Dots vs. Pixels

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creaothceann
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Re: Dots vs. Pixels

Post by creaothceann »

Interesting... I used the "dots are for timing" because of anomie's timing.txt; I didn't notice that it uses pixels and dots interchangeably. Maybe Nintendo (and hence the video linked above) used "dot" because most people were not familiar with pixels until they had a PC, or a device with a digital display (TV/smartphone). Or it's just a JP-to-EN translation issue.

Interestingly the development manual isn't 100% consistent either: "2133H: [...] An imaginary resolution of 512 (Horizontal) can be created by shifting the SUB screen half dot to the left [...]".

nocash goes one step further and divides the pixels: "the main/sub screen pixels are rendered as half-pixels of the high-resolution image".

SNES AYE wrote: Fri Jan 13, 2023 3:08 pm Except in Modes 5 and 6, where it is 512 dots, right. At least that is what is stated in the video anyway.
512 pixels only applies to BGs though. The horizontal BG positions, the horizontal sprite positions and the windows still use a grid of 256 units. Also, color math treats each pair of pixels as one thing.

The main idea was probably to double the NES's BG rendering speed (one pixel on every phase transition of the 5.369MHz dot clock) and add color math for transparency effects; then some engineer had the idea to optionally output all the pixels early, subscreen pixels first (on a TV screen hi-res mode is actually shifted one pixel to the left compared to low-res mode); in fact it's so early that according to anomie's regs.txt the windows aren't applied correctly: "The 'subscreen' pixel is clipped (by windows) when the main-screen pixel to the LEFT is clipped, not when the one to the RIGHT is clipped as you'd expect. What happens with pixel column 0 is unknown."

jeffythedragonslayer wrote: Fri Jan 13, 2023 4:04 pm I'd prefer an OCR'd copy that's searchable, tbh.
https://archive.org/details/SNESDevManual/book1/
https://archive.org/details/snes_manual1
https://archive.org/details/SFX01SOFTWA ... RE_MANUAL/
My current setup:
Super Famicom ("2/1/3" SNS-CPU-GPM-02) → SCART → OSSC → StarTech USB3HDCAP → AmaRecTV 3.10
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jeffythedragonslayer
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Re: Dots vs. Pixels

Post by jeffythedragonslayer »

creaothceann wrote: Sat Jan 14, 2023 2:36 am The main idea was probably to double the NES's BG rendering speed (one pixel on every phase transition of the 5.369MHz dot clock) and add color math for transparency effects; then some engineer had the idea to optionally output all the pixels early, subscreen pixels first (on a TV screen hi-res mode is actually shifted one pixel to the left compared to low-res mode); in fact it's so early that according to anomie's regs.txt the windows aren't applied correctly: "The 'subscreen' pixel is clipped (by windows) when the main-screen pixel to the LEFT is clipped, not when the one to the RIGHT is clipped as you'd expect. What happens with pixel column 0 is unknown."
Well I think since running things at high frequencies is generally harder, they wanted to emit a pixel on both the rising and falling edge of the clock instead of just one.
Cool.
Pokun
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Re: Dots vs. Pixels

Post by Pokun »

"Pixel art" and "dot art" are two common names of the same type of art, regardless if it's printed or on a video screen.

"Dot matrix LCD" as used by the Game Boy for example is another situation when "dot" is officially used despite LCD technology counting as video and not printing.

In the SNES dev docs "dot" is indeed used for the dots that makes up a picture, so not only a time unit there.
And I mean even if you use it as a time unit, you mean some variation of the time it takes to draw a pixel/dot, so you still ultimately refers to the same thing although indirectly. It's like when you talk about how many "lines" a vblank is despite no lines being drawn during blanking (that's kinda the point of blanking the electron gun), it's only "lines" as a time unit there (and speaking about lines they also have several synonyms used interchangeably: "lines", "scanlines", "rasterlines" and various variations of the three but are really synonymous).

After all, a pixel IS a dot, just a dot that has the role of being a picture element (which is shortened to "pixel"), normally as part of a matrix. They were always used interchangeably since most people would use a common English term like "dot" until they learn of this new term "pixel". And besides "dot" was used for a long time in printing before "pixel" was invented (and still is).



And yeah I'm positive Nintendo made their development manuals as hard to read as possible as a sort of quality-control that sorts out developers that doesn't have enough willpower to get through the damn thing. Just compare it to Hudson's TurboGrafx-16 development manual, it's about as easy to read as a children's picture book. Sega's dev docs are also much easier to read.

SNES AYE wrote: Fri Jan 13, 2023 4:00 pm I'm just about to edit the .pdf to at least remove everything up until Chapter 1 at least, as that appears to be deprecated information that means little today.
If we ignore the historical value there are still some useful info there for a homebrewer. Like how the header works, you may want to keep that part at least.
tepples
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Re: Dots vs. Pixels

Post by tepples »

Another data point: ドット絵 (dotto-e) is Japanese for "pixel art", with the "dotto" part representing English "dot".

The "dots per second" unit of the timing meaning looks like the analog video counterpart of "dots per inch" in printing.
Pokun
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Re: Dots vs. Pixels

Post by Pokun »

Yeah and "dottoe" is also a direct translation of the English "dot picture/art" (where "dotto" is an English loanword).

"Dots per inch" (DPI) is also synonymous to "pixels per inch" (PPI), although the former is more commonly used with a printer's printing resolution and computer mouse resolution, while the latter is more commonly used with image resolution of the unprinted image data.
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