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Post by turboxray on Oct 2, 2021 18:48:19 GMT
This needs to get more love:
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DutchDimension
Punkic Cyborg
Posts: 122
Homebrew skills: Pixel, 2D and 3D art
Fave PCE Shooter: Override
Fave PCE Platformer: Mizbak's Adventure
Fave PCE Game Overall: Too many to choose from
Fave PCE RPG: Ys series
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Post by DutchDimension on Oct 3, 2021 6:54:39 GMT
That's looking great for a mere demo!
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4lorn
Deep Blooper
Posts: 27
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Post by 4lorn on Oct 3, 2021 12:56:17 GMT
This is pretty good. Is it something similar to Sega' Super Scaler effect, or entirely different?
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Post by turboxray on Oct 4, 2021 3:26:14 GMT
This is pretty good. Is it something similar to Sega' Super Scaler effect, or entirely different? No. It's literally snes mode 7 done in software. I.e. a rotation and scaling pass on a bitmap.
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4lorn
Deep Blooper
Posts: 27
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Post by 4lorn on Oct 4, 2021 9:24:53 GMT
... Wow. It's even more amazing, then.
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gilbot
Punkic Cyborg
Posts: 137
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Post by gilbot on Oct 4, 2021 13:29:02 GMT
The resolution is so low though. I think it's using either 8x8 pixel(i.e. single tile) or 4x4 pixel(i.e. 2x2 dots per tile) to "render" the plane (never counted the squares). This is like how Steve Woz introduced the low res modes in the Apple ][s, thinking they might be useful in fast action games (too bad it's not widely adopted). At least it showed what's really practical, not like what Flight Plan did in Metamor Jupiter (which IMO was an average at best shooter and tried to do "every Super Famicom effect" which was not even impressive as a tech. demo, at least the raster effect colony stage did look great though). If not for the "real mode 7" effect I think Chris' demo might look even better.
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Post by turboxray on Oct 4, 2021 15:22:13 GMT
The problem, for any of these old systems, isn't so much the speed/capability of the processor, but rather that they don't have a bitmap 'byte' size linear pixel oriented bitmap destination buffer to work on. Working with packed/linear pixels makes things very fast (ala 256 color modes of PCs BITD). So the author here is using the tilemap itself as a linear pixel bitmap buffer.. because one write means one pixel. Although in detail, you have a byte represent two pixels - but the same idea. That gives a chunk res of 64xYY (YY being however you divide up the map). I think this example the effective res is a 4x4 pixel. That gives them room to double buffer on the tilemap, not how have to render to ram first.. but render directly into vram. It easily allows 16 colors per 4x4 pixel, an shading if you palettes on top of that.
Gasega68k has a similar demo on the Genesis, but at a higher res (2x2). The PCE can do a similar 2x2 res using 512x224x16colors (with palette fade per two pixels) linear pixel mode. Of course that means you halve the relative sprite pixel coverage across the screen. You can also double buffer the bitmap (tilemap) by writing to a completely separate section of vram, and then have the vDMA copy it over. That gives a 128x128 area with pixel size being 2x2, but if you do as Gasega68k does, you make that a 128x60-ish window area, and have the rest of the tilemap as normal for the top part (the background). And because of the VDP increment reg, you can either write in horizontal or vertical strips at a time.
With the above method on the supergrafx, you can have 128x60x241 colors @ 2x2 scaled pixels (and still have palette mapping for shading), or have it configured as 256x60x16 colors @ 1x2 scaled pixels (because of two tilemaps on top of each other interleaving).
The demo video I posted looks like it's about 25+fps by eye-balling it, and if I interpret the hex value correctly in the status bar.. it's running at 27fps.
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