stacks->data = handle;
}