[bb] Fade by skidracer [ 1+ years ago ]

[BlitzBot]

Title : Fade
Author : skidracer
Posted : 1+ years ago

Description : Not exactly fast, but probably the most optimal way to fade the screen in blitz currently.

Code :

Code: BlitzBasic

1. ; fade.bb
2. ; by simon@acid.co.nz
3.  
4. ; as readpixel is slow this fade routine copies the graphics buffer to a bank
5. ; and uses the bank as a pixel source for subsequent calls to fade
6.  
7. Graphics 640,480,32
8.  
9. While Not MouseHit(1)
10.         Color Rnd(255),Rnd(255),Rnd(255)
11.         Line Rnd(640),Rnd(480),Rnd(640),Rnd(480)
12. Wend
13. gfxbank=GrabBank()
14.  
15. ; use double buffering for clean fade
16.  
17. SetBuffer BackBuffer()
18. For i=1 To 32
19.         Fade(gfxbank)
20.         Flip
21. Next
22. FreeBank gfxbank
23.  
24. MouseWait
25. End    
26.  
27. Function GrabBank()
28.         w=GraphicsWidth()
29.         h=GraphicsHeight()
30.         bank=CreateBank(w*h*4) 
31.         gbuffer=GraphicsBuffer()
32.         LockBuffer gbuffer
33.         For y=0 To h-1
34.                 For x=0 To w-1
35.                         PokeInt bank,o,ReadPixelFast(x,y)
36.                         o=o+4
37.                 Next
38.         Next
39.         UnlockBuffer gbuffer   
40.         Return bank
41. End Function
42.  
43. Function Fade(bank)
44.         w=GraphicsWidth()-1
45.         h=GraphicsHeight()-1
46.         gbuffer=GraphicsBuffer()
47.         LockBuffer gbuffer
48.         For y=0 To h
49.                 For x=0 To w
50.                         rgb=PeekInt(bank,o)
51.                         d=(rgb Shr 3) And $1f1f1f
52.                         If d=0 d=rgb
53.                         rgb=rgb-d
54.                         WritePixelFast x,y,rgb
55.                         PokeInt(bank,o,rgb)
56.                         o=o+4
57.                 Next
58.         Next
59.         UnlockBuffer gbuffer   
60. End Function

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