Search found 400 matches

by Miquel
Wed Apr 17, 2019 11:59 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 27
Views: 1870

Re: Help scale and rotation sega genesis

What about moving to H32 lines before enabling display?, something like this: 1. Horizontal exception on line 192, disable display, switch to H40 mode 2. DMA bitmap from buffer to VDP 3. Begin rendering bitmap to buffer… 4. Horizontal exception on line 30, switch to H32 mode 5. Horizontal exception ...
by Miquel
Wed Apr 17, 2019 8:28 pm
Forum: Blabla
Topic: Where is your very first Megadrive/Genesis now?
Replies: 2
Views: 126

Re: Where is your very first Megadrive/Genesis now?

Around the launch of Sonic 3 in Europe I bought my first MegaDrive, in fact I changed a used GameGear with several games for a new MegaDrive with Sonic 1, 2 & 3. Muuuuuch later I overclocked the cpu to 2x the stock speed, and a few months later the 68K said that’s enough and stop working. Since then...
by Miquel
Wed Apr 17, 2019 8:10 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 27
Views: 1870

Re: Help scale and rotation sega genesis

I agree with what you say. My point is if you switch modes, H40 on extended vertical exception and H32 on reduced display time, you get the best of both worlds, that is more cpu time since DMA goes faster for the same amount of data. Something like this: 1. Horizontal exception on line 192, disable ...
by Miquel
Wed Apr 17, 2019 6:08 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 27
Views: 1870

Re: Help scale and rotation sega genesis

[...] Done. You have mode7 an probably not much more cpu time to waste. I forgot to say that both gasega68k and Stef change the resolution from 320 to 256 in horizontal. The thing is H32 mode runs at slower clock, that means less throughput, so my supposition is they only go to that mode on display...
by Miquel
Fri Apr 12, 2019 7:48 pm
Forum: Super 32X
Topic: Using 32x as a 3rd plane, possible?
Replies: 3
Views: 156

Re: Using 32x as a 3rd plane, possible?

32X output can only be above or below MD layer, it cannot do intermediates. Only way you could do some shadowing etc. is to render the output of MD itself on 32X side and apply whatever you want. I was thinking something like "Crusader of Centy"/"Solei" when the clouds obscure the scenario but are ...
by Miquel
Fri Apr 12, 2019 4:40 pm
Forum: Super 32X
Topic: Using 32x as a 3rd plane, possible?
Replies: 3
Views: 156

Using 32x as a 3rd plane, possible?

1) What I want to do is: - MD/Genesis works as you expect, as it is alone (no exception table differences, for example) - if MD detects 32x: -----> 32x is initialized, a program is uploaded along some graphics -----> All 32x does it wait for a word (command) to display this or those other screen - M...
by Miquel
Tue Apr 09, 2019 2:57 pm
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 800

Re: Compiling an emulator for enhanced Megadrive

The focus should be on making game development easy, and this means that when somebody makes a game doesn’t want to do two games instead because there are two sets of rules. So, having RGB444 is much more desirable than anything else because is 100% compatible with the default RGB333. And why you ne...
by Miquel
Sun Apr 07, 2019 7:26 pm
Forum: SGDK
Topic: Timer interrupts
Replies: 10
Views: 270

Re: Timer interrupts

I didnt mean for my message to come across in any way that might offend people. You haven't offend anyone. :) I was merely expressing my frustration with the hardware. As much as i love the sega megadrive, timer interrupts could've greatly improved the amount of logic and code to achieve certain ti...
by Miquel
Wed Apr 03, 2019 3:25 pm
Forum: SGDK
Topic: Timer interrupts
Replies: 10
Views: 270

Re: Timer interrupts

Possibly, if you are thinking on a game, the hidden discussion we are having here is how to structure the engine, in particular, how to make easy developing the IA. A bit of addendum: This cool way of managing concealed ideas remains me on how calm you have to be while endorsing diplomacy whit other...
by Miquel
Wed Apr 03, 2019 11:56 am
Forum: SGDK
Topic: Timer interrupts
Replies: 10
Views: 270

Re: Timer interrupts

Since you update the game on a frame basis doesn't make sense to have more accurate timing than that.
The exceptions could be sound/music and sintetic tests.
by Miquel
Mon Apr 01, 2019 4:31 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 27
Views: 1870

Re: Help scale and rotation sega genesis

Hi, this is a little demo that I recently put together that handles scaling and rotation. There is a lot of precalculation in the ROM, however, any bitmap can be scaled without requiring each image to be pre-scaled and rotated. https://m.youtube.com/watch?v=8yS6xhLGJGk Is it all precalculated or is...
by Miquel
Mon Apr 01, 2019 3:34 pm
Forum: Exodus
Topic: Active Disassembly
Replies: 8
Views: 749

Re: Active Disassembly

That’s right, better some intelligent disassembly than a raw one, even if there are mistakes. An that’s why point to point disassembly helps a lot, since you can change it while you are reading. Still on an automatic dissasembly there are occasions where is not possible to know if a piece of data is...
by Miquel
Sun Mar 31, 2019 5:27 pm
Forum: Exodus
Topic: Active Disassembly
Replies: 8
Views: 749

Re: Active Disassembly

No, I haven’t.
- How it works ? Perhaps it just marks the rom as code or data as it emulates ?
- Can be integrated into an asm file easily ?
by Miquel
Sat Mar 30, 2019 11:49 am
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 27
Views: 1870

Re: Help scale and rotation sega genesis

danibus wrote:
Sat Mar 30, 2019 9:35 am
When gasega68k said 64KB external ram.... Which Ram? In cartridge?
He uses the save ram on the cartridge (64 KB, words) to store the virtual map. Most emus give you that by default.
by Miquel
Sat Mar 30, 2019 8:52 am
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 27
Views: 1870

Re: Help scale and rotation sega genesis

Ok, gasega68k just explained it on his first post, really silly of me to not read it :(. So that’s how a mode7 can be accomplished: - Use HINTs to crop the screen a little. -> You have around 7KB of bandwidth on vertical display retrace 60hz, but with the decrease screen size you obtain more. Don’t ...