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kmx
Member Since 06 Feb 2011Offline Last Active Aug 06 2012 09:21 PM
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In Topic: Ray/Triangle Intersection Difficulties
22 July 2012  11:31 AM
Thanks  finally figured out what was going on  my edge vectors were normalized when they should not have been.
In Topic: How to get 3D coords of window edges / glUnProject?
19 March 2011  04:11 PM
Looks like the JOGL version of gluUnProject is broken. I wrote my own version based on the C GLU source and it works.
private float[] unProject(float winX, float winY, float winZ, Matrix modelView, Matrix projection, int[] view) { float[] in = new float[4]; Matrix m = Matrix.multiply(modelView, projection).inverse(); in[0] = (winX(float)view[0])/(float)view[2]*2f1f; in[1] = (winY(float)view[1])/(float)view[3]*2f1f; in[2] = 2f*winZ1f; in[3] = 1f; float[] out = new float[3]; out[0]=m.values[0]*in[0]+m.values[4]*in[1]+m.values[8]*in[2]+m.values[12]*in[3]; out[1]=m.values[1]*in[0]+m.values[5]*in[1]+m.values[9]*in[2]+m.values[13]*in[3]; out[2]=m.values[2]*in[0]+m.values[6]*in[1]+m.values[10]*in[2]+m.values[14]*in[3]; //out[3]=m.values[3]*in[0]+m.values[7]*in[1]+m.values[11]*in[2]+m.values[15]*in[3];  don't need return out; }
In Topic: How to get 3D coords of window edges / glUnProject?
19 March 2011  03:39 PM
The the values member of the Matrix class is just an array of 16 floats. This is Java, so I don't have GLFloat. Here is the same code without using that class:
float[] p = new float[16];
float[] m = new float[16];
int[] v = new int[4];
gl.glGetFloatv(GL.GL_PROJECTION_MATRIX, p, 0);
gl.glGetFloatv(GL.GL_MODELVIEW_MATRIX, m, 0);
gl.glGetIntegerv(GL.GL_VIEWPORT, v, 0);
float[] o = new float[3];
GLU.gluUnProject(100f, 100f, 0f, m, 0, p, 0, scene.camera.viewport, 0, o, 0);
The results are the same. Like I said, gluProject, which also uses the projection and model view matrices, works great, so I don't think it is an issue with those values.
float[] p = new float[16];
float[] m = new float[16];
int[] v = new int[4];
gl.glGetFloatv(GL.GL_PROJECTION_MATRIX, p, 0);
gl.glGetFloatv(GL.GL_MODELVIEW_MATRIX, m, 0);
gl.glGetIntegerv(GL.GL_VIEWPORT, v, 0);
float[] o = new float[3];
GLU.gluUnProject(100f, 100f, 0f, m, 0, p, 0, scene.camera.viewport, 0, o, 0);
The results are the same. Like I said, gluProject, which also uses the projection and model view matrices, works great, so I don't think it is an issue with those values.
In Topic: How to get 3D coords of window edges / glUnProject?
19 March 2011  02:51 PM
Thanks, I've implemented the frustum extraction and I think I can get what I want out of it, but it looks like ti will be a lot more work.
What I don't understand is why gluUnProject is not working. If I pass 0 as the window Z coordinate, I would expect to get a point on the near clip plane. For example, in this JOGL code:
Matrix p = new Matrix();
Matrix m = new Matrix();
int[] v = new int[4];
gl.glGetFloatv(GL.GL_PROJECTION_MATRIX, p.values, 0);
gl.glGetFloatv(GL.GL_MODELVIEW_MATRIX, m.values, 0);
gl.glGetIntegerv(GL.GL_VIEWPORT, v, 0);
float[] o = new float[3];
GLU.gluUnProject(100f, 100f, 0f, m.values, 0, p.values, 0, scene.camera.viewport, 0, o, 0);
I'd expect this to give me a value close to the camera's position, instead I get wildly large values in o[0] and o[1]. It doesn't matter what I pass for win x, y.
gluProject works.
What I don't understand is why gluUnProject is not working. If I pass 0 as the window Z coordinate, I would expect to get a point on the near clip plane. For example, in this JOGL code:
Matrix p = new Matrix();
Matrix m = new Matrix();
int[] v = new int[4];
gl.glGetFloatv(GL.GL_PROJECTION_MATRIX, p.values, 0);
gl.glGetFloatv(GL.GL_MODELVIEW_MATRIX, m.values, 0);
gl.glGetIntegerv(GL.GL_VIEWPORT, v, 0);
float[] o = new float[3];
GLU.gluUnProject(100f, 100f, 0f, m.values, 0, p.values, 0, scene.camera.viewport, 0, o, 0);
I'd expect this to give me a value close to the camera's position, instead I get wildly large values in o[0] and o[1]. It doesn't matter what I pass for win x, y.
gluProject works.
In Topic: Object orientation from quaternion
07 February 2011  12:08 AM
Thanks so much, guys  I got it working!
I took the conjugate of my camera's quaternion and converted that into a matrix and then used that to rotate the object. Turns out my quaterniontoeuler function was working all along as well, so I got my angles to boot!
Thanks again.
edit: clarification: I don't use the angles for anything graphical, I use those for logic elsewhere in the game.
I took the conjugate of my camera's quaternion and converted that into a matrix and then used that to rotate the object. Turns out my quaterniontoeuler function was working all along as well, so I got my angles to boot!
Thanks again.
edit: clarification: I don't use the angles for anything graphical, I use those for logic elsewhere in the game.