From fc23334e54b0b90d2f00b017a03cf47b70dc71aa Mon Sep 17 00:00:00 2001
From: Zhigang Gong <zhigang.gong@gmail.com>
Date: Fri, 1 Jul 2011 23:51:42 +0800
Subject: [PATCH] glamor: Optimize fallback case for the polylines.

When fallback to cpu for the polylines procedure, we can just download
required region to CPU rather than to download the whole pixmap. This
significant improve the performance if we have to fallback, for example
 do non-solid filling in the game Mines.

Signed-off-by: Zhigang Gong <zhigang.gong@gmail.com>
---
 glamor/glamor_polylines.c | 73 +++++++++++++++++++++++++++++++++++----
 1 file changed, 67 insertions(+), 6 deletions(-)

diff --git a/glamor/glamor_polylines.c b/glamor/glamor_polylines.c
index 914961161..3fdb26426 100644
--- a/glamor/glamor_polylines.c
+++ b/glamor/glamor_polylines.c
@@ -49,6 +49,13 @@ glamor_poly_lines(DrawablePtr drawable, GCPtr gc, int mode, int n,
     xRectangle *rects;
     int x1, x2, y1, y2;
     int i;
+    int x_min = MAXSHORT;
+    int x_max = MINSHORT;
+    int y_min = MAXSHORT;
+    int y_max = MINSHORT;
+    DrawablePtr temp_dest;
+    PixmapPtr temp_pixmap;
+    GCPtr temp_gc;
     /* Don't try to do wide lines or non-solid fill style. */
     if (gc->lineWidth != 0) {
 	/* This ends up in miSetSpans, which is accelerated as well as we
@@ -103,16 +110,70 @@ glamor_poly_lines(DrawablePtr drawable, GCPtr gc, int mode, int n,
     return;
 
 fail:
+   for(i = 0; i < n; i++)
+      {
+        if (x_min > points[i].x)
+          x_min = points[i].x;
+        if (x_max < points[i].x)
+          x_max = points[i].x;
+
+        if (y_min > points[i].y)
+          y_min = points[i].y;
+        if (y_max < points[i].y)
+          y_max = points[i].y;
+      }
+
+    temp_pixmap = drawable->pScreen->CreatePixmap(drawable->pScreen,
+                                                  x_max - x_min + 1, y_max - y_min + 1,
+                                                  drawable->depth,
+                                                  0);
+    if (temp_pixmap) {
+      temp_dest = &temp_pixmap->drawable;
+      temp_gc = GetScratchGC(temp_dest->depth, temp_dest->pScreen);
+      ValidateGC(temp_dest, temp_gc);
+      for(i = 0; i < n; i++)
+        {
+           points[i].x -= x_min;
+           points[i].y -= y_min;
+        }
+      (void)glamor_copy_area(drawable,
+			     temp_dest,
+		             temp_gc,
+			     x_min, y_min,
+			     x_max - x_min + 1, y_max - y_min + 1,
+			     0, 0);
+    
+    } 
+    else 
+      temp_dest = drawable;
+
     if (gc->lineWidth == 0) {
-	if (glamor_prepare_access(drawable, GLAMOR_ACCESS_RW)) {
+	if (glamor_prepare_access(temp_dest, GLAMOR_ACCESS_RW)) {
 	    if (glamor_prepare_access_gc(gc)) {
-		fbPolyLine(drawable, gc, mode, n, points);
+		fbPolyLine(temp_dest, gc, mode, n, points);
 		glamor_finish_access_gc(gc);
 	    }
-	    glamor_finish_access(drawable);
+	    glamor_finish_access(temp_dest);
 	}
-	return;
-    }
+    } 
+    else {
     /* fb calls mi functions in the lineWidth != 0 case. */
-    fbPolyLine(drawable, gc, mode, n, points);
+      fbPolyLine(drawable, gc, mode, n, points);
+    }
+    if (temp_dest != drawable) {
+      (void)glamor_copy_area(temp_dest,
+			     drawable,
+		             temp_gc,
+			     0, 0,
+			     x_max - x_min + 1, y_max - y_min + 1,
+			     x_min, y_min);
+      drawable->pScreen->DestroyPixmap(temp_pixmap);
+      for(i = 0; i < n; i++)
+        {
+           points[i].x += x_min;
+           points[i].y += y_min;
+        }
+ 
+      FreeScratchGC(temp_gc);
+    }
 }