ok here it is the collisionscode for circle collision
i use gludisk to create a circle

[pascal]
function check(x,y,size : single): boolean;
var d:single;
begin
d:=sqr(x)+sqr(y);
if d<=sqr(size+0.3) then result:=true else result:=false;
end;

procedure Render;
var i: integer;
rotation,xpos,ypos: double;
sphereobj: gluquadricobj;
begin
glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
glLoadidentity;

glpushmatrix();
gltranslatef(0,0,-6);

glcolor3f(1,1,1);
sphereobj:=glunewquadric();
gludisk(sphereobj,0,0.3,12,1);
gluDeleteQuadric(sphereObj);

glpopmatrix();

glpushmatrix();
gltranslatef(posx,posy,-6);

glcolor3f(1,1,1);
sphereobj:=glunewquadric();
gludisk(sphereobj,0,0.3,12,1);
gluDeleteQuadric(sphereObj);

glpopmatrix();

if check(posx,posy,0.3) then Form1.Caption:='Collision!' else Form1.Caption:=nope!';

SwapBuffers(myDC);
end;
[/pascal]

so how to make a slide collision?