KimikoMuffin's picture

GraphicsMode.Default.Depth is 32bpp on a laptop which only supports up to 24bpp depth.

Project:The Open Toolkit library
Category:bug report

I've been trying out both 1.0.0 and the nightly builds, and I've run into a crashing bug on the latest nightly build (20120315) on an older machine: GL.BlendEquation throws an EntryPointNotFoundException with the message "Unable to find an entry point 'glBlendEquation' in DLL 'OpenGL32.dll'." However, it works just fine when I use version 1.0.0 of OpenTK instead. It's a Windows XP laptop with 1 GB of RAM and a Radeon Xpress 200M graphics card; I'm not getting problems on a more modern Windows 7 machine.


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the Fiddler's picture


GL.BlendEquation requires OpenGL 1.2 or higher. Use GL.GetString(StringName.Version) to check that OpenGL 1.2 is supported. (Your Xpress 200M should be alright, provided OpenGL drivers are installed).

KimikoMuffin's picture


GL.GetString(StringName.Version) returned "1.1.0", so I guess that was it! Wonder why it was working on OpenTK 1.0, then ... Ah well, if you'll excuse me, I'm going to go bang my head against the wall trying to find drivers that will work on a laptop which is only slightly newer than Windows XP SP2.

the Fiddler's picture


Hm, the GraphicsMode selection code is a little rough around the edges in the nightly builds, and it might be returning a mode without hardware acceleration. Try using GraphicsMode.Default or another mode like 32/16bpp color with 32/24/16bpp depth.

(In theory, non-accelerated modes should not be returned, unless the system doesn't support hardware acceleration at all).

KimikoMuffin's picture


Well, it was running GraphicsMode.Default to begin with, so let's have a look-see ...

Hmm. It crashed when I manually set it to 32bpp color and 32bpp depth, but it did work properly with 32bpp color/24bpp depth.

KimikoMuffin's picture


Title:Crashing bug in GL.BlendEquation on older laptop» GraphicsMode.Default.Depth is 32bpp on a laptop which only supports up to 24bpp depth.

Notwithstanding the fact that the laptop still only had OpenGL 1.1.0 and therefore technically isn't supported, I'm gonna rename the issue to something that actually reflects what the problem was.

the Fiddler's picture


Version:1.x-dev» 1.1.0-rc1
Status:open» closed

This has been fixed in 1.1-rc1.