# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1466345739 -7200
# Node ID bface8225ae4ece6093f7d2e448688cd6a0963f9
# Parent  ac90d199ac33897a8852ce6f62830297e74ecdc4
Use the horizontal position counter by itself to manage the pixel buffer.

diff -r ac90d199ac33 -r bface8225ae4 ula.py
--- a/ula.py	Sat Jun 18 00:03:20 2016 +0200
+++ b/ula.py	Sun Jun 19 16:15:39 2016 +0200
@@ -379,7 +379,6 @@
             # Initialise the pixel buffer if appropriate.
 
             if not self.writing_pixels and self.have_pixels:
-                self.pixelpos = 0
                 self.buffer_index = 0
                 self.fill_pixel_buffer()
                 self.writing_pixels = 1
@@ -497,6 +496,8 @@
             self.vsync(1)
 
 
+        self.x += 1
+
 
         # Pixel production.
 
@@ -508,22 +509,19 @@
         # For pixels within the frame, obtain and output the value.
 
         else:
-            self.pixelpos += 1
             self.video.colour = self.buffer[self.buffer_index]
 
             # Scale pixels horizontally, only accessing the next pixel value
             # after the required number of scan positions.
 
-            if self.pixelpos % self.xscale == 0:
+            if self.x % self.xscale == 0:
                 self.buffer_index += 1
 
             # Finish writing pixels.
 
-            if self.pixelpos == PIXEL_POSITIONS:
+            if self.x % PIXEL_POSITIONS == 0:
                 self.writing_pixels = 0
 
-        self.x += 1
-
     def fill_pixel_buffer(self):
 
         """