Hands On DarkBASIC Pro - Digital Skills

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Resizing Objects FIG-31.38 Activity 31.16 In your previous program (object3D08.dbpro), add the line FIX OBJECT PIVOT 1 before the final FOR loop structure. How does this affect the rotation of the cube? Modify the program again so that the cube is only rotated to -45 o in the second FOR loop. How is the cube's rotation affected this time? It is possible to change the size of an object after it has been created. You have the option to resize one, two, or all three of the object’s dimensions. This allows you to make an object uniformly larger or smaller, or to distort the original shape by changing each dimension by differing amounts. The SCALE OBJECT Statement The SCALE OBJECT Statement Resizing an existing 3D object is achieved using the SCALE OBJECT statement which has the format shown in FIG-31.38. SCALE OBJECT objno , xperc , yperc , zperc In the diagram: , , , objno is the integer value previously assigned to the 3D object. xperc is a real number giving the new size of the object’s x dimension as a percentage of its original size in that dimension. For example, a value of 100.0 will retain the current size, while 200.0 would double the object’s length in the x dimension, and 50.0 would halve it. yperc is a real number giving the new size of the object’s y dimension as a percentage of its original size in that dimension. zperc is a real number giving the new size of the object’s z dimension as a percentage of its original size in that dimension. The program in LISTING-31.7 creates a sphere with a radius of 20 units. The sphere is then resized so that the x dimension is doubled and the z dimension reduced to 10 units. The new shape is then rotated about the y-axis. The user must press ESC to terminate the program. DarkBASIC Pro: 3D Primitives 775
LISTING-31.7 Resizing an Object REM *** Set display resolution *** SET DISPLAY MODE 1280,1024,32 REM *** Make and position the sphere ** MAKE OBJECT SPHERE 1, 20 POSITION OBJECT 1, 0,0,200 REM *** Resize sphere *** SCALE OBJECT 1, 200.0,100.0,50.0 REM *** Rotate shape *** DO TURN OBJECT RIGHT 1, 1.0 LOOP REM *** End program *** WAIT KEY END Activity 31.17 Type in and test the program in LISTING-31.6 (object3D09.dbpro). Modify the program so that a cone is used in place of the sphere. Showing and Hiding Objects FIG-31.39 The HIDE OBJECT Statement FIG-31.40 The SHOW OBJECT Statement Any 3D object is immediately visible from the moment it is created (assuming it’s within view), but it is possible to hide an object using the HIDE OBJECT statement, making it reappear later using the SHOW OBJECT command. The HIDE OBJECT Statement An object can be made invisible using the HIDE OBJECT statement which has the format shown in FIG-31.39. In the diagram: objno is the integer value previously assigned to the 3D object which is to be hidden. The SHOW OBJECT Statement An object which has been previously hidden can be made to reappear using the SHOW OBJECT statement which has the format shown in FIG-31.40. In the diagram: HIDE SHOW OBJECT objno OBJECT objno objno is the integer value previously assigned to the hidden 3D object which is to reappear. 776 DarkBASIC Pro: 3D Primitives
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Hands On DarkBASIC Pro A Self-Study
Page 3 and 4:
Copyright © Alistair Stewart 2006
Page 5 and 6:
The TURN OBJECT Statement . . . . .
Page 7 and 8:
The YROTATE CAMERA Statement . . .
Page 9 and 10: Chapter 35 Meshes and Limbs Meshes.
Page 11 and 12: The OBJECT IN SCREEN Statement . .
Page 13 and 14: The MAKE OBJECT COLLISION BOX State
Page 15 and 16: Adding MoveElevator() . . . . . . .
Page 17 and 18: The RANDOMIZE MATRIX Statement . .
Page 19 and 20: The MAKE MEMBLOCK FROM SOUND Statem
Page 21 and 22: The TRANSPOSE MATRIX4 Statement . .
Page 23 and 24: Networking the Game . . . . . . . .
Page 25 and 26: Acknowledgements I would like to th
Page 27 and 28: Syntax Diagrams make only a half-he
Page 29 and 30: The 3D World Introduction The Coord
Page 31 and 32: FIG-30.4 Points Determining the Pos
Page 33 and 34: FIG-30.6 Rotation A Cuboid is Rotat
Page 35 and 36: FIG-30.13 Varying the Polygons in a
Page 37 and 38: FIG-30.17 Lights Surface Normals FI
Page 39 and 40: � Space within the 3D world is me
Page 41 and 42: 3D Primitives Introduction FIG-31.1
Page 43 and 44: FIG-31.5 The MAKE OBJECT BOX Statem
Page 45 and 46: FIG-31.9 The MAKE OBJECT CONE State
Page 47 and 48: FIG-31.13 Creating a Triangle Objec
Page 49 and 50: FIG-31.16 The MOVE OBJECT Statement
Page 51 and 52: FIG-31.19 Possible Rotations about
Page 53 and 54: LISTING-31.3 Rotating an Object abo
Page 55 and 56: FIG-31.29 The PITCH OBJECT Statemen
Page 57 and 58: FIG-31.32 The POINT OBJECT Statemen
Page 59: LISTING-31.6 (continued) Local Axes
Page 63 and 64: Copying a 3D Object FIG-31.43 The C
Page 65 and 66: FIG-31.46 FIG-31.47 The OBJECT POSI
Page 67 and 68: FIG-31.49 The OBJECT ANGLE Statemen
Page 69 and 70: LISTING-31.11 (continued) Switching
Page 71 and 72: FIG-31.53 The SET GLOBAL OBJECT CRE
Page 73 and 74: Merging Primitives Introduction FIG
Page 75 and 76: FIG-31.58 As you've just discovered
Page 77 and 78: Solutions Activity 31.1 No solution
Page 79 and 80: Activity 31.20 The duplicated cube
Page 81 and 82: 796 DarkBASIC Pro: 3D Primitives
Page 83 and 84: Adding Texture Introduction FIG-32.
Page 85 and 86: FIG-32.3 An Image with Added Mipmap
Page 87 and 88: FIG-32.5 Floor Texturing FIG-32.6 T
Page 89 and 90: Seamless Tiling FIG-32.10 A Visible
Page 91 and 92: FIG-32.12 The PLAY ANIMATION TO IMA
Page 93 and 94: LISTING-32.6 (continued) Using the
Page 95 and 96: The SET OBJECT TRANSPARENCY Stateme
Page 97 and 98: LISTING-32.9 Using a Secondary Text
Page 99 and 100: LISTING-32.10 (continued) Using the
Page 101 and 102: FIG-32.24 A Transparent Cube Activi
Page 103 and 104: FIG-32.27 The FADE OBJECT Statement
Page 105 and 106: Images with an Alpha Channel Introd
Page 107 and 108: Creating a Complex 3D Shape Introdu
Page 109 and 110: The Code LISTING-32.15 Drawing the
Page 111 and 112:
LISTING-32.15 (continued) Drawing t
Page 113 and 114:
Sky Spheres FIG-32.32 Using a Sky S
Page 115 and 116:
Summary To cure the problem of an i
Page 117 and 118:
REM *** Create and texture plain ob
Page 119:
TEXTURE OBJECT GroundObj,CobbleImg
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