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Quaternions

Started by tiutiu Jun 17, 2002 at 4:25 AM 1 reply 550+ views

Original Post

Jun 17, 2002 at 4:25 AM

I have a problem with matrices. I use quaternions to draw a sphere rotation about X-axis and following a line that rotates about Y-axis, like the railgun in quake

But now i want the sphere not to follow the line, i thought using glLoadIdentity() before DrawSphere(), but if i do that, it doesnt draws the sphere. That''s the original code:

CQuaternion qRotationY;
qRotationY.CreateFromAxisAngle(0, 1, 0, rotation);
qRotationY.CreateMatrix(matrix);
glMultMatrixf(matrix);
DrawLine();
CQuaternion qSphereRotation;
gSphereRotation.CreateFromAxisAngle(1, 0, 0, rotation * 8);
qSphereRotation.CreateMatrix(matrix);
glMultMatrixf(matrix);
DrawSphere();
rotation++

It''s a tutorial from gametutorials.com. I hope you can understand and help me :D Thank you

Fruny

203

Fruny

Jun 17, 2002 at 4:34 AM

First guess.


glPushMatrix();  
CQuaternion qRotationY;
qRotationY.CreateFromAxisAngle(0, 1, 0, rotation);
qRotationY.CreateMatrix(matrix);
glMultMatrixf(matrix);
DrawLine();
glPopMatrix();  
glPushMatrix();  
CQuaternion qSphereRotation;
gSphereRotation.CreateFromAxisAngle(1, 0, 0, rotation * 8);
qSphereRotation.CreateMatrix(matrix);
glMultMatrixf(matrix);
DrawSphere();
glPopMatrix();  
rotation++

tiutiu

Author

tiutiu

Jun 17, 2002 at 4:48 AM

It works fine, that was what i wanted

Thank you, but why if i use glLoadIdentity it DOESN''T draws anything? i think it should draw the sphere in (0,0,0). Well, thank you, now i have a better concept from matrices

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