<div dir="ltr">Cool<div><br></div><div style>I have wished for something like this a long time</div><div style><br></div><div style>Karl</div><div style><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On Fri, Mar 15, 2013 at 7:27 PM, tim Rowledge <span dir="ltr"><<a href="mailto:tim@rowledge.org" target="_blank">tim@rowledge.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
One of the issues with doing Squeak/Scratch for the Pi is the rather dismal bitblt performance. I'm working on that with another colleague in the UK, but one interesting common case I've found in my tracing runs of Scratch is alot of use of pixelValueAt:, which builds a bitblt and runs it to move a single pixel and then look at it. That adds up to a lot of work for not much result so I've written a little plugin with (so far) a single prim to read a single pixel with rather less fiddling.<br>
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So far it only deals with Squeak internal format bitmps (ie demented spawn of satan big-endian not-at-all-like-RISC-OS structure) but does cope with 1/2/4/8/16/32 bpp ok. I could probably make it handle LSB (which is closer to convenient for almost all machines these days) and probably even external bitmaps if there is any real need.<br>
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Currently the code is all on its lonesome but I suppose it could be added to the bitblt plugin if that's a popular idea.<br>
Included is a copy for anyone interested to try out and find bugs -<br>
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tim<br>
--<br>
tim Rowledge; <a href="mailto:tim@rowledge.org">tim@rowledge.org</a>; <a href="http://www.rowledge.org/tim" target="_blank">http://www.rowledge.org/tim</a><br>
Strange OpCodes: IA: Illogical And<br>
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