[bb] Obscurer example - With viewangle by Jeppe Nielsen [ 1+ years ago ]

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Title : Obscurer example - With viewangle
Author : Jeppe Nielsen
Posted : 1+ years ago

Description : An example showing how to calculate if entities can see each other

Code :

Code: BlitzBasic

1. ;Obscurer example by Jeppe Nielsen 2004
2. ;nielsen_jeppe@hotmail.com
3.  
4. Graphics3D 800,600,16,2
5.  
6. viewangle#=45
7.  
8. CreateLight(2)
9.  
10. cam=CreateCamera()
11. PositionEntity cam,0,40,0
12. RotateEntity cam,90,0,0
13. CameraZoom cam,2
14.  
15. obj1=CreateCone()
16. RotateMesh obj1,-90,0,0
17.  
18. view=CreateCone(16,1,obj1)
19.  
20. RotateMesh view,-90,0,0
21. PositionMesh view,0,0,1
22. ScaleMesh view,0.5,0.5,0.5
23. EntityColor view,128,128,0
24. EntityAlpha view,0.8
25. UpdateViewCone(view,10,viewangle#)
26.  
27. obj2=CreateCube()
28.  
29. cube1=CreateCube()
30. EntityColor cube1,255,255,0
31. EntityPickMode cube1,3
32.  
33. cube2=CreateCube()
34. EntityColor cube2,255,255,0
35. EntityPickMode cube2,3
36.  
37. cube3=CreateCube()
38. EntityColor cube3,255,255,0
39. EntityPickMode cube3,3
40.  
41.  
42. Repeat
43.  
44. If KeyDown(203)
45.  
46.         TurnEntity obj1,0,2,0
47.  
48. EndIf
49.  
50. If KeyDown(205)
51.  
52.         TurnEntity obj1,0,-2,0
53.  
54. EndIf
55.  
56. If KeyDown(78)
57.  
58.         viewangle#=viewangle#+1
59.         If viewangle#>179
60.                 viewangle#=179
61.         EndIf
62.         UpdateViewCone(view,10,viewangle#)     
63.  
64. EndIf
65.  
66. If KeyDown(74)
67.  
68.         viewangle#=viewangle#-1
69.         If viewangle#<15
70.                 viewangle#=15
71.         EndIf
72.         UpdateViewCone(view,10,viewangle#)     
73.  
74. EndIf
75.  
76. an#=MilliSecs()/20
77. PositionEntity obj2,Sin(an#)*10,0,Cos(an#)*10
78.  
79. an#=MilliSecs()/50
80. PositionEntity cube1,Sin(an#)*6,0,Cos(an#)*6
81.  
82. PositionEntity cube2,Sin(an#+120)*6,0,Cos(an#+120)*6
83. PositionEntity cube3,Sin(an#+240)*6,0,Cos(an#+240)*6
84.  
85. RenderWorld
86.  
87. If CanSeeObject(obj1,obj2,viewangle)
88.  
89.         Color 255,255,255
90.         Text 400,200,"I see it :)",1
91.         CameraProject cam,EntityX(obj1),EntityY(obj1),EntityZ(obj1)
92.         x1=ProjectedX()
93.         y1=ProjectedY()
94.         CameraProject cam,EntityX(obj2),EntityY(obj2),EntityZ(obj2)
95.         x2=ProjectedX()
96.         y2=ProjectedY()
97.         Color Rnd(255),Rnd(255),Rnd(255)
98.         Line x1,y1,x2,y2
99.        
100.  
101. EndIf
102.  
103. Color 255,255,255
104. Text 400,10,"Left/right to rotate observer",1
105. Text 400,30,"+ / - to change view angle",1
106. Text 400,50,"Yellow boxes obscurers the view",1
107. Text 400,70,"View angle : "+viewangle,1
108.  
109. Flip
110.  
111. Until KeyDown(1)
112. End
113.  
114. Function UpdateViewCone(cone,depth#,angle#)
115.        
116.         sc#=Tan(angle/2)*depth*2
117.        
118.         ScaleEntity cone,sc,sc,depth#
119.        
120. End Function
121.  
122. Function CanSeeObject(obj1,obj2,angle#=90)
123.  
124. dist#=EntityDistance(obj1,obj2)
125. dx#=(EntityX(obj2,1)-EntityX(obj1,1)) / dist
126. dy#=(EntityY(obj2,1)-EntityY(obj1,1)) / dist
127. dz#=(EntityZ(obj2,1)-EntityZ(obj1,1)) / dist
128.  
129. TFormVector 0,0,1,obj1,0
130.  
131. ;dot product:
132. dot#=dx*TFormedX()+dy*TFormedY()+dz*TFormedZ()
133.  
134. If ACos(dot#)<angle/2
135.        
136.         Return EntityVisible(obj1,obj2)
137.        
138. EndIf
139.  
140. End Function

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