Search found 3134 matches

by psycopathicteen
Wed Mar 13, 2024 11:52 am
Forum: SNESdev
Topic: S-PPU and the V9990 (also MSX3)
Replies: 14
Views: 3493

Re: S-PPU and the V9990 (also MSX3)

Was the YJK color space a bug? It looks like they tried to implement a hardware YUV color mode but accidentally switched blue with green.
by psycopathicteen
Sun Feb 25, 2024 7:17 pm
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

The way it works, if I'm not mistaken, is that the S-PPU scans OAM during each active scanline and collects the first 32 entries that intersect the subsequent line. Then during HBlank, it works backward through that list and renders up to 34 8-pixel tile slivers to a line buffer, which is then rend...
by psycopathicteen
Wed Feb 14, 2024 9:54 am
Forum: SNESdev
Topic: Two separate moving objects out of one background?
Replies: 23
Views: 1822

Re: Two separate moving objects out of one background?

I wonder if the 3rd layer and the scrolling parts of the 4th layer are made with sprites considering that they don't have a mosaic effect on them.
by psycopathicteen
Wed Feb 14, 2024 8:48 am
Forum: SNESdev
Topic: What's the real cycle timing for LDA abs,x?
Replies: 8
Views: 758

Re: What's the real cycle timing for LDA abs,x?

I checked all the WDC manuals and they say nothing about an extra cycle being added when index registers are in 16-bit mode datasheet page 24 note 3 That's not what I was talking about. I know that it takes 5 cycles when the accumulator is in 16-bit mode. The question was whether or not it's 6 cycl...
by psycopathicteen
Sun Feb 11, 2024 7:37 am
Forum: SNESdev
Topic: What's the real cycle timing for LDA abs,x?
Replies: 8
Views: 758

Re: What's the real cycle timing for LDA abs,x?

A few years ago superfamicom.wiki was the only website that didn't have that detail, now it's the only one that does.

BSNES does 6 cycles, from looking at it's debugger trace.
by psycopathicteen
Sat Feb 10, 2024 9:24 pm
Forum: SNESdev
Topic: What's the real cycle timing for LDA abs,x?
Replies: 8
Views: 758

What's the real cycle timing for LDA abs,x?

With both index and accumulator being in 16-bit mode, first it was 5 cycles, then it was 6 cycles, now every document says it's 5 cycles again? I checked all the WDC manuals and they say nothing about an extra cycle being added when index registers are in 16-bit mode, only when they are crossing pag...
by psycopathicteen
Mon Feb 05, 2024 9:30 am
Forum: SNESdev
Topic: Two separate moving objects out of one background?
Replies: 23
Views: 1822

Re: Two separate moving objects out of one background?

I think 93143 (or somebody else) said a while back that vertical screen splits are also possible, but you need to find a way to cover up the glitch in the middle of the screen.
by psycopathicteen
Sat Feb 03, 2024 1:32 pm
Forum: SNESdev
Topic: Max sprites on-screen using the following approach . . .
Replies: 9
Views: 935

Re: Max sprites on-screen using the following approach . . .

What is the sPPU doing with OAM while it's fetching the first 2 tiles of the background layer? Is the OAM address still locked during that period?
by psycopathicteen
Sat Feb 03, 2024 1:07 pm
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

Here's an updated version that uses 8-pixel tall screen segments instead of 16-pixel tall screen segments.   drop_out_backmost_sprites: rep #$30 lda {sprite_number} bne + rtl +; stz.w {sprites_per_screen_segment} stz.w {sprites_per_screen_segment}+2 stz.w {sprites_per_screen_segment}+4 stz.w {sprite...
by psycopathicteen
Sat Feb 03, 2024 8:09 am
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

I did cycle counts and I found out that it's faster without the first loop. Worst case scenario (128 32x32 sprites) is ~14,000 cycles with the first loop, and ~10,000 cycles without the first loop.
by psycopathicteen
Fri Feb 02, 2024 8:55 am
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

Some sprites have to be in front of other sprites.
by psycopathicteen
Thu Feb 01, 2024 6:54 pm
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Trying to make the backmost sprites drop out first.

I wrote this routine to detect when there are too many sprites on a scanline, and drop out the back-most sprites, so that the sPPU doesn't drop the front-most sprites like it usually does. There are two loops in the routine. The first loop drops out 32x32 sprites when there are more than 8 32x32 spr...
by psycopathicteen
Wed Jan 24, 2024 8:09 pm
Forum: SNESdev Homebrew Projects
Topic: Terrific Audio Driver
Replies: 16
Views: 3723

Re: Terrific Audio Driver

If you're ever planning on implementing a Gaussian pre-emphasis filter, you can use this formula for the convolution window:

y = a*b^|x|
a = 16/sqrt(70)
b = (16*sqrt(70) - 163)/93
by psycopathicteen
Sat Jan 13, 2024 11:08 am
Forum: SNESdev Homebrew Projects
Topic: Terrific Audio Driver
Replies: 16
Views: 3723

Re: Terrific Audio Driver

What's the difference between old, anomie and multiple?
by psycopathicteen
Sun Dec 31, 2023 9:39 pm
Forum: SNESdev Homebrew Projects
Topic: Terrific Audio Driver
Replies: 16
Views: 3723

Re: Terrific Audio Driver

When I click on the new project button, it waits for 2 seconds and then disappears.

Version 0.3 works on my computer though. I don't know why version 0.4 didn't.