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4.3 collision detection
1. Microsoft® Small Basic Collision Detection Estimated time to complete this lesson: 1 hour
2. Collision Detection In this lesson, you will learn about: Using the concept of collision detection in games.
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5. Hit the Target – The Game You use the logic of collision detection to detect the collision between the turtle and the target. The game ends as soon as the two objects collide. The game involves two objects: the turtle and the target. The player has to make the turtle hit the target by entering the correct angle and the distance. Now that you have understood the concept of collision detection in games, let’s make a game that uses the logic of collision detection.
10. Next, use the Controls object to add a click button and text box and set the size of control buttons.
11. Use the Shapes object to add an image of the shape, and to move and animate the shape and set its opacity level.
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13. It’s Time to Apply Your Learning… Using the concept of collision detection, create a game that involves two objects: a bucket and apples. The apples fall randomly from the top of the screen. The player tries to catch the apples in the bucket. The game runs for 30 seconds. Include a score board to display the total number of apples caught by the player in 30 seconds. Your game should look somewhat like the following.
Editor's Notes
Code:' Copyright (c) Microsoft Corporation. All rights reserved.GraphicsWindow.Hide()gw = 620gh = 450GraphicsWindow.BackgroundColor = "LightBlue"GraphicsWindow.CanResize = "False"GraphicsWindow.Width = gwGraphicsWindow.Height = ghGraphicsWindow.Top = ( Desktop.Height - gh ) / 2GraphicsWindow.Left = ( Desktop.Width - gw ) / 2GraphicsWindow.Title = "Hit the Target"GraphicsWindow.Show()Turtle.Hide()rx = 40ry = 20turtlex = 315turtley = 300width = 550height = 390ScoreboxX = 400Enterkey = "Return"target = 10life = 3score = 0GraphicsWindow.FontSize = 30GraphicsWindow.DrawText(100, 200, "Press ENTER to start the game!")GraphicsWindow.KeyDown = OnpressSub Onpress enter = enter + 1If GraphicsWindow.LastKey = Enterkey And enter = 1 ThenGraphicsWindow.Clear()GraphicsWindow.FontSize = 12 GUI()MovingShape()ScoreShow()Controls.ButtonClicked = hitClickEndIfEndSubSub hitClick angle = Math.Round(Controls.GetTextBoxText(angletxt)) distance = Math.Round(Controls.GetTextBoxText(distancetxt)) clicked = Controls.GetButtonCaption(Controls.LastClickedButton) If clicked = "Hit" ThenGraphicsWindow.PenWidth = 0Turtle.Angle = angleTurtle.Move(distance)If Turtle.x > x and Turtle.x < x + 93 and Turtle.y > y and Turtle.y < y + 96 ThenShapes.HideShape(target) score = score + 10 scoreshow()Program.Delay(500)If target = score ThenGameEnd()EndIfControls.SetTextBoxText(angletxt, "")Controls.SetTextBoxText(distancetxt, "")MovingShape()ElseProgram.Delay(1000)If life > 1 ThenGraphicsWindow.ShowMessage("Click Ok to continue the game","Reset") clicked = "Reset"Else GameEnd()EndIfEndIfEndIfIf clicked = "Reset" Then life = life - 1If score >= 10 Then score = score - 5EndIfscoreshow()Controls.SetTextBoxText(angletxt, "")Controls.SetTextBoxText(distancetxt, "")MovingShape() If life < 1 ThenGameEnd()EndIfEndIfEndSubSub GUI image = Program.Directory + "cartoon.gif" GraphicsWindow.DrawRectangle(rx, ry, width, height) target = Shapes.AddImage(image) GraphicsWindow.BrushColor = "Black"Shapes.Move(target, 100, 50) Turtle.Show()Turtle.X = turtlexTurtle.y = turtleyTurtle.Angle = 0GraphicsWindow.DrawText(rx + 5, height - 10, "Enter Angle:")angletxt = Controls.AddTextBox(turtlex - 190, Turtley + 70)Controls.SetSize(angletxt, 40, 30) GraphicsWindow.DrawText(rx + 130, height - 10, "Enter Distance:")distancetxt = Controls.AddTextBox(turtlex - 50, Turtley + 70)Controls.SetSize(distancetxt, 40, 30) firebutton = Controls.AddButton("Hit", turtlex + 20, Turtley + 70) Controls.SetSize(firebutton, 80, 30) EndsubSub MovingShapeShapes.ShowShape(target)Turtle.x = turtlexTurtle.Y = turtleyTurtle.Angle = 0 x = Math.GetRandomNumber(450) y = Math.GetRandomNumber(80)If x <= 40 Then x = 40Shapes.Animate(target, x, y, 1000)ElseIf y <= 20 Then y = 20Shapes.Animate(target, x, y, 1000)Else Shapes.Animate(target, x, y, 1000)EndIfEndSubSub GameEndGraphicsWindow.ShowMessage("Your score is:" + score, "Game Over") Program.End()EndSubSub ScoreShowGraphicsWindow.FontSize = 14GraphicsWindow.BrushColor = "Gray"GraphicsWindow.FillRectangle(ScoreboxX + 50, ScoreboxX - 65, 135, 70) GraphicsWindow.BrushColor = "White"GraphicsWindow.DrawText(ScoreboxX + 60, ScoreboxX - 55, "Score :")GraphicsWindow.DrawText(ScoreboxX + 110, ScoreboxX - 55, score)GraphicsWindow.DrawText(ScoreboxX + 60, ScoreboxX - 20, "Life :")GraphicsWindow.DrawText(ScoreboxX + 110, ScoreboxX - 20, life) EndSub
