From: Nick Bowler <nbowler@draconx.ca>
Date: Wed, 9 Mar 2022 06:31:27 +0000 (-0500)
Subject: Reduce the amount of redundant drawing in the goal area.
X-Git-Url: http://git.draconx.ca/gitweb/rrace.git/commitdiff_plain/3ac1945c3a0006d33a90a0c2dbee2f2e96e8907d

Reduce the amount of redundant drawing in the goal area.

Same treatment as the game area: on expose events we only need to
redraw the tiles that actually intersect the exposed area.
---

diff --git a/src/motif.c b/src/motif.c
index ef2bd6a..a829cf7 100644
--- a/src/motif.c
+++ b/src/motif.c
@@ -141,7 +141,7 @@ static void proc_new_game(Widget w, XEvent *e, String *argv, Cardinal *argc)
 		shell = XtParent(shell);
 
 	game_reset(&state.board);
-	x11_redraw_goal(&state);
+	x11_redraw_goal(&state, -1);
 	x11_redraw_game(&state, -1);
 	x11_redraw_icon(&state, shell);
 }
diff --git a/src/motif.h b/src/motif.h
index 90ca7af..3e85277 100644
--- a/src/motif.h
+++ b/src/motif.h
@@ -39,7 +39,7 @@ struct app_state {
 void ui_initialize(struct app_state *state, Widget shell);
 void x11_initialize(struct app_state *state, Screen *screen);
 void x11_redraw_icon(struct app_state *state, Widget shell);
-void x11_redraw_goal(struct app_state *state);
+void x11_redraw_goal(struct app_state *state, uint_fast32_t mask);
 void x11_redraw_game(struct app_state *state, uint_fast32_t mask);
 
 #endif
diff --git a/src/motif_ui.c b/src/motif_ui.c
index 5661c1e..4734d05 100644
--- a/src/motif_ui.c
+++ b/src/motif_ui.c
@@ -212,7 +212,7 @@ static void game_resize(Widget w, void *data, void *cb_data)
 static void goal_resize(Widget w, void *data, void *cb_data)
 {
 	if (XtIsRealized(w))
-		x11_redraw_goal(data);
+		x11_redraw_goal(data, -1);
 }
 
 static void do_input_move(struct app_state *state, int x, int y)
@@ -261,24 +261,45 @@ static void game_input(Widget w, void *data, void *cb_data)
 	do_input_move(state, x, y);
 }
 
+/* Figure out which tiles intersect a rectangle. */
+static uint_fast32_t
+expose_mask(int rect_x, int rect_y, int rect_w, int rect_h,
+                                    int tile_w, int tile_h)
+{
+	return board_right(rect_x / tile_w)
+	     & board_below(rect_y / tile_h)
+	     & board_above((rect_y + rect_h - 1) / tile_h)
+	     & board_left((rect_x + rect_w - 1) / tile_w);
+}
+
 static void game_expose(Widget w, void *data, void *cb_data)
 {
 	XmDrawingAreaCallbackStruct *cbs = cb_data;
 	XExposeEvent *e = &cbs->event->xexpose;
-	uint_fast32_t tile_mask;
 	Dimension width, height;
+	uint_fast32_t mask;
 
 	XtVaGetValues(w, XmNwidth, &width, XmNheight, &height, (char *)NULL);
 	if (!(width /= 5) || !(height /= 5))
 		return;
 
-	/* Figure out which tiles have been uncovered */
-	tile_mask  = board_right(e->x / width);
-	tile_mask &= board_below(e->y / height);
-	tile_mask &= board_above((e->y + e->height - 1) / height);
-	tile_mask &= board_left((e->x + e->width - 1) / width);
+	mask = expose_mask(e->x, e->y, e->width, e->height, width, height);
+	x11_redraw_game(data, mask);
+}
+
+static void goal_expose(Widget w, void *data, void *cb_data)
+{
+	XmDrawingAreaCallbackStruct *cbs = cb_data;
+	XExposeEvent *e = &cbs->event->xexpose;
+	Dimension width, height;
+	uint_fast32_t mask;
+
+	XtVaGetValues(w, XmNwidth, &width, XmNheight, &height, (char *)NULL);
+	if (!(width /= 3) || !(height /= 3))
+		return;
 
-	x11_redraw_game(data, tile_mask);
+	mask = expose_mask(e->x, e->y, e->width, e->height, width, height);
+	x11_redraw_goal(data, mask);
 }
 
 void ui_initialize(struct app_state *state, Widget shell)
@@ -302,5 +323,5 @@ void ui_initialize(struct app_state *state, Widget shell)
 
 	state->goal = XtNameToWidget(shell, "*goalCanvas");
 	XtAddCallback(state->goal, XmNresizeCallback, goal_resize, state);
-	XtAddCallback(state->goal, XmNexposeCallback, goal_resize, state);
+	XtAddCallback(state->goal, XmNexposeCallback, goal_expose, state);
 }
diff --git a/src/x11.c b/src/x11.c
index f572616..caf3518 100644
--- a/src/x11.c
+++ b/src/x11.c
@@ -134,7 +134,7 @@ redraw_goal_tile(struct app_state *state, Display *display, Drawable d,
 	return redraw_tile(state, display, d, gp[0], gp[1], gp[2], x, y, w, h);
 }
 
-void x11_redraw_goal(struct app_state *state)
+void x11_redraw_goal(struct app_state *state, uint_fast32_t mask)
 {
 	Display *display = XtDisplay(state->goal);
 	Window window = XtWindow(state->goal);
@@ -142,8 +142,20 @@ void x11_redraw_goal(struct app_state *state)
 	int i;
 
 	XtVaGetValues(state->goal, XmNwidth, &w, XmNheight, &h, (char *)NULL);
-	for (i = 0; i < 9; i++)
-		redraw_goal_tile(state, display, window, i%3, i/3, w/3, h/3);
+	for (i = 0; i < 9; i++) {
+		int x = i%3, y = i/3;
+
+		if (mask & 1) {
+			redraw_goal_tile(state, display, window,
+			                        x, y, w/3, h/3);
+		}
+
+		/*
+		 * Goal bitmaps have a gap of 2 tiles between each row.
+		 * This funny shift will accomodate that.
+		 */
+		mask >>= 1|x;
+	}
 }
 
 /* Render the goal area as the window's icon */