From: Robert Bragg Date: Tue, 6 Oct 2009 11:36:32 +0000 (+0100) Subject: matrix-stack: more optimization for load_identity case X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b1f9f0a97d1abd4465ed7c7bed1da4ed366491ad;p=profile%2Fivi%2Fclutter.git matrix-stack: more optimization for load_identity case This goes a bit further than the previous patch, and as a special case we now simply represent identity matrices using a boolean, and only lazily initialize them when they need to be modified. --- diff --git a/clutter/cogl/cogl/cogl-matrix-stack.c b/clutter/cogl/cogl/cogl-matrix-stack.c index c581b2d..8b7576d 100644 --- a/clutter/cogl/cogl/cogl-matrix-stack.c +++ b/clutter/cogl/cogl/cogl-matrix-stack.c @@ -35,6 +35,7 @@ typedef struct { CoglMatrix matrix; + gboolean is_identity; /* count of pushes with no changes; when a change is * requested, we create a new state and decrement this */ @@ -54,6 +55,7 @@ struct _CoglMatrixStack /* which state does GL have, NULL if unknown */ CoglMatrixState *flushed_state; + gboolean flushed_identity; }; /* XXX: this doesn't initialize the matrix! */ @@ -64,6 +66,7 @@ _cogl_matrix_state_new (void) state = g_slice_new (CoglMatrixState); state->push_count = 0; + state->is_identity = FALSE; return state; } @@ -71,7 +74,6 @@ _cogl_matrix_state_new (void) static void _cogl_matrix_state_destroy (CoglMatrixState *state) { - g_slice_free (CoglMatrixState, state); } @@ -81,6 +83,18 @@ _cogl_matrix_stack_top (CoglMatrixStack *stack) return stack->stack->data; } +/* 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) @@ -91,7 +105,11 @@ _cogl_matrix_stack_top_mutable (CoglMatrixStack *stack, state = _cogl_matrix_stack_top (stack); if (state->push_count == 0) - return state; + { + if (state->is_identity && initialize) + cogl_matrix_init_identity (&state->matrix); + return state; + } state->push_count -= 1; @@ -99,7 +117,10 @@ _cogl_matrix_stack_top_mutable (CoglMatrixStack *stack, if (initialize) { - new_top->matrix = state->matrix; + if (state->is_identity) + cogl_matrix_init_identity (&new_top->matrix); + else + new_top->matrix = state->matrix; if (stack->flushed_state == state) stack->flushed_state = new_top; @@ -119,7 +140,7 @@ _cogl_matrix_stack_new (void) stack = g_slice_new0 (CoglMatrixStack); state = _cogl_matrix_state_new (); - cogl_matrix_init_identity (&state->matrix); + state->is_identity = TRUE; stack->stack = g_slist_prepend (stack->stack, state); @@ -192,12 +213,22 @@ _cogl_matrix_stack_load_identity (CoglMatrixStack *stack) { CoglMatrixState *state; - /* XXX: In this case an uninitialized top is acceptable */ state = _cogl_matrix_stack_top_mutable (stack, FALSE); - cogl_matrix_init_identity (&state->matrix); - /* mark dirty */ - stack->flushed_state = NULL; + /* NB: Identity matrices are represented by setting + * state->is_identity = TRUE and leaving state->matrix + * uninitialized. + * + * This is done to optimize the heavy usage of + * _cogl_matrix_stack_load_identity by the Cogl Journal. + */ + if (!state->is_identity) + { + state->is_identity = TRUE; + + /* mark dirty */ + stack->flushed_state = NULL; + } } void @@ -212,6 +243,7 @@ _cogl_matrix_stack_scale (CoglMatrixStack *stack, cogl_matrix_scale (&state->matrix, x, y, z); /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -226,6 +258,7 @@ _cogl_matrix_stack_translate (CoglMatrixStack *stack, cogl_matrix_translate (&state->matrix, x, y, z); /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -241,6 +274,7 @@ _cogl_matrix_stack_rotate (CoglMatrixStack *stack, cogl_matrix_rotate (&state->matrix, angle, x, y, z); /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -253,6 +287,7 @@ _cogl_matrix_stack_multiply (CoglMatrixStack *stack, cogl_matrix_multiply (&state->matrix, &state->matrix, matrix); /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -272,6 +307,7 @@ _cogl_matrix_stack_frustum (CoglMatrixStack *stack, z_near, z_far); /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -288,6 +324,7 @@ _cogl_matrix_stack_perspective (CoglMatrixStack *stack, fov_y, aspect, z_near, z_far); /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -306,6 +343,7 @@ _cogl_matrix_stack_ortho (CoglMatrixStack *stack, left, right, bottom, top, z_near, z_far); /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -316,7 +354,17 @@ _cogl_matrix_stack_get (CoglMatrixStack *stack, state = _cogl_matrix_stack_top (stack); - *matrix = state->matrix; + /* NB: identity matrices are lazily initialized because we can often avoid + * initializing them at all if nothing is pushed on top of them since we + * load them using glLoadIdentity() + * + * The Cogl journal typically loads an identiy matrix because it performs + * software transformations, which is why we have optimized this case. + */ + if (state->is_identity) + cogl_matrix_init_identity (matrix); + else + *matrix = state->matrix; } void @@ -325,10 +373,11 @@ _cogl_matrix_stack_set (CoglMatrixStack *stack, { CoglMatrixState *state; - state = _cogl_matrix_stack_top_mutable (stack, TRUE); + state = _cogl_matrix_stack_top_mutable (stack, FALSE); state->matrix = *matrix; /* mark dirty */ stack->flushed_state = NULL; + state->is_identity = FALSE; } void @@ -362,7 +411,17 @@ _cogl_matrix_stack_flush_to_gl (CoglMatrixStack *stack, * than LoadMatrix to send a 2D matrix */ - GE (glLoadMatrixf (cogl_matrix_get_array (&state->matrix))); + if (state->is_identity) + { + if (!stack->flushed_identity) + GE (glLoadIdentity ()); + stack->flushed_identity = TRUE; + } + else + { + GE (glLoadMatrixf (cogl_matrix_get_array (&state->matrix))); + stack->flushed_identity = FALSE; + } stack->flushed_state = state; } @@ -370,5 +429,6 @@ void _cogl_matrix_stack_dirty (CoglMatrixStack *stack) { stack->flushed_state = NULL; + stack->flushed_identity = FALSE; }