Phoresis

03-08-2007, 08:48 AM

Currently I have code that is repeatedly called which animates a 2d polygon rotating around a point, based on how close to the point it is.

the problem is, my code seems to work fine for a radius of 100 or greater, but the polygon doesn't rotate for a radius shorter than that.

Here is my code:

if (items[0] != NULL)

{

//the center co-ordinates of 2d polygon

int xpos = items[0]->getX();

int ypos = items[0]->getY();

//vector from point to center of polygon

float d = items[0]->getArc();

//current angle between vector and horizontal

float theta = atan2((float)ypos - y, (float)x - xpos);

float angle = float(theta * (180 / 3.14159));

items[0]->rotate(-angle - 90);

float DEG2RAD = (float) 3.14159/180;

angle = -angle +180;

//add one to angle

angle++;

//convert to radians

float degInRad = angle*DEG2RAD;

//set x and y position of polygon

items[0]->setPosition((float)(x + cos(degInRad)*100), (float)(y + sin(degInRad)*100));

}

the problem is, my code seems to work fine for a radius of 100 or greater, but the polygon doesn't rotate for a radius shorter than that.

Here is my code:

if (items[0] != NULL)

{

//the center co-ordinates of 2d polygon

int xpos = items[0]->getX();

int ypos = items[0]->getY();

//vector from point to center of polygon

float d = items[0]->getArc();

//current angle between vector and horizontal

float theta = atan2((float)ypos - y, (float)x - xpos);

float angle = float(theta * (180 / 3.14159));

items[0]->rotate(-angle - 90);

float DEG2RAD = (float) 3.14159/180;

angle = -angle +180;

//add one to angle

angle++;

//convert to radians

float degInRad = angle*DEG2RAD;

//set x and y position of polygon

items[0]->setPosition((float)(x + cos(degInRad)*100), (float)(y + sin(degInRad)*100));

}