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Hey,

During the last weeks, with a friend I worked on a demo for the SMS to be released at the VIP 2017, a french demoparty ( http://vip2017.popsyteam.org/ ).

The party was pretty cool and the demo finished first in the oldschool demo competition :D

So, here's a download link: blast!_-_the_synchrobots.zip
Youtube hardware capture: link (I finally found a cheap way to capture RGB from my SMS2 :)
And pouet.net page: http://www.pouet.net/prod.php?which=70025

What really motivated me to work on it was the release of Overdrive 2 by Titan on the Megadrive, truly inspirational work!

I may release the source code, but not sure yet about that.

Now I'll have to get some sleep :)

Awesome stuff. The rotozoomer and z axis scroller are impressive.

Congratulations on the win!

Hehe thanks!

Actually, the third person flying part is a fully featured "snes mode 7" like engine with rotations and zoom. Even if low resolution, monochrome and slightly distorded :)

gligli wrote

the third person flying part is a fully featured "snes mode 7" like engine with rotations and zoom

can you share some tech details about that? :)

You know what? I'll do better, here's the source code: https://github.com/gligli/vipdem
If you go back a few revisions (before the sequencers), you can get a rom with the pad controlling the effects!

Both the rotozoomer and the "pseudo mode 7" effects are based on what I called "MonoFB" in the code.
This is basically a way to get a 128*48 monochrome framebuffer out of the SMS VDP by having each bit of a 256 tiles tileset being a "pixel" on or off.
At first I had the resolution at 128*96 by switching tilemaps every 4 lines but this was too CPU intensive to get acceptable realtime speed.
The pseudo mode 7 works like the snes would do it, a 2D rotozoomer with the rotation and scaling changed every line.
I'm still not sure if I got the projection formula wrong or if the calculations are too low precision (8.8 fixed point) but the effect has a sort of fisheye distortion on rotations, which increases with the field of vision setting.

The textures are 2 banks of 256*64 pixels, 1 byte per pixel, so 256*128 total. Yes the format is obviously optimized for speed, and totally not for size.

As for optimisations, the best ones were self modifying code for the rotozoomer, precalculating the texture uv increments each frame and hardcoding them in the unrolled line loop in WRAM.
The other one was to use mapper slots 0 and 1 for the texture, so that I had the texture coordinates being linear 15bits with the upper bit set to 0. So, yes there is code in the textures in the demo (and you can spot it if you look for it), as you have to at least put jumps there for int vectors :)

Great work duuuude, the music is fantastic! =D

gligli wrote

[...] This is basically a way to get a 128*48 monochrome framebuffer out of the SMS VDP by having each bit of a 256 tiles tileset being a "pixel" on or off.

Oh, I understand now! Thanks! :)

Finally found a cheap way to capture RGB from my SMS2 :)
I got an old Sony DVD/HDD recorder ( https://www.sony.co.uk/electronics/support/home-video-dvd-players-recorders/rdr-... ) I bought used for 25€.
It can capture RGB directly to DVDs and quality is very good for the price I paid, and it can also be used an an HDMI upscaler.

Clever.

Does it capture full frames per second?

It captures interlaced 50Hz or 60Hz, so by using double speed bob deinterlacing on the pc, you get full framerate video.
(I used avidemux for this, and to upscale and convert from mpeg to h264 for youtube).

Wow, I find it amazing to what levels it can get to exploit SMS

Author	Message
gligli Joined: 14 Sep 2016 Posts: 81 Location: Vienne, France	Blast! - The synchrobots (new SMS demo) Posted: Sun May 14, 2017 5:56 pm Last edited by gligli on Fri May 26, 2017 1:00 am; edited 2 times in total
	Hey, During the last weeks, with a friend I worked on a demo for the SMS to be released at the VIP 2017, a french demoparty ( http://vip2017.popsyteam.org/ ). The party was pretty cool and the demo finished first in the oldschool demo competition :D So, here's a download link: blast!_-_the_synchrobots.zip Youtube hardware capture: link (I finally found a cheap way to capture RGB from my SMS2 :) And pouet.net page: http://www.pouet.net/prod.php?which=70025 What really motivated me to work on it was the release of Overdrive 2 by Titan on the Megadrive, truly inspirational work! I may release the source code, but not sure yet about that. Now I'll have to get some sleep :)

psidum Joined: 01 Jan 2014 Posts: 331	Posted: Sun May 14, 2017 10:56 pm
psidum Joined: 01 Jan 2014 Posts: 331	Awesome stuff. The rotozoomer and z axis scroller are impressive. Congratulations on the win!

