/* XXX:
* Operations like scale, translate, rotate etc need to have an
* initialized state->matrix to work with, so they will pass
* initialize = TRUE.
*
* _cogl_matrix_stack_load_identity and _cogl_matrix_stack_set on the
* other hand don't so they will pass initialize = FALSE
*
* NB: Identity matrices are represented by setting
* state->is_identity=TRUE in which case state->matrix will be
* uninitialized.
*/
static CoglMatrixState *
_cogl_matrix_stack_top_mutable (CoglMatrixStack *stack,
gboolean initialize)
{
CoglMatrixState *state;
CoglMatrixState *new_top;
state = _cogl_matrix_stack_top (stack);
if (state->push_count == 0)
{
if (state->is_identity && initialize)
cogl_matrix_init_identity (&state->matrix);
return state;
}
state->push_count -= 1;
g_array_set_size (stack->stack, stack->stack->len + 1);
new_top = &g_array_index (stack->stack, CoglMatrixState,
stack->stack->len - 1);
_cogl_matrix_state_init (new_top);
if (initialize)
{
if (state->is_identity)
cogl_matrix_init_identity (&new_top->matrix);
else
new_top->matrix = state->matrix;
}
return new_top;
}
CoglMatrixStack*
_cogl_matrix_stack_new (void)
{
CoglMatrixStack *stack;
CoglMatrixState *state;
stack = g_slice_new0 (CoglMatrixStack);
stack->stack = g_array_sized_new (FALSE, FALSE,
sizeof (CoglMatrixState), 10);
g_array_set_size (stack->stack, 1);
state = &g_array_index (stack->stack, CoglMatrixState, 0);
_cogl_matrix_state_init (state);
state->is_identity = TRUE;
stack->age = 0;
return _cogl_matrix_stack_object_new (stack);
}