From e48e60b3e072d9c6974343db07ebda24e1bcb123 Mon Sep 17 00:00:00 2001
From: Jens Arnold <amiconn@rockbox.org>
Date: Mon, 20 Feb 2006 19:15:46 +0000
Subject: Faster filled triangle drawing for colour targets and greyscale
 iPods.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8751 a1c6a512-1295-4272-9138-f99709370657
---
 apps/plugins/lib/xlcd.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/apps/plugins/lib/xlcd.c b/apps/plugins/lib/xlcd.c
index 8f26330470..9b03a16b6a 100644
--- a/apps/plugins/lib/xlcd.c
+++ b/apps/plugins/lib/xlcd.c
@@ -35,7 +35,78 @@ void xlcd_init(struct plugin_api* newrb)
     local_rb = newrb;
 }
 
-/* draw a filled triangle */
+#if (LCD_DEPTH >= 8) || (LCD_PIXELFORMAT == HORIZONTAL_PACKING)
+/* draw a filled triangle, using horizontal lines for speed */
+void xlcd_filltriangle(int x1, int y1, int x2, int y2, int x3, int y3)
+{
+    int x, y;
+    long fp_x1, fp_x2, fp_dx1, fp_dx2;
+
+    /* sort vertices by increasing y value */
+    if (y1 > y3)
+    {
+        if (y2 < y3)       /* y2 < y3 < y1 */
+        {
+            x = x1; x1 = x2; x2 = x3; x3 = x;
+            y = y1; y1 = y2; y2 = y3; y3 = y;
+        }
+        else if (y2 > y1)  /* y3 < y1 < y2 */
+        {
+            x = x1; x1 = x3; x3 = x2; x2 = x;
+            y = y1; y1 = y3; y3 = y2; y2 = y;
+        }
+        else               /* y3 <= y2 <= y1 */
+        {
+            x = x1; x1 = x3; x3 = x;
+            y = y1; y1 = y3; y3 = y;
+        }
+    }
+    else
+    {
+        if (y2 < y1)       /* y2 < y1 <= y3 */
+        {
+            x = x1; x1 = x2; x2 = x;
+            y = y1; y1 = y2; y2 = y;
+        }
+        else if (y2 > y3)  /* y1 <= y3 < y2 */
+        {
+            x = x2; x2 = x3; x3 = x;
+            y = y2; y2 = y3; y3 = y;
+        }
+        /* else already sorted */
+    }
+
+    if (y1 < y3)  /* draw */
+    {
+        fp_dx1 = ((x3 - x1) << 16) / (y3 - y1);
+        fp_x1  = (x1 << 16) + (1<<15) + (fp_dx1 >> 1);
+
+        if (y1 < y2)  /* first part */
+        {   
+            fp_dx2 = ((x2 - x1) << 16) / (y2 - y1);
+            fp_x2  = (x1 << 16) + (1<<15) + (fp_dx2 >> 1);
+            for (y = y1; y < y2; y++)
+            {
+                local_rb->lcd_hline(fp_x1 >> 16, fp_x2 >> 16, y);
+                fp_x1 += fp_dx1;
+                fp_x2 += fp_dx2;
+            }
+        }
+        if (y2 < y3)  /* second part */
+        {
+            fp_dx2 = ((x3 - x2) << 16) / (y3 - y2);
+            fp_x2 = (x2 << 16) + (1<<15) + (fp_dx2 >> 1);
+            for (y = y2; y < y3; y++)
+            {
+                local_rb->lcd_hline(fp_x1 >> 16, fp_x2 >> 16, y);
+                fp_x1 += fp_dx1;
+                fp_x2 += fp_dx2;
+            }
+        }
+    }
+}            
+#else /* (LCD_DEPTH < 8) && (LCD_PIXELFORMAT == VERTICAL_PACKING) */
+/* draw a filled triangle, using vertical lines for speed */
 void xlcd_filltriangle(int x1, int y1, int x2, int y2, int x3, int y3)
 {
     int x, y;
@@ -104,6 +175,7 @@ void xlcd_filltriangle(int x1, int y1, int x2, int y2, int x3, int y3)
         }
     }
 }
+#endif /* LCD_DEPTH, LCD_PIXELFORMAT */
 
 #if LCD_DEPTH >= 8
 
-- 
cgit