<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Jan 10, 2009, at 12:02 AM, Terje Norderhaug wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>On Jan 9, 2009, at 10:20 PM, Alexander Repenning wrote:<br><blockquote type="cite">On Jan 8, 2009, at 6:37 PM, Terje Norderhaug wrote:<br></blockquote><blockquote type="cite"><blockquote type="cite">On Jan 8, 2009, at 5:05 PM, Alexander Repenning wrote:<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">At least for the vector caveat we have a solution. The approach <br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">taken<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">may sound a bit crazy. We are implementing vector constants with a<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">combination of Lisp readers and Universally Unique Identifiers.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Perhaps not super elegant, there is bound to be a better <br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">solution, but<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">it works. Code at the end. A call to a vector function looks like<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">this<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">(glColor3fv {0.5 0.1 0.8})<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">which is pretty close to what students "know" from C. The only issue<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">is that getting the cached value is not that fast. The hash table<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">access it the bottleneck.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">What about only looking up the value at compile time? As in:<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">(glColor3fv #.{0.5 0.1 0.8})<br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I don't think the Lisp compiler could handle that because it would <br></blockquote><blockquote type="cite">try to dump a foreign pointer.<br></blockquote><br>You may get beyond that by defining a make-load-form for your <br>representation of the gl vectors.</div></blockquote><div><br></div><div>that is true. One problem is that I do not have my own class to for the foreign type. However, a foreign pointer is of the built in class macptr. A make-load-form could easily be written for that class for instance by dumping the pointer content as sequence of byes. When running the compiled code each time the a new pointer would be allocated and initialization would take place. This would be slow and a wicket memory leak. </div><div><br></div><div>When the C compiler sees an expression like</div><div><br></div><div>glColor3fv ({0.5 0.1 0.8})</div><div><br></div><div>it will put a 3 float vector constant into some static memory space, not the heap</div><div><br></div><div>This is simple is C but tricky in Lisp. The Lisp compiler does not provide a simple means to define a raw float vector constant that would end up in static space. To achieve some similar in Lisp</div><div><br></div>(glColor3fv {0.5 0.1 0.8}) will be expanded into:</div><div><br></div><div>(glColor3fv (GET-CACHED-VECTOR 78533C19-BA5D-481A-9C54-5690D0A0F25E 0.5 0.1 0.8))</div><div><br></div><div>the GET-CACHED-VECTOR uses a globally unique identifier, e.g., 78533C19-BA5D-481A-9C54-5690D0A0F25E to store and retrieve the 3 floats in a hash table. This way the foreign pointer get created and returned the first time glColor3fv is called. Every consecutive call will return the same, hash table cached value. The net result is essentially the same as in C, a vector constant.</div><div><br></div><div>Alex</div><div><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"></blockquote></blockquote></blockquote><div> </div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><blockquote type="cite"><div><br><br>-- Terje Norderhaug<br><br>_______________________________________________<br>Openmcl-devel mailing list<br><a href="mailto:Openmcl-devel@clozure.com">Openmcl-devel@clozure.com</a><br>http://clozure.com/mailman/listinfo/openmcl-devel<br><br></div></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Prof. Alexander Repenning</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><br class="khtml-block-placeholder"></p><p style="margin: 0.0px 0.0px 0.0px 0.0px">University of Colorado</p><p style="margin: 0.0px 0.0px 0.0px 0.0px">Computer Science Department</p><p style="margin: 0.0px 0.0px 0.0px 0.0px">Boulder, CO 80309-430</p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><br class="khtml-block-placeholder"></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">vCard: <a href="http://www.cs.colorado.edu/~ralex/AlexanderRepenning.vcf">http://www.cs.colorado.edu/~ralex/AlexanderRepenning.vcf</a></font></p><br class="Apple-interchange-newline"></span></span></span></div></span> </div><br></body></html>