From 0e26f488f6c85dff230fc6c759b1eaab272f442f Mon Sep 17 00:00:00 2001
From: Adam Greenwood-Byrne <adam@isometim.es>
Date: Wed, 24 Mar 2021 17:28:54 +0000
Subject: [PATCH] Fixed a bug in wflipb.c, exercsied in examples/wgt19.c

---
 part12-wgt/examples/wgt19.c | 111 ++++++++++++++++++++++++++++++++++++
 part12-wgt/wflipb.c         |   2 +-
 2 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 part12-wgt/examples/wgt19.c

diff --git a/part12-wgt/examples/wgt19.c b/part12-wgt/examples/wgt19.c
new file mode 100644
index 0000000..8ee962a
--- /dev/null
+++ b/part12-wgt/examples/wgt19.c
@@ -0,0 +1,111 @@
+#include "wgtspr.h"
+#include "include/mem.h"
+#include "include/multicore.h"
+
+// ######## REQUIRED FUNCTIONS ########
+
+unsigned long state0 = 1000;
+unsigned long state1 = 2000;
+
+unsigned long rand(void)
+{
+    unsigned long s1 = state0;
+    unsigned long s0 = state1;
+
+    state0 = s0;
+    s1 ^= s1 << 23;
+    s1 ^= s1 >> 17;
+    s1 ^= s0;
+    s1 ^= s0 >> 26;
+    state1 = s1;
+
+    return state0 + state1;
+}
+
+// ######## STUB FUNCTIONS ########
+
+unsigned int kb = 0;
+
+unsigned int kbhit(void) {
+    kb++;
+    return kb / 500;
+}
+
+void getch(void) {
+    wait_msec(0x500000);
+    kb = 0;
+}
+
+// ######## WGT EXAMPLES ########
+
+void wgt19()
+{
+  block screen1;	/* one virtual screen */
+  block sprites[10];	/* An array of blocks to load the sprites into.
+			   Version 4.0 allows for any number to be
+			   loaded in, as long as you pass the same size
+			   of the array to the wloadsprites and wfreesprites
+			   commands. */
+  int y, sp;
+  color palette[256];
+
+  set_clock_rate(get_max_clock());
+  mem_init();
+  vga256 ();                    /* Initializes WGT system       */
+
+  start_core2(minit);           // Start the comms engine (core 2)
+  while (!comms_up);            // Wait for comms up
+
+  extern unsigned char _binary_bin_space_spr_start[];
+  wloadsprites (palette, &_binary_bin_space_spr_start[0], sprites, 0, 9);
+  /* load first 10 sprites */
+  wsetpalette (0, 255, palette);
+
+  screen1 = wnewblock (0, 0, 319, 199);
+  wsetscreen (screen1);
+
+  sp = 1;	  		/* sprites always start at 1 in the array */
+
+  msetbounds (0, 0, 160, 199);
+
+  do {
+    for (y = 0; y < 200; y++)
+      {
+       wsetcolor (vgapal[y]);
+       wfline (0, y, 319, y); /* clear the screen by drawing horz lines (fast) */
+      }
+
+    if (sprites[sp] != NULL)
+      {
+       wputblock (mx, my, sprites[sp], 1);	/* put the block using xray mode at mouse position */
+
+       wflipblock (sprites[sp], 0); /* flip the sprite vertically */
+       wresize (mx - 20, my + 50, mx + 20, my + 90, sprites[sp], 1);
+       /* resize the sprite using xray mode just below the first one */
+
+       wflipblock (sprites[sp], 0); /* flip it back to normal */
+      }
+
+    wcopyscreen (0, 0, 160, 199, screen1, 0, 0, NULL);  /* copy half the screen */
+
+    if (mx == 0)  /* Show the next sprite */
+      {
+       sp++;
+       if (sp > 9)
+	 sp = 1;
+       //noclick ();
+      }
+
+  } while (1);
+
+  msetbounds (0, 0, 319, 199);
+  mdeinit ();                   /* Deinitialize the mouse handler */
+  wfreeblock (screen1);
+  wfreesprites (sprites, 0, 9);  /* frees all sprites in that array */
+}
+
+void main()
+{
+    wgt19();
+    while (1);
+}
diff --git a/part12-wgt/wflipb.c b/part12-wgt/wflipb.c
index 8a10860..3d45960 100644
--- a/part12-wgt/wflipb.c
+++ b/part12-wgt/wflipb.c
@@ -14,7 +14,7 @@ void wflipblock (block image, short direction)
   height = wgetblockheight (image);
   temp = malloc (width*4);
   temp2 = malloc (width*4);
-  image += 4;
+  image += 2;
 
   if  (direction == 1)                       /* Horizontal flip */
   {