TOLTECS: Sprite residues left behind on ego walking

[raziel-]

ScummVM 2.2.0git (Nov 14 2019 18:14:53)
Features compiled in: Vorbis FLAC MP3 RGB zLib MPEG2 Theora AAC A/52 FreeType2 JPEG PNG cloud (servers, local)

Ego sprites leaves residues of himself on the screen while walking.
Scrolling and moving the sprite over them will make them go away.

This happens in all game scenes, but most prominent on the first scene. Every part of ego's sprite can be affected (hat, shirt, trousers, shadow), but mostly th shirt (white pixels) can be seen.

Steps to reproduce:
In the very first scene after the intro:
1) Click on the rock on the bottom of the screen (down left)
2) After ego has positioned himself behind the rock, click on the right edge just underneath the bushes in the middle of the screen (just not directly ON the bushes, so no GO TO BUSHES comes up, that works too, but it will probably start scrolling and remove the mush)

See screenshot.

3 Skulls of the Toltecs (DOS/English)

AmigaOS4 - SDL - PPC - BE
gcc (adtools build 8.3.0) 8.3.0

[raziel-]

white pixel mush can be seen in the middle of the screen

[raziel-]

I think this is because of the "scrolling" of the screen when moving around.
There is no residues when there is no scrolling

[dwatteau]

I thought I had tracked this somewhere, but I can reproduce this issue on other platforms with slower rendering, such as some underpowered netbook with a slow framebuffer-based renderer (either with SDL1.2 or SDL2) and on the PS3 port.

So I wonder if this can't come from the graphics code not properly cleaning things up when the device isn't able to render things fast enough.

[raziel-]

Means it's back to being a platform gfx driver specific thing?

[dwatteau]

Replying to raziel-:

Means it's back to being a platform gfx driver specific thing?

I don't think so; I'd say it's something in the way the engine deals with graphics code which is suboptimal in some way, and that shows up on older, more limited devices. But that's not my area and so it's just a very wild guess :)

I'll run Gprof on that old netbook to see if I can make something out of this.

[raziel-]

and that shows up on older, more limited devices

Why do you need to stress that?
I like to think I'm on a perfectly fine (and capable) platform *sob*

😀

Thank you for taking a look