Hands On DarkBASIC Pro - Digital Skills

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FIG-31.57 The PERFORM CSG UNION Statement LISTING-31.13 Creating a New 3D Shape using Union This program positions the camera which is responsible for the picture we see on the screen. Full details of camera usage are covered in Chapter 33. In the diagram: objno1 is an integer value specifying the ID of the first 3D object to be used in the union. objno2 is an integer value specifying the ID of the second 3D object to be used in the union. The statement modifies the shape of objno1 without affecting objno2. Normally, the programmer would delete the second object once the union is completed. The program in LISTING-31.13 demonstrates the union of a cube and a box. After the box has been deleted, the resulting shape is then rotated about its local x and y axes. REM *** Set screen resolution and background *** SET DISPLAY MODE 1280,1024,32 COLOR BACKDROP 0 BACKDROP ON REM *** Position camera *** AUTOCAM OFF POSITION CAMERA 0,0,-100 REM *** Create two shapes used *** MAKE OBJECT CUBE 1,40 MAKE OBJECT BOX 2,10,30,10 POSITION OBJECT 2,0,15,0 REM *** Let viewer see position of shapes *** WAIT KEY REM *** Union shapes *** PERFORM CSG UNION 1,2 REM *** Remove object 2 *** DELETE OBJECT 2 REM *** Rotate new shape *** DO TURN OBJECT LEFT 1,1.0 PITCH OBJECT UP 1,1.0 LOOP REM *** End program *** END Activity 31.28 PERFORM CSG UNION objno1 objno2 Type in and test the program given in LISTING-31.13 (object3D16.dbpro). Try changing the second object to a sphere of diameter 10 and change the POSITION OBJECT statement to read POSITION OBJECT 2, 0, 25, 0 DarkBASIC Pro: 3D Primitives 789 ,
FIG-31.58 As you've just discovered, the UNION statement only works predictably with cubes and boxes. Other shapes give unpredictable results (although the cone is close). The PERFORM CSG DIFFERENCE Statement The PERFORM CSG DIFFERENCE Statement FIG-31.59 The PERFORM CSG INTERSECTION Statement The PERFORM CSG DIFFERENCE statement removes from object 1 the volume it shares in common with object 2. The statement has the format shown in FIG-31.58. In the diagram: objno1 is an integer value specifying the ID of the first 3D object to be used in the difference operation. objno2 is an integer value specifying the ID of the second 3D object to be used in the difference operation. As before, the second object is unaffected by the operation and would normally be deleted. Also, we are again restricted to cubes and boxes if we are to obtain consistent results. Activity 31.29 Restore your last project to its original code (as shown in LISTING-31.13). Change the union operation to a difference operation and observe the new shape created. Modify the width and depth of the box to be 35. The PERFORM CSG INTERSECTION Statement The PERFORM CSG INTERSECTION statement does not perform intersection as defined at the beginning of this chapter, but it does create a different shape from that produced by the PERFORM CSG DIFFERENCE statement and so is worth looking at. The statement has the format shown in FIG-31.59. In the diagram: PERFORM CSG DIFFERENCE objno1 objno2 PERFORM CSG INTERSECTION objno1 objno2 objno1 is an integer value specifying the ID of the first 3D object to be used in the intersection operation. objno2 is an integer value specifying the ID of the second 3D object to be used in the intersection operation. Again, the second object would normally be deleted and we are restricted to cubes and boxes if we are to obtain predictable results. 790 DarkBASIC Pro: 3D Primitives , ,
Page 1 and 2:
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 and 60: LISTING-31.6 (continued) Local Axes
Page 61 and 62: LISTING-31.7 Resizing an Object REM
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: Merging Primitives Introduction FIG
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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