private static ObjectAction GetShootBulletAction( Dictionary <string, DTDanmakuImage> spriteNameToImageDictionary, Dictionary <string, EnemyObjectTemplate> enemyObjectTemplates, GuidGenerator guidGenerator) { string angleVariable = guidGenerator.NextGuid(); string shootCooldownVariable = guidGenerator.NextGuid(); ObjectAction initializeAngleVariable = ObjectActionGenerator.DoOnce( ObjectAction.SetNumericVariable(angleVariable, MathExpression.RandomInteger(360 * 1000))); ObjectAction updateAngleVariableAction = ObjectAction.Union( ObjectAction.SetNumericVariable( angleVariable, MathExpression.Add(MathExpression.Variable(angleVariable), MathExpression.Multiply(MathExpression.Constant(150), MathExpression.ElapsedMillisecondsPerIteration()))), ObjectAction.Condition( condition: BooleanExpression.GreaterThan(MathExpression.Variable(angleVariable), MathExpression.Constant(360 * 1000)), action: ObjectAction.SetNumericVariable(angleVariable, MathExpression.Subtract(MathExpression.Variable(angleVariable), MathExpression.Constant(360 * 1000)))), ObjectAction.Condition( condition: BooleanExpression.GreaterThan(MathExpression.Variable(angleVariable), MathExpression.Constant(360 * 1000)), action: ObjectAction.SetNumericVariable(angleVariable, MathExpression.Constant(0)))); ObjectAction createBulletAction = ObjectAction.Condition( condition: BooleanExpression.Variable("can shoot"), action: SpawnBullet( bulletDirectionInMillidegrees: MathExpression.ParentVariable(angleVariable), spriteNameToImageDictionary: spriteNameToImageDictionary, enemyObjectTemplates: enemyObjectTemplates, guidGenerator: guidGenerator)); IMathExpression shootCooldownInMillis = MathExpression.Constant(50); ObjectAction startCooldownAction = ObjectAction.SetNumericVariable(shootCooldownVariable, shootCooldownInMillis); ObjectAction decrementCooldownAction = ObjectAction.SetNumericVariable(shootCooldownVariable, MathExpression.Subtract(MathExpression.Variable(shootCooldownVariable), MathExpression.ElapsedMillisecondsPerIteration())); ObjectAction createBulletWhenCooldownFinishedAction = ObjectAction.Condition( condition: BooleanExpression.LessThanOrEqualTo(MathExpression.Variable(shootCooldownVariable), MathExpression.Constant(0)), action: ObjectAction.Union(startCooldownAction, createBulletAction)); return(ObjectAction.Union( initializeAngleVariable, updateAngleVariableAction, ObjectActionGenerator.DoOnce(startCooldownAction), decrementCooldownAction, createBulletWhenCooldownFinishedAction)); }