Search found 96 matches

by none
Sat Aug 06, 2022 6:55 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

The games that use the same tables for A/B and C/D, are they perspectively accurate or are they distorted? Are they more accurate to slope-based perspective (straight lines remain straight), or by angle-based perspective (straight lines get curved)? If done right they are accurately a perspective, ...
by none
Fri Aug 05, 2022 1:40 am
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

CX and CY are supposed to be both the camera and m7x and m7y. Just so you know, I didn't test this out. Just did a ton of math problems until I got to this solution. Where do you download the thing to try it out? Ah, ok. That makes sense. It is a really nice solution. You can copy and paste the JS ...
by none
Thu Aug 04, 2022 5:53 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

Here is a formula for Mode-7 using only A, C and BGY: X = A(SX + BGX - CX) + B(SY + BGY - CY) + CX Y = C(SX + BGX - CX) + D(SY + BGY - CY) + CY P = Cz/(cos(b)d - sin(b)(Sy - 112)) BGX = Cx - 128 BGY = P*(cos(b)(Sy - 112) + sin(b)d) - Sy + Cy A = P*cos(a) B = sin(a) C = -P*sin(a) D = cos(a) This see...
by none
Thu Aug 04, 2022 2:50 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

Is the actual range of inputs for all camera settings narrow enough to generically just be a table of reciprocals? It seems to be, with some compromises, you need to weigh precision against view distance, and table size. However now that I think more about the hardware division approach that one do...
by none
Thu Aug 04, 2022 1:48 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

However, actually I think this kind of interpolation would not buy a real benefit on snes hardware because everything has to be done with lookup tables anyway (because mode7 hardware is busy so no hardware multiplication or division). Even if hardware was used, performance isn't much worse with div...
by none
Thu Aug 04, 2022 1:28 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

here's yet another iteration that has the lookup tables simulated. the multiplication table would need to be quite big, but you can get away with the reciprocal table only having a few entries (1024 in this case). also both tables can be used for general purpose. i've also tried combining the tables...
by none
Wed Aug 03, 2022 2:18 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

I've restructured my code a little, in this version it should be better visible what actually needs to be computed per scanline. Also I tried to simulate the precision limitations when doing the math with 16bit fixed point precision. With some optimizations applied, now it looks very close to what a...
by none
Tue Aug 02, 2022 7:01 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

I don't get the GBA tutorial either, but I don't think he's was doing the same thing that I was doing, because he's talking alot about it in terms of rotating and zooming the bg to make it fit. About positioning the sprites, I'd go about it much the same way you did. Basically all the conversion fro...
by none
Tue Aug 02, 2022 3:52 pm
Forum: SNESdev
Topic: Two simultaneous mode 7 textures?
Replies: 39
Views: 1267

Re: Kulor's Guide to Mode 7 Perspective Planes

Terranigma had a nice solution for faking a sky

https://youtu.be/Nsb2eFt7BCs?t=4290
by none
Tue Aug 02, 2022 3:45 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

FOV can be adjusted by changing the set of 3 "256" values around, sorry for not making that a variable. It is basically the forward component of the view vector. FOV should be atan(forward / 128) * 2. I.e. if you set forward to 128 instead, you should get a FOV of exactly 90 degrees. Idk a...
by none
Tue Aug 02, 2022 2:59 pm
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

Here's an improved version of the above, this one takes into account that the precision is better for the b and d registers than for the x and y registers. I had a look at how the PPU actually does the math, and with this version, the result should be about the same, but point_left_x and point_left_...
by none
Tue Aug 02, 2022 9:19 am
Forum: SNESdev
Topic: Kulor's Guide to Mode 7 Perspective Planes
Replies: 62
Views: 3973

Re: Kulor's Guide to Mode 7 Perspective Planes

I've had a look into this because I tried to figure out the "mystery curve". I didn't find the issue yet though. I tried to do a perspective projection myself and I took another approach for comparison. I think this approach might be easier to understand for some people so I'd like to try ...
by none
Thu Jul 28, 2022 4:35 am
Forum: SNESdev
Topic: Games with 16x16 background tiles
Replies: 44
Views: 2009

Re: Games with 16x16 background tiles

... is there some sort of gamma mapping going on here that I'm not taking into account? Does this game have anything in common with the castle exploration/puzzle game with blocky raytraced shadows that I remember from last time? iirc, i was trying different posterization algorithms when i made that...
by none
Mon Jul 04, 2022 10:31 am
Forum: SNESdev
Topic: Games with 16x16 background tiles
Replies: 44
Views: 2009

Re: Games with 16x16 background tiles

What were you making? I was continuing work on Rem. I had been changing the games theme / style around a lot. It's already a while ago, but I've got some screenshots left over... untitled-nq8.png The water is supposed to be animated with HDMA here. I wanted a large interconnected world but the art ...
by none
Mon Jul 04, 2022 7:27 am
Forum: SNESdev
Topic: Games with 16x16 background tiles
Replies: 44
Views: 2009

Re: Games with 16x16 background tiles

even with compression level data tends to get big quite fast, but it's also depending on the level of detail you want to achieve of course.