mutter/clutter/cogl/common/cogl-matrix-stack.c
Havoc Pennington 08932584b5 Virtualize GL matrix operations and use a client-side matrix when GL is indirect
This is useful because sometimes we need to get the current matrix, which
is too expensive when indirect rendering.

In addition, this virtualization makes it easier to clean up the API in
the future.
2009-03-12 18:32:45 +00:00

328 lines
7.4 KiB
C

/*
* Clutter COGL
*
* A basic GL/GLES Abstraction/Utility Layer
*
* Authored By Havoc Pennington <hp@pobox.com> for litl
*
* Copyright (C) 2009 OpenedHand
*
* 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl.h"
#include "cogl-context.h"
#include "cogl-internal.h"
#include "cogl-matrix-stack.h"
typedef struct {
CoglMatrix matrix;
/* count of pushes with no changes; when a change is
* requested, we create a new state and decrement this
*/
int push_count;
} CoglMatrixState;
/**
* CoglMatrixStack:
*
* Stores a cogl-side matrix stack, which we use as a cache
* so we can get the matrix efficiently when using indirect
* rendering.
*/
struct _CoglMatrixStack
{
GSList *stack;
/* which state does GL have, NULL if unknown */
CoglMatrixState *flushed_state;
};
static CoglMatrixState*
_cogl_matrix_state_new (void)
{
CoglMatrixState *state;
state = g_slice_new0 (CoglMatrixState);
/* load identity */
cogl_matrix_init_identity (&state->matrix);
/* state->push_count defaults to 0 */
return state;
}
static void
_cogl_matrix_state_destroy (CoglMatrixState *state)
{
g_slice_free (CoglMatrixState, state);
}
static CoglMatrixState*
_cogl_matrix_stack_top (CoglMatrixStack *stack)
{
return stack->stack->data;
}
static CoglMatrixState*
_cogl_matrix_stack_top_mutable (CoglMatrixStack *stack)
{
CoglMatrixState *state;
CoglMatrixState *new_top;
state = _cogl_matrix_stack_top (stack);
if (state->push_count == 0)
return state;
state->push_count -= 1;
new_top = _cogl_matrix_state_new ();
new_top->matrix = state->matrix;
if (stack->flushed_state == state)
{
stack->flushed_state = new_top;
}
stack->stack =
g_slist_prepend (stack->stack,
new_top);
return new_top;
}
CoglMatrixStack*
_cogl_matrix_stack_new (void)
{
CoglMatrixStack *stack;
CoglMatrixState *state;
stack = g_slice_new0 (CoglMatrixStack);
state = _cogl_matrix_state_new ();
stack->stack =
g_slist_prepend (stack->stack,
state);
return stack;
}
void
_cogl_matrix_stack_destroy (CoglMatrixStack *stack)
{
while (stack->stack)
{
CoglMatrixState *state;
state = stack->stack->data;
_cogl_matrix_state_destroy (state);
stack->stack =
g_slist_delete_link (stack->stack,
stack->stack);
}
g_slice_free (CoglMatrixStack, stack);
}
void
_cogl_matrix_stack_push (CoglMatrixStack *stack)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top (stack);
/* we lazily create a new stack top if someone changes the matrix
* while push_count > 0
*/
state->push_count += 1;
}
void
_cogl_matrix_stack_pop (CoglMatrixStack *stack)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top (stack);
if (state->push_count > 0)
{
state->push_count -= 1;
}
else
{
if (stack->stack->next == NULL)
{
g_warning ("Too many matrix pops");
return;
}
if (stack->flushed_state == state)
{
stack->flushed_state = NULL;
}
stack->stack =
g_slist_delete_link (stack->stack,
stack->stack);
_cogl_matrix_state_destroy (state);
}
}
void
_cogl_matrix_stack_load_identity (CoglMatrixStack *stack)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top_mutable (stack);
cogl_matrix_init_identity (&state->matrix);
/* mark dirty */
stack->flushed_state = NULL;
}
void
_cogl_matrix_stack_scale (CoglMatrixStack *stack,
float x,
float y,
float z)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top_mutable (stack);
cogl_matrix_scale (&state->matrix, x, y, z);
/* mark dirty */
stack->flushed_state = NULL;
}
void
_cogl_matrix_stack_translate (CoglMatrixStack *stack,
float x,
float y,
float z)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top_mutable (stack);
cogl_matrix_translate (&state->matrix, x, y, z);
/* mark dirty */
stack->flushed_state = NULL;
}
void
_cogl_matrix_stack_rotate (CoglMatrixStack *stack,
float angle,
float x,
float y,
float z)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top_mutable (stack);
cogl_matrix_rotate (&state->matrix, angle, x, y, z);
/* mark dirty */
stack->flushed_state = NULL;
}
void
_cogl_matrix_stack_multiply (CoglMatrixStack *stack,
const CoglMatrix *matrix)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top_mutable (stack);
cogl_matrix_multiply (&state->matrix, &state->matrix, matrix);
/* mark dirty */
stack->flushed_state = NULL;
}
void
_cogl_matrix_stack_get (CoglMatrixStack *stack,
CoglMatrix *matrix)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top (stack);
*matrix = state->matrix;
}
void
_cogl_matrix_stack_set (CoglMatrixStack *stack,
const CoglMatrix *matrix)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top_mutable (stack);
state->matrix = *matrix;
/* mark dirty */
stack->flushed_state = NULL;
}
void
_cogl_matrix_stack_frustum (CoglMatrixStack *stack,
float left,
float right,
float bottom,
float top,
float z_near,
float z_far)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top_mutable (stack);
cogl_matrix_frustum (&state->matrix,
left, right, bottom, top,
z_near, z_far);
/* mark dirty */
stack->flushed_state = NULL;
}
void
_cogl_matrix_stack_flush_to_gl (CoglMatrixStack *stack,
GLenum gl_mode)
{
CoglMatrixState *state;
state = _cogl_matrix_stack_top (stack);
if (stack->flushed_state == state)
return;
/* NOTE we assume caller was in MODELVIEW mode */
if (gl_mode != GL_MODELVIEW)
GE (glMatrixMode (gl_mode));
/* In theory it might help the GL implementation if we used our
* local analysis of the matrix and called Translate/Scale rather
* than LoadMatrix to send a 2D matrix
*/
GE (glLoadMatrixf (cogl_matrix_get_array (&state->matrix)));
stack->flushed_state = state;
if (gl_mode != GL_MODELVIEW)
GE (glMatrixMode (GL_MODELVIEW));
}