GLSprite::Draw crash

[dpJudas]

While playing a little bit on my computer gzdoom suddenly crashed in the following line: https://github.com/coelckers/gzdoom/blo ... e.cpp#L378

It would appear that actor can be null because it died in what looks like a null pointer access error:

Crash Address: 0x00007ff6d6d99432 {gzdoom.exe!GLSprite::Draw(int pass), Line 378}
Crash Code: 3221225477
CrashSummary:
Code: C0000005 (Access Violation - tried to read address 00000000000000EC)
Address: 00007FF6D6D99432

[dpJudas]

Oh and during shutdown trying to tell me about this error it died with this call stack:

> gzdoom.exe!FVertexBuffer::~FVertexBuffer() Line 70 C++
gzdoom.exe!FFlatVertexBuffer::`scalar deleting destructor'(unsigned int) C++
gzdoom.exe!FGLRenderer::~FGLRenderer() Line 179 C++
gzdoom.exe!OpenGLFrameBuffer::~OpenGLFrameBuffer() Line 126 C++
gzdoom.exe!OpenGLFrameBuffer::`scalar deleting destructor'(unsigned int) C++
gzdoom.exe!I_ShutdownGraphics() Line 113 C++
gzdoom.exe!ExitFatally(unsigned __int64 dummy) Line 1153 C++

Edit: This isn't the full call stack. It died deep inside the Nvidia driver executing glDeleteBuffer. So the shutdown crash might not be gzdoom's fault, but figured I'd mention it anyway in case it is seen again in the future.