- /*\r
---------------------\r
-HORIZONTAL SCROLLING\r
---------------------\r
-Horizontal scrolling is essentially the same as vertical scrolling, all\r
-you do is increment or decrement the VGA offset register by 1 instead of\r
-80 as with vertical scrolling.\r
-\r
-However, horizontal scrolling is complicated by two things\r
-\r
- 1. Incrementing the offset register by one actually scrolls by FOUR\r
- pixels (and there are FOUR planes on the VGA, what a coincidence)\r
-\r
- 2. You can't draw the image off the screen and then scroll it on\r
- because of the way the VGA wraps to the next row every 80 bytes\r
- (80 bytes * 4 planes = 320 pixels), if you tried it, you would\r
- actually be drawing to the other side of the screen (which is\r
- entirely visible)\r
-\r
-I'll solve these problems one at a time.\r
-\r
-Firstly, to get the VGA to scroll by only one pixel you use the horizontal\r
-pixel panning (HPP) register. This register resides at\r
-\r
- PORT: 3C0H\r
- INDEX: 13h\r
-\r
-and in real life, you use it like this\r
-\r
------------------ Pixel Panning ---------------\r
-IN PORT 3DAH (this clears an internal\r
- flip-flop of the VGA)\r
-OUT 13H TO PORT 3C0H\r
-OUT value TO PORT 3C0H (where "value" is the\r
- number of pixels to offset)\r
------------------------------------------------\r
-*/\r
-\r
-//mxSetVirtualScreen(480,360);\r