Concentration Effect

let CSD = GetCurrentScriptDirectory;
let petal = CSD ~ "petal.png";
LoadGraphic(petal);

task Concentration03(Frame){
	loop(Frame/3-30){
		cherry(30,1,rand(0,359));
		wait(3);
	}

	task cherry(radius,speed,angle){
		let obj = Obj_Create(OBJ_EFFECT);
		let xspin = rand(-0.01,0.01);
		let yspin = rand(-0.01,0.01);
		let zspin = rand(-0.01,0.01);

		Obj_SetPosition(obj,GetX+radius*cos(angle),GetY+radius*sin(angle));
		Obj_SetAngle(obj,atan2(GetY-Obj_GetY(obj),GetX-Obj_GetX(obj)));
		Obj_SetSpeed(obj,speed);

		ObjEffect_SetTexture(obj,petal);
		Obj_SetAlpha(obj,128);
		ObjEffect_SetPrimitiveType(obj,PRIMITIVE_TRIANGLESTRIP);
		ObjEffect_CreateVertex(obj,4);

		ObjEffect_SetVertexUV(obj,0,0,0);
		ObjEffect_SetVertexUV(obj,1,27,0);
		ObjEffect_SetVertexUV(obj,2,0,11);
		ObjEffect_SetVertexUV(obj,3,27,11);

		ObjEffect_SetVertexXY(obj,0,-13.5,-5.5);
		ObjEffect_SetVertexXY(obj,1,13.5,-5.5);
		ObjEffect_SetVertexXY(obj,2,-13.5,5.5);
		ObjEffect_SetVertexXY(obj,3,13.5,5.5);

		while(!Obj_BeDeleted(obj)){
			ObjEffect_SetAngle(obj,xspin,yspin,zspin);
			yield;
		}
		wait(radius/speed);
		Obj_Delete(obj);
	}
}

function wait(w){ loop(w){ yield;}}