Block Move... with transparency?

Designing hardware and software that uses the VS23S0X0 family of ICs as a 8-bit or SPI SRAM memory or as a Video Controller for generating Composite Video (TV-Out) or driving other kinds of displays.
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Agumander
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Block Move... with transparency?

Post by Agumander » Thu 2020-05-14 8:42

Hi, I'm wondering if it is at all possible to get the Block Move functionality of the VS23S010 to treat a certain pixel color as transparent and "skip" pixels of that color when performing a copy? The Block Move already makes the chip attractive for rendering tilemaps, but it'd also be useful to be able to quickly draw with irregular/nonrectangular boundaries on top of tilemap graphics.

If that doesn't work, since it seems viable to use multiple of this chip in tandem to generate a VGA signal... maybe it'd be feasible to use these with a mux chip to generate layered graphics?

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Panu
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Re: Block Move... with transparency?

Post by Panu » Tue 2020-05-19 11:18

Hi!

No.. and I agree it's a major limitation of using the block move as a blitter engine :(

Personally, I've been toying with the idea of making sprites as lists of rectangles, so there could be gaps, but it has obvious drawbacks. (drawbacks, lol..) I think the most efficient way would be to use the blitter to draw the rectangle and then fill in the transparent pixels.

-Panu
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