#385 opengl output falls back to surface output in truecolor modes

[Bertram Felgenhauer]

Symptom: setting windowresolution in dosbox.conf has no effect when running programs in truecolor mode. instead, the window is resized to the program's native resolution.

Analysis: In src/gui/render.cpp, the GFX_RGBONLY flag is set in the gfx flags for truecolor modes. In src/gui/sdlmain.cpp, both GFX_GetBestMode and GFX_SetupSurfaceScaled check that flag for the 'opengl' output, and refuse to use it when the flag is set. Removing these two checks makes the problem disappear. (They appear to be a copy of checks for the 'overlay' output, which I believe works in YUV colorspace.)

Additional information: I'm using dosbox in windowed mode under Linux

[Bertram Felgenhauer]

Oops, I meant to change the milestone. Dosbox version is 0.74.

[Brandon J. Van Every]

I'm also using Dosbox 0.74 on Linux and see this behavior as well. Changing windowresolution has no effect. The result is an annoyingly small window on my 1440x900 screen.

[Maks Verver]

This affects fullscreen mode too, not just windowed mode, and like Brandon says, this is very annoying on Linux because it means there is not a single output that supports scaling in RGB modes.

Attached is a simple patch following Bertram's suggestion, which does seem to fix the problem.

[Le Gluon du Net]

Hello,

does this bug is still present in the last source or corrected?

[Bertram Felgenhauer]

Yes, this behavior persists. The patch still seems to work as well.

[Le Gluon du Net]

but this patch is for opengl only, not overlay? it works for all dosbox platform?

[Bertram Felgenhauer]

Yes, the patch is for opengl only; the (SDL) overlay works in YUV color space, so I believe falling back to the plain surface when RGB data is provided is necessary there.

I cannot conveniently test this on anything but Linux. SDL and OpenGL both aim to be platform independent though so I expect this to work whenever OpenGL is available.