fastest method to make a parallax side-scrolling game using tiles

Performance Tuning
#21

Interesting bringing up John’s name here…been reading Smartbomb and the telling of the first side scrolling engine that John wrote that was later used for Commander Keen. What was really cool is that John actually just manipulated the CRT’s gun to shift the pixels one column at a time which gave him the fastest rendering, side scrolling engine ever seen on a PC (at the time) with no performance hit in the game engine itself. Sick stuff! It’s actually the way that the first vector games were developed and if you caused to the gun to point outside of a determined field, POOF! Fried display.

Damn! Those were the days…

-Chris

#22

Interesting: i read a totally different version (nothing to do with the CRT’s gun) of the Commander smooth screen scrolling technique in both “Masters of doom” by David Kushner and on http://www.spectrum.ieee.org.

http://www.spectrum.ieee.org/print/1643

[quote] Carmack wrote a so-called graphics display engine that exploited both properties to the full by using a technique that had been originally developed in the 1970s for scrolling over large images, such as satellite photographs. First, he assembled a complete screen in video memory, tile by tile—plus a border one tile wide [see illustration, “Scrolling With the Action” ]. If the player moved one pixel in any direction, the display engine moved the origin of the image it sent to the screen by one pixel in the corresponding direction. No new tiles had to be drawn. When the player’s movements finally pushed the screen image to the outer edge of a border, the engine still did not redraw most of the screen. Instead, it copied most of the existing image—the part that would remain constant—into another portion of video memory. Then it added the new tiles and moved the origin of the screen display so that it pointed to the new image .
[/quote]

#23

Kinda how Amiga scrolling was done and not too dissimilar to the granddaddy of all scrolltasticness, the C64.

Cas :slight_smile:

#24

Not kinda… exactly…
The copper was really the best of all coprocessors the amigas had. Without it, it would have been… mhhh… an atari? :wink: ;D
[flame protection mode on]Well, almost… It had other advantages of course… [flame protection mode off]

#25

You didn’t need to use the Copper chip to adjust the playfield address pointers or scroll registers. I was the the graphics hardware in general that gave you all the cool goodies like dual playfield mode and smooth scrolling. Copper just enhanced it tremendously.

Ah those were the days… remember that book “Mapping the Commodore 64” – where every single BIT of all 64k Bytes was described in detail and every machine was basically the same. You could truly understand the entire machine down to what each bit did. Made for some fancy hacking… like playing with the scrolling registers to trick the video hardware into not drawing the top or bottom screen borders and finding out that “off-screen” sprites would then be visible in the exposed area…