View Full Version : Animations

05-10-2004, 04:33 AM
I'm having problems with implementing animations that are controlled by equations.

Im currently doing simple rotations. When rotating in x it seems to work fine but when rotating in y or z it turns a but and then just stops. Ive checked the values being returned from my maths and they all increase as they should, so i cant figure out why its doing this.

Can anyone help??

05-10-2004, 05:40 AM
can you display some code? it would help a lot.


05-10-2004, 06:12 AM
well this is the code i use to work out the rotations for the x y z angles

object.animRotate.x=object.rotation.x+(animations. axis.x*(animTime*animations.speed));
object.animRotate.y=object.rotation.y+(animations. axis.y*(animTime*animations.speed));
object.animRotate.z=object.rotation.z+(animations. axis.z*(animTime*animations.speed));
}its pretty much initial rotation +speed*time. The mutltiplication before speed*time is the axis that the rotation is being performed on.

05-10-2004, 02:17 PM
Put glPushMatrix() - glPopMatrix() around your glRotate() maybe ?

05-11-2004, 12:02 PM
yeah i have glpush and glpop. heres my drawing code:

void Recursive_Draw(TreeStorageNode object)
int i;
TreeStorageNode animatedObject;


for(i=0; i<animationData->controllerCount;i++){
if(strcmp(animationData->controllers[i].controlledObject, object.objectName)==0){
animatedObject=Update_Animation(object, animationData->controllers[i], newSimTime);

printf("ROTX %.2f ROTY %.2f ROTZ %.2f\n\n", animatedObject.animRotate.x, animatedObject.animRotate.y, animatedObject.animRotate.z);
glRotatef(animatedObject.animRotate.x, animatedObject.animRotate.y, animatedObject.animRotate.z, object.rotation.w);


glTranslatef(animPosition.x, animPosition.y, animPosition.z);

glVertexPointer(3, GL_FLOAT, sizeof(VectorStorage), &amp;object.mesh[0].pos);
glNormalPointer(GL_FLOAT, sizeof(VectorStorage), &amp;object.mesh[0].normal);
glTexCoordPointer(2, GL_FLOAT, sizeof(VectorStorage), &amp;object.mesh[0].texCoord);
glDrawElements(GL_TRIANGLES, 3*object.mesh->triangleCount, GL_UNSIGNED_INT, object.mesh->indices);

for(i=0; i<object.childCount; i++)

} its not great but it reflects my rather rubbish programming techniques

05-11-2004, 01:46 PM
>> glRotatef(animatedObject.animRotate.x, animatedObject.animRotate.y, animatedObject.animRotate.z, object.rotation.w);

Hehe, :p don't forget to read the docs ;)
glRotate is defined as :
glRotatef (GLfloat angle, GLfloat x, GLfloat y, GLfloat z);

So you need to use :

glRotatef( rotate.z , 0,0,1);
glRotatef( rotate.x , 1,0,0);
glRotatef( rotate.y , 0,1,0);The correct order will depend of your case.

05-12-2004, 01:21 AM
ohh im so dumb. thanks very much, most problems i come across are ones like these it gets a bit tiresome hehehe.

ps it works like a dream

05-12-2004, 09:35 AM
ok so i have the animations working just perfectly but now things are rotating around the axis of other objects axis. I was thinking it was my pop push matrices being in the wrong place but ive looked over it and i cant see that its wrong.

can someone with a fresh pair of eyes see if this is the problem. the code from above hasnt changed much from what i currently have. so if there is a problem it will be in there.

cheers for any help