More problems with gluunproject
BlitzMax Forums/OpenGL Module/More problems with gluunproject
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| As per your advice I downloaded and have tried to implement the NeHe article on gluunproject, but it doesn't work out quite as I had planned: I still can't convert the mouses X and Y co-ordinates into 3D opengl co-ordinates that my program can use. I don't know if this is a maths problem or due to my lack of experience with blitz. Basically, my program involves drawing a grid along the X and Y 3D axes. I want to be able to find out which square of the grid my mouse pointer is over, given that the Z co-ordinate will always be zero: Function get3dposition:tvector3(x,y) 'Converts 2d co-ordinates into 3d co-ordinates. Local viewport[4],projection:Double[16],modelview:Double[16] Local winx#,winy#,winz# Local posx:Double,posy:Double,posz:Double glgetdoublev(GL_MODELVIEW_MATRIX,modelview) glgetdoublev(GL_PROJECTION_MATRIX,projection) glgetintegerv(GL_VIEWPORT,viewport) winx=x winy=viewport[3]-y glreadpixels(winx, winy, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, Varptr winz) font.draw2d (100,100,"Win X"+winx+" Win Y"+winy+" Win Z"+winz) 'debugging gluUnProject( winx, winy, winz, modelview, projection, viewport, Varptr posx, Varptr posy, Varptr posz) Return tvector3.create(posx, posy, posz) End Function Whatever I do, winz is always 1.00000 and posx, posy and posz are nonsensical, unusable values. I have googled for information about the mechanics of the commands gluunproject and glreadpixels and I can't see how I could be using them incorrectly; perhaps I am interpreting the returned values wrong. Please help me, this is a very frustrating problem. |
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| Be carefull where you call this. Check your return as as among others: "GL_INVALID_OPERATION is generated if glReadPixels is called between a call to glBegin and the corresponding call to glEnd." |
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