x11: Improve redraw of empty spaces.

[rrace.git] / src / x11.c

diff --git a/src/x11.c b/src/x11.c
index 0a9bef0a78684ad47ae791c2fd017cc3a1fc0be6..874bfdc57399c4cf6ecf5b7ae2c2d5f2981501ef 100644 (file)
--- a/src/x11.c
+++ b/src/x11.c
@@ -138,6 +138,74 @@ static void draw_tile(struct app_state *state, Display *display, Drawable d,
        XFillRectangle(display, d, state->tile_gc, tx+2, ty+2, tw-4, th-4);
 }
 
+/*
+ * Clear a contiguous rectangle of tiles from top-left (x0, y0) to
+ * bottom-right (x1, y1).
+ */
+static void
+clear_tiles(struct app_state *state, Display *display, Drawable d,
+            int x0, int y0, int x1, int y1, Dimension w, Dimension h)
+{
+       XRectangle r = { x0*w, y0*h, (x1+1)*w, (y1+1)*h };
+
+#if X11_RENDER_DEBUG
+       XSetForeground(display, state->tile_gc, 0xff0000);
+       XFillRectangles(display, d, state->tile_gc, &r, 1);
+       XFlush(display);
+       usleep(70000);
+#endif
+
+       XClearArea(display, d, r.x, r.y, r.width, r.height, 0);
+}
+
+/*
+ * Efficiently clear all the border tiles in the game area.  The mask indicates
+ * which tiles need clearing, but for the border clear it is safe to wipe an
+ * entire row or column of the border using a single XClearArea.
+ *
+ * The idea is to pick whichever row or column has the most tiles to clear,
+ * clear them, and then repeat until none are left (repeats at most 4 times).
+ */
+static void clear_border(struct app_state *state, Display *display, Drawable d,
+                         Dimension w, Dimension h, uint_fast32_t mask)
+{
+       uint_fast32_t best_mask = 0;
+       int best_count = -1;
+       int i, best = -1;
+
+       if (!(mask &= ~GOAL_MASK & 0x1ffffff))
+               return;
+
+       for (i = 0; i < 4; i++) {
+               uint_fast32_t this_mask, tmp;
+               int this_count = 0;
+
+               if (i & 2)
+                       this_mask = board_column(4*(i & 1));
+               else
+                       this_mask = board_row(4*(i & 1));
+
+               /* Count set bits */
+               for (tmp = mask & this_mask; tmp; this_count++)
+                       tmp &= tmp - 1;
+
+               if (this_count > best_count) {
+                       best_count = this_count;
+                       best_mask = this_mask;
+                       best = i;
+               }
+       }
+
+       switch (best) {
+       case 0: clear_tiles(state, display, d, 0, 0, 4, 0, w, h); break;
+       case 1: clear_tiles(state, display, d, 0, 4, 4, 4, w, h); break;
+       case 2: clear_tiles(state, display, d, 0, 0, 0, 4, w, h); break;
+       case 3: clear_tiles(state, display, d, 4, 0, 4, 4, w, h); break;
+       }
+
+       clear_border(state, display, d, w, h, mask & ~best_mask);
+}
+
 static int
 redraw_tile(struct app_state *state, Display *display, Drawable d,
             uint_fast32_t bit0, uint_fast32_t bit1, uint_fast32_t bit2,
@@ -146,6 +214,16 @@ redraw_tile(struct app_state *state, Display *display, Drawable d,
        uint_fast32_t pos = board_position(x, y);
        unsigned char tile = 0;
 
+#if X11_RENDER_DEBUG
+       if (d == XtWindow(state->game) || d == XtWindow(state->goal)) {
+               XRectangle r = { x*w, y*h, w, h };
+               XSetForeground(display, state->tile_gc, 0xff0000);
+               XFillRectangles(display, d, state->tile_gc, &r, 1);
+               XFlush(display);
+               usleep(70000);
+       }
+#endif
+
        if (bit0 & pos) tile |= 1;
        if (bit1 & pos) tile |= 2;
        if (bit2 & pos) tile |= 4;
@@ -177,18 +255,13 @@ void x11_redraw_goal(struct app_state *state, uint_fast32_t mask)
        int i;
 
        XtVaGetValues(state->goal, XtNwidth, &w, XtNheight, &h, (char *)NULL);
+       w /= 3; h /= 3;
+
        for (i = 0; i < 9; i++) {
                int x = i%3, y = i/3;
 
                if (mask & 1) {
-#if X11_RENDER_DEBUG
-                       XRectangle r = { w/3*(i%3), w/3*(i/3), w/3, h/3 };
-                       XSetForeground(display, state->tile_gc, 0xff0000);
-                       XFillRectangles(display, goal, state->tile_gc, &r, 1);
-                       XFlush(display);
-                       usleep(70000);
-#endif
-                       redraw_goal_tile(state, display, goal, x, y, w/3, h/3);
+                       redraw_goal_tile(state, display, goal, x, y, w, h);
                }
 
                /*
@@ -273,15 +346,14 @@ void x11_redraw_game(struct app_state *state, uint_fast32_t mask)
                gp = buf;
        }
 
+       /* Optimize the game end case where the outer frame is cleared */
+       if (((gp[0] | gp[1] | gp[2]) & ~GOAL_MASK) == 0) {
+               clear_border(state, display, game, w, h, mask);
+               mask &= GOAL_MASK;
+       }
+
        for (i = 0; i < 25; i++) {
                if (mask & 1) {
-#if X11_RENDER_DEBUG
-                       XRectangle r = { w*(i%5), w*(i/5), w, h };
-                       XSetForeground(display, state->tile_gc, 0xff0000);
-                       XFillRectangles(display, game, state->tile_gc, &r, 1);
-                       XFlush(display);
-                       usleep(70000);
-#endif
                        redraw_tile(state, display, game,
                                    gp[0], gp[1], gp[2],
                                    i%5, i/5, w, h);