[Non urgent, only a cosmetic bug] Pixel blocks of top of a resized preview are weirdly or badly filled.

zebulon-1st commented 5 years ago

Summary

The pixel blocks, at top of the preview, are not completely (or badly) filled. This happens only in a resized preview, and only in the preview. The output image file (eg PNG) is good. This happens always to the pixel blocks at top of the preview, with any Render_Pattern. This is only visible if you don't use radiosity, because radiosity already fills its own pixel blocks before. I haven't tried with mosaic preview. I haven't tried with Output Alpha (+ua).

(Note: This cosmetic problem already exists in previous 3.7RC7 linux source.)

Environment

Source code Git tag: branch 3.7-stable
POV-Ray version: POV-Ray 3.7.0.8.unofficial (from povray --V)
Operating system: Debian 9 Stretch (stable)
Hardware platform: x86-64
Compiler: gnu g++ 6.3.0
libsdl: 1.2.15 (from configure.log)

Linux Build

Note : Since it works in Debian, I have uncommented the SDL_WM_SetCaption() line, in povray/unix/disp_sdl.cpp, before building povray :

...
void UnixSDLDisplay::SetCaption(bool paused)
{
    ...
    // FIXME: SDL_WM_SetCaption() causes locks on some distros, see http://bugs.povray.org/23
    SDL_WM_SetCaption(f.str().c_str(), PACKAGE_NAME); /* works in Debian */
    ...
}
...

Steps to Reproduce

Output with preview display ON, with a size big enough to force the resize of the preview : ... +d -w1024 -h1024 -bs4 ...

Expected Behavior

Pixel blocks filled correctly, as with smaller and non resized preview :

Note : As I said at top of this issue, the output PNG file is ok :

Actual Behavior

The first pixel blocks are not filled correctly with resized previews. This always happens on top of the window, with any Render_Pattern value :

wfpokorny commented 5 years ago

I've not been able to re-produce the v3.7 / sdl1.2 mangled results above in a limited effort. Ubuntu 18.04. Also sdl1.2.15 but gcc 7.4.0.

I've been running Jerome's sdl2 patch to the 3.8 master branch for some months - which also includes the title text. For a stand alone branch of this change see: https://github.com/wfpokorny/povray/tree/update/JG_sdl2

I've seen no issues for windows not sized down to fit the screen. Where windows have been sized down to fit the screen I often see a single line in the very upper left (first block rendered?) which look to be somewhat scrambled. Occasionally see a few other similar lines of scrambled pixels. I've not seen results as scrambled as those posted above for the sdl1.2 v3.7 implementation with the newer code.

I'd suppose any fix for scrambling issues would include a move to sdl2 and be done based upon v3.8 or later. So, in short, I've not myself reproduced the original issue with v3.7, but there to me looks to be something minor amiss with a newer v38 / sdl2.0.8 implementation when the window is sized down to fit the screen.

c-lipka commented 3 years ago

For the records: Given that this issue is flagged as non-urgent and cosmetic, I'm quite confident that we don't want to put this on our plate as we're preparing for v3.8.0 release.

POV-Ray / povray