static void *
_cogl_matrix_stack_push_replacement_entry (CoglMatrixStack *stack,
CoglMatrixOp operation)
{
CoglMatrixEntry *old_top = stack->last_entry;
CoglMatrixEntry *new_top;
/* This would only be called for operations that completely replace
* the matrix. In that case we don't need to keep a reference to
* anything up to the last save entry. This optimisation could be
* important for applications that aren't using the stack but
* instead just perform their own matrix manipulations and load a
* new stack every frame. If this optimisation isn't done then the
* stack would just grow endlessly. See the comments
* cogl_matrix_stack_pop for a description of how popping works. */
for (new_top = old_top;
new_top->op != COGL_MATRIX_OP_SAVE && new_top->parent;
new_top = new_top->parent)
;
cogl_matrix_entry_ref (new_top);
cogl_matrix_entry_unref (old_top);
stack->last_entry = new_top;
return _cogl_matrix_stack_push_operation (stack, operation);
}
void
_cogl_context_set_current_modelview_entry (CoglContext *context,
CoglMatrixEntry *entry)
{
cogl_matrix_entry_ref (entry);
if (context->current_modelview_entry)
cogl_matrix_entry_unref (context->current_modelview_entry);
context->current_modelview_entry = entry;
}
CoglClipStack *
_cogl_clip_stack_push_primitive (CoglClipStack *stack,
CoglPrimitive *primitive,
float bounds_x1,
float bounds_y1,
float bounds_x2,
float bounds_y2,
CoglMatrixEntry *modelview_entry,
CoglMatrixEntry *projection_entry,
const float *viewport)
{
CoglClipStackPrimitive *entry;
CoglMatrix modelview;
CoglMatrix projection;
float transformed_corners[8];
entry = _cogl_clip_stack_push_entry (stack,
sizeof (CoglClipStackPrimitive),
COGL_CLIP_STACK_PRIMITIVE);
entry->primitive = cogl_object_ref (primitive);
entry->matrix_entry = cogl_matrix_entry_ref (modelview_entry);
entry->bounds_x1 = bounds_x1;
entry->bounds_y1 = bounds_y1;
entry->bounds_x2 = bounds_x2;
entry->bounds_y2 = bounds_y2;
cogl_matrix_entry_get (modelview_entry, &modelview);
cogl_matrix_entry_get (projection_entry, &projection);
get_transformed_corners (bounds_x1, bounds_y1, bounds_x2, bounds_y2,
&modelview,
&projection,
viewport,
transformed_corners);
/* NB: this is referring to the bounds in window coordinates as opposed
* to the bounds above in primitive local coordinates. */
_cogl_clip_stack_entry_set_bounds ((CoglClipStack *) entry,
transformed_corners);
return (CoglClipStack *) entry;
}
CoglMatrixStack *
cogl_matrix_stack_new (CoglContext *ctx)
{
CoglMatrixStack *stack = g_slice_new (CoglMatrixStack);
if (G_UNLIKELY (cogl_matrix_stack_magazine == NULL))
{
cogl_matrix_stack_magazine =
_cogl_magazine_new (sizeof (CoglMatrixEntryFull), 20);
cogl_matrix_stack_matrices_magazine =
_cogl_magazine_new (sizeof (CoglMatrix), 20);
}
stack->context = ctx;
stack->last_entry = NULL;
cogl_matrix_entry_ref (&ctx->identity_entry);
_cogl_matrix_stack_push_entry (stack, &ctx->identity_entry);
return _cogl_matrix_stack_object_new (stack);
}
/* NB: This function can report false negatives since it never does a
* deep comparison of the stack matrices. */
CoglBool
_cogl_matrix_entry_cache_maybe_update (CoglMatrixEntryCache *cache,
CoglMatrixEntry *entry,
CoglBool flip)
{
CoglBool is_identity;
CoglBool updated = FALSE;
if (cache->flipped != flip)
{
cache->flipped = flip;
updated = TRUE;
}
is_identity = (entry->op == COGL_MATRIX_OP_LOAD_IDENTITY);
if (cache->flushed_identity != is_identity)
{
cache->flushed_identity = is_identity;
updated = TRUE;
}
if (cache->entry != entry)
{
cogl_matrix_entry_ref (entry);
if (cache->entry)
cogl_matrix_entry_unref (cache->entry);
cache->entry = entry;
/* We want to make sure here that if the cache->entry and the
* given @entry are both identity matrices then even though they
* are different entries we don't want to consider this an
* update...