gligli Joined: 14 Sep 2016 Posts: 81 Location: Vienne, France	Posted: Mon May 15, 2017 12:33 pm
	Hehe thanks! Actually, the third person flying part is a fully featured "snes mode 7" like engine with rotations and zoom. Even if low resolution, monochrome and slightly distorded :)

sverx Joined: 05 Sep 2013 Posts: 3828 Location: Stockholm, Sweden	Posted: Mon May 15, 2017 3:02 pm
	gligli wrote the third person flying part is a fully featured "snes mode 7" like engine with rotations and zoom can you share some tech details about that? :)

gligli Joined: 14 Sep 2016 Posts: 81 Location: Vienne, France	Posted: Mon May 15, 2017 4:22 pm
	You know what? I'll do better, here's the source code: https://github.com/gligli/vipdem If you go back a few revisions (before the sequencers), you can get a rom with the pad controlling the effects! Both the rotozoomer and the "pseudo mode 7" effects are based on what I called "MonoFB" in the code. This is basically a way to get a 12848 monochrome framebuffer out of the SMS VDP by having each bit of a 256 tiles tileset being a "pixel" on or off. At first I had the resolution at 12896 by switching tilemaps every 4 lines but this was too CPU intensive to get acceptable realtime speed. The pseudo mode 7 works like the snes would do it, a 2D rotozoomer with the rotation and scaling changed every line. I'm still not sure if I got the projection formula wrong or if the calculations are too low precision (8.8 fixed point) but the effect has a sort of fisheye distortion on rotations, which increases with the field of vision setting. The textures are 2 banks of 25664 pixels, 1 byte per pixel, so 256128 total. Yes the format is obviously optimized for speed, and totally not for size. As for optimisations, the best ones were self modifying code for the rotozoomer, precalculating the texture uv increments each frame and hardcoding them in the unrolled line loop in WRAM. The other one was to use mapper slots 0 and 1 for the texture, so that I had the texture coordinates being linear 15bits with the upper bit set to 0. So, yes there is code in the textures in the demo (and you can spot it if you look for it), as you have to at least put jumps there for int vectors :)

Gordman Joined: 21 Aug 2012 Posts: 363 Location: Berlin, Germany	Posted: Mon May 15, 2017 9:48 pm
	Great work duuuude, the music is fantastic! =D

sverx Joined: 05 Sep 2013 Posts: 3828 Location: Stockholm, Sweden	Posted: Tue May 16, 2017 9:12 am
	gligli wrote [...] This is basically a way to get a 128*48 monochrome framebuffer out of the SMS VDP by having each bit of a 256 tiles tileset being a "pixel" on or off. Oh, I understand now! Thanks! :)

gligli Joined: 14 Sep 2016 Posts: 81 Location: Vienne, France	Posted: Fri May 26, 2017 1:09 am
	Finally found a cheap way to capture RGB from my SMS2 :) I got an old Sony DVD/HDD recorder ( https://www.sony.co.uk/electronics/support/home-video-dvd-players-recorders/rdr-... ) I bought used for 25€. It can capture RGB directly to DVDs and quality is very good for the price I paid, and it can also be used an an HDMI upscaler.

psidum Joined: 01 Jan 2014 Posts: 331	Posted: Fri May 26, 2017 1:53 am
psidum Joined: 01 Jan 2014 Posts: 331	Clever. Does it capture full frames per second?

gligli Joined: 14 Sep 2016 Posts: 81 Location: Vienne, France	Posted: Fri May 26, 2017 9:21 am
	It captures interlaced 50Hz or 60Hz, so by using double speed bob deinterlacing on the pc, you get full framerate video. (I used avidemux for this, and to upscale and convert from mpeg to h264 for youtube).

Diskover Joined: 24 May 2017 Posts: 7 Location: Spain	Posted: Sat May 27, 2017 4:42 pm
Diskover Joined: 24 May 2017 Posts: 7 Location: Spain	Wow, I find it amazing to what levels it can get to exploit SMS

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