October 2009 - cl-opengl-devel - mailman3.common-lisp.net

[cl-opengl-devel] sdl:set-gl-attribute
by Luke J Crook 08 Oct '09

08 Oct '09

Pardon the question concerning lispbuilder-sdl in this list, but I have a feeling more developers here use lispbuilder-sdl and cl-openl in combination and I may have a better chance of having this question answered. The set-gl-attribute command in lispbuilder-sdl breaks when using SBCL in Windows 7 or OS X. This command is most often used to set doublebuffer mode; as shown below; (sdl:set-gl-attribute :SDL-GL-DOUBLEBUFFER 1) Is there a way to set the OpenGL attributes using cl-opengl, and if there is, does this work on Windows 7 and OS X? I'm trying to determine if this is a lispbuilder-sdl problem, a SDL problem, or a CFFI problem In SBCL: * (sdl:with-init () (sdl:set-gl-attribute :sdl-gl-doublebuffer 1)) debugger invoked on a SIMPLE-ERROR: EXCEPTION_ACCESS_VIOLATION Type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL. restarts (invokable by number or by possibly-abbreviated name): 0: [ABORT] Exit debugger, returning to top level. ("bogus stack frame") And in OS X; CORRUPTION WARNING in SBCL pid 69894(tid 2693764352): Memory fault at 17c (pc=0x8654d, sp=0x11ffa80) The integrity of this image is possibly compromised. Continuing with fingers crossed. debugger invoked on a SB-SYS:MEMORY-FAULT-ERROR in thread #<THREAD "initial thread" RUNNING {119BEB99}>: Unhandled memory fault at #x17C. Thanks, - Luke

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[cl-opengl-devel] Some issues porting an example from nehe.gamedev.net
by Malcolm Reynolds 05 Oct '09

05 Oct '09

Hello, I'll start by saying I'm fairly new to Common Lisp and almost entirely new to doing any practical graphics programming, and I could well have missed something hugely obvious here.. but I hope not. I'm going to need to write some graphics code in the phd program I've just started. Someone pointed me at nehe.gamedev.net's opengl tutorials and after slogging through up to number 5 - http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=05 - reading through people's objective C, I decided to try and port it to Lisp using cl-opengl. I looked at a couple of examples (cube.lisp and gears.lisp) to get the boilerplate about window generation, and from there it was pretty much just a case of porting the drawRect method from the Objective C version to the glut:display method for my code. I have clearly missed something though, as the visibility for my geometry is all off - for example the base of the triangle is drawn in front of anything else and most faces of the cube do something a bit whacky. I know that which order points are drawn in is crucial because that defines the 'front' of a triangle/quad, but I'm pretty sure I have copied the points in the same order as my Objective C version (which works fine, see screenshots) Working version (objective C): http://img260.imageshack.us/i/picture3g.png/ Non working version: http://img209.imageshack.us/i/picture4k.png/ In case it's not clear, in the non-working version above the corner you see in the pyramid is actually the back corner. It shouldn't be visible. When the pyramid rotates so that you should be looking down on the point at it, you see only the base instead of only the four top faces. I have similar issues with the cube faces, some of them only being visible from the 'inside'. >From what I can tell from M-.'ing through the source, cl-opengl passes directly through to the corresponding C functions, so I'm pretty confident the 'which order to specify points' hasn't changed. This means presumably something in my setup is off, something to do with the depth buffer maybe? I guess the issue might be in the keyword args in function calls in #'glut:display-window method but it's hard to figure out exactly what the arguments to these functions will be except a guess at translating them into lisp-ish hyphenated lowercase. Here's the entire source to my lisp program: http://paste.lisp.org/display/88230 and the relevant file from my Obj-C version (I basically tried to copy everything from the drawRect and reshape methods): http://paste.lisp.org/display/88231 If anyone can point me in the right direction that would be most appreciated.. I'm looking forward to using Lisp for some serious work once I get these niggles sorted out. Cheers, Malcolm

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[cl-opengl-devel] uniformf problem (and patch)
by Billy 02 Oct '09

02 Oct '09

Hi, I was running into some problems setting a uniform variable with UNIFORMF - I could give it a number, but for some reason it wasn't evaluating anything else passed to it, reporting "The value X is not of type REAL." Anyway with some discussion on #lisp, stassats came up with a little patch that seems to work. Here's my original effort that had problems: http://paste.lisp.org/display/88062 And the patch: diff -rN -u old-cl-opengl/gl/opengl.lisp new-cl-opengl/gl/opengl.lisp --- old-cl-opengl/gl/opengl.lisp 2009-10-02 08:37:02.397150466 +0400 +++ new-cl-opengl/gl/opengl.lisp 2009-10-02 08:37:02.454149983 +0400 @@ -633,11 +633,15 @@ (define-compiler-macro uniformf (&whole form location x &optional y z w) (declare (ignore form)) - (cond - (w `(%gl:uniform-4f ,location ,(float x) ,(float y) ,(float z) ,(float w))) - (z `(%gl:uniform-3f ,location ,(float x) ,(float y) ,(float z))) - (y `(%gl:uniform-2f ,location ,(float x) ,(float y))) - (x `(%gl:uniform-1f ,location ,(float x))))) + (flet ((float* (x) + (if (numberp x) + (float x) + `(float ,x)))) + (cond + (w `(%gl:uniform-4f ,location ,(float* x) ,(float* y) ,(float* z) ,(float* w))) + (z `(%gl:uniform-3f ,location ,(float* x) ,(float* y) ,(float* z))) + (y `(%gl:uniform-2f ,location ,(float* x) ,(float* y))) + (x `(%gl:uniform-1f ,location ,(float* x)))))) (defun uniform-matrix (location dim matrices &optional (transpose t)) (check-type dim (integer 2 4))

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[cl-opengl-devel] Incorrect re-initialization of cl-glut on image loading
by Kalyanov Dmitry 02 Oct '09

02 Oct '09

If I load cl-opengl, save the Lisp image (e.g., with sb-ext:save-lisp-and-die on SBCL) and then load the image and call (cl-glut:init), then cl-glut:: %glutInit doesn't get called because the variable cl-glut::*glut-initialized- p* is set to T (it retains its value when the image is saved). For me, this manifests in the following error: >freeglut ERROR: Function <glutSolidTeapot> called without first calling 'glutInit'. If I set cl-glut::*glut-initialized-p* to NIL before saving the image, then cl-glut works after restarting the saved image. I propose to clear the cl-glut::*glut-initialized-p* when the image is saved. The source code change (for SBCL) might look like this: (defun clear-initialized-p () (setf *glut-initialized-p* nil)) #+sbcl (pushnew 'clear-initialized-p sb-ext:*save-hooks*)

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