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Games on VME Video Card


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I suppose the idea is ridiculous, but is there a way to retarget game video to a VME video card? For example, can a game like Xenon 2 display on a Matrix CoCo? Automatic switching between desktop and game would be preferrable, but even a custom boot configuration that offered that kind of magic for only a session would be fine.

 

ParanoidLittleMan, I'm blinking at you.

Edited by pixelmischief
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I suppose the idea is ridiculous, but is there a way to retarget game video to a VME video card? For example, can a game like Xenon 2 display on a Matrix CoCo? Automatic switching between desktop and game would be preferrable, but even a custom boot configuration that offered that kind of magic for only a session would be fine.

 

Only programs that use GEM/VDI can be run on other Video cards because GEM/VDI abstracts the graphics.

Games usually write directly to the graphics memory and graphics chip because GEM/VDI is usually too slow for games. To adapt a game to use a video card requires a complete rewrite of the game's graphics engine. It is not only that you need to re-target the video output but probably the graphics layout on a video card is different (Shifter uses 4 interleaved bit planes while graphics cards could use packed byte format) thus also code that prepares the graphics data has to be changed completely to a different graphics layout. Also shifter specific features such as rasters (eg. color gradient in the sky of some platform and racing games) via a timer B interrupt will not work on a graphics card.

 

So in short, it is virtually impossible to run Xenon 2 on a graphics card unless you complete rewrite the game's graphics engine.

 

Robert

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On a second thought, there would be another (more generic) solution and that is to postprocess the game's screen memory each frame. Thus after a games finishes writing its graphics data to memory, there could be a function that reads the screen from memory, converts it to the right format and writes it to the video card. This is similar how Cyrano Jones converted many ST games to the Jaguar where a piece of optimised GPU code converts the screen data to the Jaguar video format (of course there is more to it).

 

However a standard ST is not even fast enough to just copy the memory of a screen each frame let alone convert it while also running the game engine. A 16MHz Mega STE would not help as the memory bandwidth is just too low. I think even a Falcon would not be fast enough to do it on the fly although the DSP could help here. Best chance is a TT that is faster than a Falcon because of its higher clockspeed and memory bandwidth.

 

That a Jaguar can do it on the fly is because the conversion code is running on a fast RISC processor parallel to the 68000 and the memory bandwidth is also much higher than an ST.

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