[bmx] Shadows by SillyPutty [ 1+ years ago ]

[BlitzBot]

Title : Shadows
Author : SillyPutty
Posted : 1+ years ago

Description : How to draw 2D shadows

Code :

Code: BlitzMax

1. SuperStrict
2.  
3. Graphics 640,480
4.  
5. Global xpos:Float
6. Global ypos:Float
7. Global angle:Float
8. Global Falloff:Int = 1000
9.  
10. SetClsColor 125,125,125
11.  
12. Function DrawShadowCaster(x1:Float,y1:Float,x2:Float,y2:Float)
13.        
14.         Local shadowCaster:Float[8]
15.         Local lightAngle:Float
16.        
17.         lightAngle = ATan2(xpos-x2,ypos-y2)
18.  
19.         SetColor 0,0,0
20.        
21.         shadowCaster[0] = x1
22.         shadowCaster[1] = y1
23.         shadowCaster[2] = x2
24.         shadowCaster[3] = y2
25.         shadowCaster[4] = x2-Sin(lightAngle)*Falloff
26.         shadowCaster[5] = y2-Cos(lightAngle)*Falloff
27.  
28.         lightAngle = ATan2(xpos-x1,ypos-y1)
29.  
30.         shadowCaster[6] = x1-Sin(lightAngle)*Falloff
31.         shadowCaster[7] = y1-Cos(lightAngle)*Falloff
32.        
33.         DrawPoly ShadowCaster
34.         SetColor 255,255,255
35.         DrawLine x1,y1,x2,y2
36.        
37. End Function
38.  
39.  
40. While not KeyDown(KEY_ESCAPE)
41.        
42.        
43.         xpos = MouseX()
44.         ypos = MouseY()
45.        
46.         SetColor 255,255,0
47.         DrawOval xpos-5,ypos-5,10,10
48.        
49.         ' box
50.         DrawShadowCaster 200,200,400,200
51.         DrawShadowCaster 200,200,200,100
52.         DrawShadowCaster 200,100,400,100
53.         DrawShadowCaster 400,100,400,200
54.        
55.         'wall
56.         DrawShadowCaster 200,400,400,400
57.  
58.         DrawLine 200,200,400,200
59.         DrawLine 200,200,200,100
60.         DrawLine 200,100,400,100
61.         DrawLine 400,100,400,200
62.        
63.         Flip
64.         Cls
65. Wend

Comments :


SillyPutty(Posted 1+ years ago)

 Thanks to Cyanide who gave me an example about a year ago on how to do this, since then I lost the code he gave me, but knocked this one up from what I learnt from his method. Adding it here so I dont lose the code again