*/
updated |= !is_identity;
}
return updated;
}
void
cogl_matrix_stack_pop (CoglMatrixStack *stack)
{
CoglMatrixEntry *old_top;
CoglMatrixEntry *new_top;
_COGL_RETURN_IF_FAIL (stack != NULL);
old_top = stack->last_entry;
_COGL_RETURN_IF_FAIL (old_top != NULL);
/* To pop we are moving the top of the stack to the old top's parent
* node. The stack always needs to have a reference to the top entry
* so we must take a reference to the new top. The stack would have
* previously had a reference to the old top so we need to decrease
* the ref count on that. We need to ref the new head first in case
* this stack was the only thing referencing the old top. In that
* case the call to cogl_matrix_entry_unref will unref the parent.
*/
/* Find the last save operation and remove it */
/* XXX: it would be an error to pop to the very beginning of the
* stack so we don't need to check for NULL pointer dereferencing. */
for (new_top = old_top;
new_top->op != COGL_MATRIX_OP_SAVE;
new_top = new_top->parent)
;
new_top = new_top->parent;
cogl_matrix_entry_ref (new_top);
cogl_matrix_entry_unref (old_top);
stack->last_entry = new_top;
}
CoglClipStack *
_cogl_clip_stack_push_rectangle (CoglClipStack *stack,
float x_1,
float y_1,
float x_2,
float y_2,
CoglMatrixEntry *modelview_entry,
CoglMatrixEntry *projection_entry,
const float *viewport)
{
CoglClipStackRect *entry;
CoglMatrix modelview;
CoglMatrix projection;
CoglMatrix modelview_projection;
/* Corners of the given rectangle in an clockwise order:
* (0, 1) (2, 3)
*
*
*
* (6, 7) (4, 5)
*/
float rect[] = {
x_1, y_1,
x_2, y_1,
x_2, y_2,
x_1, y_2
};
/* Make a new entry */
entry = _cogl_clip_stack_push_entry (stack,
sizeof (CoglClipStackRect),
COGL_CLIP_STACK_RECT);
entry->x0 = x_1;
entry->y0 = y_1;
entry->x1 = x_2;
entry->y1 = y_2;
entry->matrix_entry = cogl_matrix_entry_ref (modelview_entry);
cogl_matrix_entry_get (modelview_entry, &modelview);
cogl_matrix_entry_get (projection_entry, &projection);
cogl_matrix_multiply (&modelview_projection,
&projection,
&modelview);
/* Technically we could avoid the viewport transform at this point
* if we want to make this a bit faster. */
_cogl_transform_point (&modelview, &projection, viewport, &rect[0], &rect[1]);
_cogl_transform_point (&modelview, &projection, viewport, &rect[2], &rect[3]);
_cogl_transform_point (&modelview, &projection, viewport, &rect[4], &rect[5]);
_cogl_transform_point (&modelview, &projection, viewport, &rect[6], &rect[7]);
/* If the fully transformed rectangle isn't still axis aligned we
* can't handle it using a scissor.
*
* We don't use an epsilon here since we only really aim to catch
* simple cases where the transform doesn't leave the rectangle screen
* aligned and don't mind some false positives.
*/
if (rect[0] != rect[6] ||
rect[1] != rect[3] ||
rect[2] != rect[4] ||
rect[7] != rect[5])
{
entry->can_be_scissor = FALSE;
_cogl_clip_stack_entry_set_bounds ((CoglClipStack *) entry,
rect);
}
else
{
CoglClipStack *base_entry = (CoglClipStack *) entry;
x_1 = rect[0];
y_1 = rect[1];
x_2 = rect[4];
y_2 = rect[5];
/* 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
base_entry->bounds_x0 = COGL_UTIL_NEARBYINT (x_1);
base_entry->bounds_y0 = COGL_UTIL_NEARBYINT (y_1);
base_entry->bounds_x1 = COGL_UTIL_NEARBYINT (x_2);
base_entry->bounds_y1 = COGL_UTIL_NEARBYINT (y_2);
entry->can_be_scissor = TRUE;
}
return (CoglClipStack *) entry;
}
