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Because I sometimes do not need to write the upper byte

But I wrote a macro doing both write

(I'm never sure when a function is inlined, so I guess macros are faster)

OK, I think I understood the problem.

I looked in source code of DMA_doVRamFill. In fact, the "value" parameter needs to be u8.

Then, when sending the value to data port, you write :

*pw = value | (value << 8);

because the 1st word write sends the lower byte to adress, the upper byte to ...

I have a problem with DMA_doVRamFill. My plane A starts at VRAM adress 0xC000 with :

0xC000 : 2108 2108 2108 2108 2108 2108 2108 2108 2108 2108

(2108 means : tile 0x108 with palette 1, no priority, no flips) (If I'm not mistaken, VRAM is little-endian so it should be 08 21 inside).

I want to ...

(image attachment doesn't seem to work : it's the second boss of Shinobi arcade )

Thank you, it seems to work like a charm

Get ready Black Turtle !

Thanks

But don't I need to disable HInt at the end of my_callback() ?

If I don't do it, won't HInt be triggered at every line after scanline ?

Thanks, you confirm what I thought :)

So, is this the way to do it :

1) just after VBlank, I set register 10 with the (scanline - 1) and enable HInt (with a custom callback function) :

VDP_setReg(10, scanline - 1);
SYS_setHIntCallback(my_callback)
SYS_setInterruptMaskLevel(4);

2) the callback ...

I also was wondering something : I want to simulate parallax scrolling in one plane : lines above line 448 of the map must scroll at half-speed, lines below at full speed.

There can be vertical scroll, so line 448 of the map is not always at the same screen height (let's call scanline the ...

Hello,

I want to use Horizontal scrolling per tile mode, and I see I shuld use :

VDP_setHorizontalScrollTile(VDPPlane plane, u16 tile, s16* values, u16 len, TransferMethod tm);

I read that TransferMethod tm can be :

* Transfer method.<br>
* Accepted values are:<br>
* - CPU<br>
* - DMA<br ...

I think I never talked about my project here, which is a shame since this forum got me the most valuable advices about Megadrive programming.

I've started some years ago a port of the 1987 Shinobi arcade game on Megadrive. Back in the days I was in love with this game, and I thought it was really ...

Yes we did, and you're right, that's indeed the problem. At first I thought I had a priority problem, then that isPlayingPCM was releasing info too early, but it's the contrary : it takes too much time to consider the channel used.

I'll update my "pcm manager" to block a channel during the 2 first ...

After some texts, I think the problem is related to XGM_isPCMPlaying...

I noticed sometimes, PCM sfx doesn't start when I call XGM_playPCM. Especially when I play very close sfx.

Therefore I have the 3 questions :

1) is the priority the only thing that can prevent a PCM to be played ?

2) does a priority of 15 mean that the PCM will overpass any playing PCM (so it can ...

Huge move. Thank you all for gathering this...

Mmmh, I'll try to compile in my fridge and keep you informed