[squeak-dev] Re: Still pounding head against wall over glReadPixels => external buffer

Lawson English lenglish5 at cox.net
Wed Feb 10 20:33:32 UTC 2010

Andreas Raab wrote:
> Lawson English wrote:
>> I'm still having problems with my external shared memory thingie. I 
>> can evoke the unix shm* calls and obtain a reference to a shared 
>> memory buffer and attach it to squeak's heap. I can write into it and 
>> read back. I can even attach the same shared memory to two different 
>> instances of squeak and write to the buffer in one and read it with 
>> the other. What I still cannot figure out is how to take that 
>> external buffer and direct the OpenGL>>glReadPixels call to it so 
>> that I can draw using squeak and have it become a bitmap for a 
>> different application.
> Post your code. Using glReadPixels is straightforward, so there must 
> be something simple in your code that goes wrong. Simply speaking the 
> following should work fine:
> "Allocate or obtain shared memory buffer"
> xHandle := ExternalHandle allocate: rect width * rect height * 4.

Confused. ExternalHandle is...?


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