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Old 02 September 2015, 16:00   #43
Code Kitten

Join Date: Aug 2015
Location: Montreal/Canadia
Age: 46
Posts: 1,001
Originally Posted by Samurai_Crow View Post
Stock or acclerated? It's really hard to milk a stock A500 and still use texture mapping, especially with minimal RAM.
The target for my personal projects is the stock A500 with 1MB chip RAM but you are right that texture mapping seems too high a goal unless when done with copper chunky. But just to be clear: Doom like stuff is not in my plans, I just like to think about it.

Originally Posted by eXeler0 View Post
Somehow they did this on the Mega Drive with 64k video ram [ Show youtube player ]
I suppose its a given that a vanilla 500 (or maybe a 500+ and 600 1MB version) would need to rely on ALL the tricks and hacks you can possibly shake out of the 68000, the Copper and the Blitter.
Oh, interesting. But they use a trick not accessible to the Amiga. (Cf below.)

Originally Posted by vulture View Post

I'm not the biggest expert around here, but I see no reason why miggy couldn't match this on the right hands.
There are plenty of reasons actually:
- the MegaDrive uses its 80 hardware sprites to display all animated objects so they are essentially free
- the game seems to make very smart use of tiled graphics: if you look carefully you will notice jaggies (especially on surfaces almost perpendicular to the line of sight) which would not be there if they used proper per pixel texture mapping. This means that they probably have pre rendered tiles containing the various angles and depths of the walls and just choose the most suited tile for each group of 8x8 pixels. This makes updating the screen much faster than a bitmap of the equivalent size.
- the MD is not slowed down by display DMA so the CPU roams free while the whole display is rendered by the VDP, on the Amiga the CPU can only access memory during the cycles not taken by display, copper and blitter. They might be using that free time to generate some of the tiles displayed.
- the MD has chunky-ish pixel definitions so it probably is simpler to do live texture mapping than on planar architecture like the miggy, I am not excluding the possibility that planar texture mapping might be made efficient but for now I certainly have no idea how to do it.

Originally Posted by hooverphonique View Post
something like that could be possible, i guess, presuming you prescaled the height of all wall textures for all lighting levels.
Which would probably take enormous amounts of memory, which is why I think they probably render some of the tiles on the fly from a pre-calculated set of reference depths and angles.

The rendering window is quite small though so maybe something similar can be reached but I'll stay safely skeptical for now.
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