[Solved]OpenGL Rotation

[3059673]

How to rotate an object (IModelCustom part in my case) around its center and specified axis ?

[TheGreyGhost]

Hi

 

I would suggest to use GL11.glRotatef(angle, rotationaxisx, rotationaxisy, rotationaxisz) immediately before you render the model.

 

This rotates by the given angle around the rotationaxis you specify.

 

Is that what you meant?

 

-TGG

 

[3059673]

When i do GL11.glRotatef(angle, axisX, axisY, axisZ) it doesn't rotate around its center . If you know EnderStorage mod's Ender tank I want to rotate a valve similar to its one . My one rotates incorrectly , around some other point, not center

[TheGreyGhost]

Hi

 

In that case, try GL11.glTranslatef(dx, dy, dz) before and (-dx, -dy, -dz) after the glRotatef.  dx, dy, dz is how much you need to move your centre of rotation by.  This will change the centre point of rotation - i.e. you need to translate your model to the origin, rotate around the origin, then translate it back again.  I have to admit I'm not 100% sure about the correct translation to do after the Rotatef.  I think -dx,-dy,-dz is right, but you might need to play around to make sure.

 

-TGG

[Draco18s]

The problem is that "center" isn't a property of a model.  It's an idea.

[rich1051414]

First of all, the model must be centered on the relative point 0,0,0. By that I mean, in your model rendering, the offset point x=0, y=0, z=0 is the center-most point in your model. Then any rotations will rotate at the center point in the model.

[3059673]

Hi

 

In that case, try GL11.glTranslatef(dx, dy, dz) before and (-dx, -dy, -dz) after the glRotatef.  dx, dy, dz is how much you need to move your centre of rotation by.  This will change the centre point of rotation - i.e. you need to translate your model to the origin, rotate around the origin, then translate it back again.  I have to admit I'm not 100% sure about the correct translation to do after the Rotatef.  I think -dx,-dy,-dz is right, but you might need to play around to make sure.

 

-TGG

 

Thanks that solved the problem; -dx,-dy,-dz is ok