Need to verifiy something

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Door Daemos

Paragon (1955)

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29-10-2012, 10:33

I cannot call this a bug in openmsx but just a slight difference between a real MSX and openmsx. If this is allready known or verified then just ignore everything I said.

As soon as i write the SPAT into the VDP all the sprites are hidden at the X = 0 and Y = 255 coordinates. This is in screen4 with the highest possible resolution. On openmsx everything just fine. No wierd anomalies whatever. however on the real HW using a V9958 I see those empty sprites apear in the uppermost left of the screen. I really need to put those sprites at y = 226 not to see them appear on the screen.

If this is not known can someone else try to verify this?

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Van PingPong

Prophet (3793)

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29-10-2012, 20:16

Daemos wrote:

I cannot call this a bug in openmsx but just a slight difference between a real MSX and openmsx. If this is allready known or verified then just ignore everything I said.

As soon as i write the SPAT into the VDP all the sprites are hidden at the X = 0 and Y = 255 coordinates. This is in screen4 with the highest possible resolution. On openmsx everything just fine. No wierd anomalies whatever. however on the real HW using a V9958 I see those empty sprites apear in the uppermost left of the screen. I really need to put those sprites at y = 226 not to see them appear on the screen.

If this is not known can someone else try to verify this?

the real machine is correct. remember the vdp display the sprites at y+1 coordinates. If you set y=1 the real y is 1+1=2. If you set y=255 the real coordinate is 255+1=256 that wraps up to 0 so at y=0 you see the sprite

Van Manuel

Ascended (18256)

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31-10-2012, 21:21

Daemos, can you send me the test program?

Van nanochess

Master (222)

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01-11-2012, 22:25

You can think on Y values 240-255 as -15 to 0 Y coordinate, this way you can make a sprite to enter smoothly in screen.

Van Daemos

Paragon (1955)

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02-11-2012, 16:06

Sorry for the late reply Manuel, will the rom do?

Van Manuel

Ascended (18256)

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02-11-2012, 20:58

Well, I prefer a dsk file, so that I can easily check it with my turboR and NoWind. Can you get me one?

Van Daemos

Paragon (1955)

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03-11-2012, 01:35

Thats going to be difficult. Its a big project by now and its completely built as a SCC rom. Converting this to something that loads of a floppy disk would cost me more time then the total time I needed for building this program.

I will try to isolate the sprite code and see if I can reproduce the effect when I load that piece of code as a dos program. Will that do?

Van PingPong

Prophet (3793)

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03-11-2012, 09:38

Daemos wrote:

I will try to isolate the sprite code and see if I can reproduce the effect when I load that piece of code as a dos program. Will that do?

Maybe i've misunderstood the problem, but to see this, i think it's simple: just make a VRAM dump of all tables, then send ir to manuel (BLOAD,S/BSAVE)

Van Manuel

Ascended (18256)

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03-11-2012, 10:24

Daemos: that will be very helpful. It's just about reproducing the issue in a smallest possible piece of code that would be ideal.

Van Daemos

Paragon (1955)

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03-11-2012, 13:11

good. Im on it. I will do my best to get it done fast.

Van Daemos

Paragon (1955)

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03-11-2012, 22:32

OK I have built and tested the image. Its a bin file that autoloads to keep the luxury at a maximum Wink What you see is a blue screen4 image with two damn ugly sprites somewhere in the middle, the rest off the sprites are hidden at X=0 and Y=255. On openmsx the sprites are hidden. On real msx you will notice a black square in the top left of your screen. I have no clue what happens on a V9938 since my MSX is equiped with a V9958.

I will mail you the source code as well for your convenience. The code looks somewhat ugly and the comments are sometimes a little vague but I hope it will be usefull to you.

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