more bug notes

BUGS/Impact Studios - Legend.txt

@@ -0,0 +1,23 @@
+Impact Studio - Legends
+
+BUG: Demo timing runs at half speed, eventually malfunctions and gets
+     stuck in the double-lens section of the demo.
+
+If you run the demo and the bouncing ball and rotozoomer sections run
+slowly, then you are seeing the bug in effect and you should consider
+exiting out because the demo will glitch at the lens section and
+never progress past it.
+
+ - It's not a PIT issue, I tried hacking the PIT to halve the interval.
+   All that does is cause the music to play twice as fast but has no
+   effect on the frame rate.
+
+ - So what IS the demo using for a timer source then? The RTC?
+
+ - I remember this bug first showing up in DOSBox 0.74, previous
+   versions of DOSBox (0.72) ran the demo perfectly fine, which is
+   how I was able to do the demoscene capture for the demoscene
+   collection DVD on scene.org. So what did previous versions of
+   DOSBox do right that DOSBox 0.74 (and therefore DOSBox-X) does
+   wrong?
+

BUGS/VGA emulation errors.txt

@@ -25,6 +25,10 @@ VGA BUG: Exotic VRAM clearing tricks do not work, leaving "garbage" on the scree
        animated VU meters where on real hardware that part of the screen would be
        blank.
 
+ - Impact Studios: Legend
+     - Failure to clear the screen causes 3D dot fields to overdraw into an orange
+       flickering ball.
+
 VGA BUG: Failure to save and restore VGA text screen contents
 
  - Microsoft Windows 95 boot logo