On 05/24/2012 05:00 AM, tommyl...@eircom.net wrote: > > Hi Kevin. > I think you should concider using Glu.LookAt function, which should solve all > your problems. > > I used it in collision project (attached) to follow the ball. > You just set the camera with few parameters, and that's it! Please check the > command help in Gambas. > Simply speaking, you define eye point's (x,y,z position - no need for scale > or translate), point you look at and point where the top of camera is (by > changing it, you rotate the world in front of you), so I think that would > solve it. See the attached example to see how I did it. Press F3 to see how > it works. > > > From glu man pages: > > NAME > gluLookAt - define a viewing transformation > > > C SPECIFICATION > void gluLookAt( GLdouble eyeX, > GLdouble eyeY, > GLdouble eyeZ, > GLdouble centerX, > GLdouble centerY, > GLdouble centerZ, > GLdouble upX, > GLdouble upY, > GLdouble upZ ) > > > PARAMETERS > eyeX, eyeY, eyeZ > Specifies the position of the eye point. > > centerX, centerY, centerZ > Specifies the position of the reference > point. > > upX, upY, upZ Specifies the direction of the up vector. > > DESCRIPTION > gluLookAt creates a viewing matrix derived from an eye > point, a reference point indicating the center of the scene, > and an UP vector. > > The matrix maps the reference point to the negative z axis > and the eye point to the origin. When a typical projection > matrix is used, the center of the scene therefore maps to > the center of the viewport. Similarly, the direction > described by the UP vector projected onto the viewing plane > is mapped to the positive y axis so that it points upward in > the viewport. The UP vector must not be parallel to the > line of sight from the eye point to the reference point. > > Let > > ( centerX - eyeX ) > F = | | > | centerY - eyeY | > ( centerZ - eyeZ ) > > Let UP be the vector (upX,upY,upZ). > > Then normalize as follows: f = _____ > ||F|| > > UP' = ______ > ||UP|| > > Finally, let s = f x UP', and u = s x f. > > M is then constructed as follows: > ( s[0] s[1] s[2] 0 ) > | u[0] u[1] u[2] 0 | > M = | | > |-f[0] -f[1] -f[2] 0 | > | 0 0 0 1 | > ( ) > and gluLookAt is equivalent to glMultMatrixf(M); > glTranslated (-eyex, -eyey, -eyez); > > I hope I did help. > > Tomek. >
Cool little program. I posted here as well about the issue: http://www.opengl.org/discussion_boards/showthread.php/177719-Matrix-scale-rotation-and-translation-with-repsect-to-2D-camera and someone had the same idea about using GluLookAt(). I'm still stuck on the camera rotation though. I need it to spin perpendicular to the direction it's pointing, like tilting your head to the side but 360 degrees. I think I understand that I need to apply the camera's orientation to the "up vector", but don't really know how to go about it. I don't think it's a matter of just plugging the orientation into one of the three vector values. Any insight into how exactly the up vector works in this regard? -- Kevin Fishburne Eight Virtues www: http://sales.eightvirtues.com e-mail: sa...@eightvirtues.com phone: (770) 853-6271 ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
