Top and bottom button clicked the obj model is flipped in opengl? - opengl-es-2.0

Question

#Anton I stucked this flipping.
I downloaded the project from here.
I have four buttons each button set the title as right,left,bottom,top to the str variable.
In rendering the initial rotation axis is teapotNode_.rotationAxis = CC3VectorMake(0.1, 1, 0.3);
- (void)update:(float)dt
{
if ([str isEqualToString:#"right"])
{
teapotNode_.rotationAxis = CC3VectorMake(0.1, 1, 0.3);
angle +=2.0;
}
else if ([str isEqualToString:#"left"])
{
teapotNode_.rotationAxis = CC3VectorMake(0.1, 1, 0.3);
angle -=2.0;
}
else if ([str isEqualToString:#"bottom"])
{
teapotNode_.rotationAxis = CC3VectorMake(1,0,0);
angle +=2.0;
}
else if ([str isEqualToString:#"top"])
{
teapotNode_.rotationAxis = CC3VectorMake(1,0,0);
angle -=2.0;
}
else{
angle +=2.0;
}
teapotNode_.rotationAngle = angle;
}
I touch the top(or)down rotation button change the axis like
teapotNode_.rotationAxis = CC3VectorMake(1,0,0); object flipped.
I want the same axis position to rotate the object top to bottom and bottom to top.

Answer 1

The solution is:
You itself says the rotation axis value as (0.1,1,0.3) initial one. so don't change that value.
This project itself having separate function for rotation. that is teapotNode_.rotation
Use like this. Its working fine for me. Try this.
Globally declared:
float x=0.0;
float y=0.0;
float z=0.0;
float angle;
float rangle=2.0;
float xangle;
float yangle;
- (void)update:(float)dt
{
if ([str isEqualToString:#"right"])
{
x=0; y=1; z=0; //ROTATE OBJECT IN Y-AXIS(Y=1 & X=0)
yAngle+=rAngle; //GET ANGLE OF OBJECT ROTATION IN Y-AXIS (ANTI CLOCKWISE)
angle +=rAngle; //INCREMENT ANGLE OF OBJECT ROTATION IN ANTICLOCLWISE
}
else if ([str isEqualToString:#"left"])
{
x=0; y=1; z=0; //ROTATE OBJECT IN Y-AXIS(Y=1 & X=0)
yAngle-=rAngle; //GET ANGLE OF OBJECT ROTATION IN Y-AXIS (CLOCLWISE)
angle -= rAngle; //INC ANGLE OF OBJECT ROTATION IN CLOCKWISE
}
else if ([str isEqualToString:#"bottom"])
{
x=1; y=0; z=0; //ROTATE OBJECT IN X-AXIS(X=1 & Y=0)
xAngle+=rAngle; //GET ANGLE OF OBJECT ROTATION IN X-AXIS (ANTI CLOCKWISE)
angle += rAngle; //INC ANGLE OF OBJECT ROTATION
}
else if ([str isEqualToString:#"top"])
{
x=1; y=0; z=0 ; //ROTATE OBJECT IN Y-AXIS(X=1 & Y=0)
xAngle-=rAngle; //GET ANGLE OF OBJECT ROTATION IN X-AXIS (CLOCLWISE)
angle -= rAngle; //INC ANGLE OF OBJECT ROTATION
}
else
{
angle +=rAngle;
}
// teapotNode_.rotationAxis = CC3VectorMake(x, y, z);
// teapotNode_.rotationAngle = angle;
teapotNode_.rotation = CC3VectorMake(xAngle, yAngle, 0);
}