SpritesMind.Net

Yeah the address / register write delay seems quite short, still not short enough to use a Z80 16 bit write as LD (YMPORT), HL (16 cycles) or LD (YMPORT), DE (20 cycles) I really wanted to use it as even if high byte is written first (at addr + 1), it's not much of an issue as both address ports sha...

I finally took sometime to make some tests about the minimum safe write timings for the YM2612 / YM3438 chip. I made a lot of tests but still I couldn't test every cases and every registers but hopefully that is enough to confirm (or not) data we got from official documents. I made all my tests usin...

The flickering you're speaking about is because the high resolution mode in done in 448i/480i (note the 'i' which means "interlaced resolution"). This is because that was the way TV was working back in day. Full resolution was made in 2 frames, one frame displaying odd lines, the other frame display...

This is afaik the difference between the 2 interlaced modes on MD, one use 8x8 tiles while the other switch to 8x16 tiles.

That is just the way the register is wired, actually bit 0 is for interlaced mode while bit 1 is for interlacing type (which is meaningless in no interlaced mode).

As Enforcer said, there is 2 interlacing modes on Sega Genesis, and one of them allow to preserve correct aspect. It's just that Sonic 2 used the other mode. See VDP register 0C description here: https://segaretro.org/Sega_Mega_Drive/VDP_registers LS1-LS0: Interlace mode: 00 = no interlace; 01 = int...

Unfortunately the comparison video is completely off, i already saw it and was surprised about the title as benchmarking and compare VDP performance of the different system sound like a rather difficult task. And here what he did is basically just trying to compare the VRAM write speed from CPU for ...

SPR_loadAllFrames(..) This couldn´t be used due to severe memory restrictions; There is a 1000 tiles framebuffer in VRAM (some screens have more than 900 different tiles at once), and around 700 free tiles for 20+ sprites... If I execute this sentence: SPR_setVRAMTileIndex(entidad[aux].spr) without...

You can do that by using SPR_setVRAMTileIndex(..) so you define where the sprite tiles are located in VRAM. You have this function SPR_loadAllFrames(..) function which load all frames of a SpriteDefinition so you can easily share the tile indexes along several sprites then. The sonic sample show an ...

Welcome on the board ! As you noticed indeed forums are not as active than they were some years ago, new tools as Discord appeared and lot of people moved there. I've to admit myself that i rather prefer to use Discord (there is a SGDK discord server), it's just faster to discuss / provide support u...

Thanks ! These are very useful test ROMs !
First time i saw BlastEm failing on that much tests.
I don't even speak about Gens who fail everywhere

alko wrote: ↑

Fri Jul 15, 2022 6:57 pm

Code: Select all

 line = MEM_alloc( sizeof(Line));

No, it's really overkill and you may not release it properly later.
Just use static structure for that:

Do a complete clean of your project, you may have dirty .s files somewhere..
I also experienced it and fixed it just by cleaning some intermediate .s file not properly cleaned

Very interesting but i'm not sure to understand the VRAM/VSRAM cycles number. 85 cycles is for VRAM read operation during display ON i guess and continuous operation ? what represent the first 19 cycles ? single VRAM read operation ? I'm also very surprised by the 11 cycles obtained on long VRAM wri...

Kega isn't accurate, nor Gens is. You should test with BlastEm to see if you still have the same problem.
About the font, you can just "overwrite" it with your own tiles if you don't use it