From 62a1f1cec488fedae5c96c3423400f12370d9eb5 Mon Sep 17 00:00:00 2001
From: Janne Johansson <icepic.dz@gmail.com>
Date: Thu, 6 Jan 2022 18:04:34 +0000
Subject: [PATCH] Add function to clear pixels in c64-bitmap.c.

---
 src/main/kc/include/c64-bitmap.h | 3 +++
 src/main/kc/lib/c64-bitmap.c     | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/src/main/kc/include/c64-bitmap.h b/src/main/kc/include/c64-bitmap.h
index 322fbd11a..0b840435b 100644
--- a/src/main/kc/include/c64-bitmap.h
+++ b/src/main/kc/include/c64-bitmap.h
@@ -12,5 +12,8 @@ void bitmap_clear(char bgcol, char fgcol);
 /// Plot a single dot in the bitmap
 void bitmap_plot(unsigned int x, char y);
 
+/// Clear a single dot in the bitmap
+void bitmap_unplot(unsigned int x, char y);
+
 /// Draw a line on the bitmap using bresenhams algorithm
 void bitmap_line(unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2);
diff --git a/src/main/kc/lib/c64-bitmap.c b/src/main/kc/lib/c64-bitmap.c
index 9c4c7886f..87539bb8d 100644
--- a/src/main/kc/lib/c64-bitmap.c
+++ b/src/main/kc/lib/c64-bitmap.c
@@ -50,6 +50,12 @@ void bitmap_plot(unsigned int x, char y) {
     *plotter |= bitmap_plot_bit[BYTE0(x)];
 }
 
+void bitmap_unplot(unsigned int x, char y) {
+    char* plotter = (char*) MAKEWORD( bitmap_plot_yhi[y], bitmap_plot_ylo[y] );
+    plotter += ( x & $fff8 );
+    *plotter &= ~(bitmap_plot_bit[BYTE0(x)]);
+}
+
 // Draw a line on the bitmap using bresenhams algorithm
 void bitmap_line(unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2) {
     unsigned int x = x1;