[bb] ImageToBank, BankToImage functions by Perturbatio [ 1+ years ago ]

[BlitzBot]

Title : ImageToBank, BankToImage functions
Author : Perturbatio
Posted : 1+ years ago

Description : A simple example of loading from and storing images in banks

Code :

Code: BlitzBasic

1. Graphics 640,480
2. SetBuffer BackBuffer()
3.  
4. bBank = CreateBank(5)
5. iImage = LoadImage("testin.png")
6.  
7. ImageToBank(bBank, iImage)
8.  
9. newImage = BankToImage(bBank)
10. DrawImage newImage, 0,0
11.  
12.  
13. Flip
14. WaitKey()
15.  
16. FreeBank bBank
17. FreeImage newImage
18. FreeImage iImage
19. End
20.  
21.  
22. ;;;;;;;;;;;;;;;;;;;;;;;;
23. ; Function ImageToBank ;
24. ;;;;;;;;;;;;;;;;;;;;;;;;
25. ;Accepts a bank which will be resized to store the data, and an image to store,
26. ;optional parameter is the AlphaFlag (currently irrelevant)
27. ;Returns the error code.
28. Function ImageToBank(bankImage, bufferImage, iAlphaFlag=0)
29. bufOldBuffer = GraphicsBuffer();get the handle for the current buffer
30. Error = 0; Error 0 = no error, error 1 = image size invalid
31.  
32. ;Check the image dimensions, if invalid then exit function with errorcode 1
33. If (ImageWidth(bufferImage)<1) Or (ImageHeight(bufferImage)<1) Then
34.         Error = 1
35.         Goto EndBufferToBank
36. EndIf
37.  
38. ;get the total number of bytes the image makes up
39. SizeOfImage = ImageWidth(bufferImage)*ImageHeight(bufferImage)
40.  
41. ResizeBank bankImage, (SizeOfImage*4) + 9 ;(4 bytes per int for the image info + 9 extra bytes for header)
42.  
43. PokeInt bankImage,0,ImageWidth(bufferImage);store the width in the bank
44. PokeInt bankImage,4,ImageHeight(bufferImage);store the height
45.  
46. ;store other info in byte 8 (the ninth byte)
47. iByte8 = %00000000
48. If iAlphaFlag Then iByte8 = iByte8 Or %00000001 ; OR the first bit to 1 if it has an alpha mask
49.  
50. PokeByte bankImage,8,iByte8 ;store iByte8
51.  
52. ;DebugLog "Byte 8: " + iByte8
53.  
54. iBankPointer = 9
55. SetBuffer ImageBuffer(bufferImage)
56. LockBuffer ImageBuffer(bufferImage)
57. For iLoopX = 0 To ImageWidth(bufferImage)-1
58.         For iLoopY = 0 To ImageHeight(bufferImage)-1
59.                 PokeInt bankImage,ibankPointer, ReadPixelFast(iLoopX,iLoopY)
60.                 iBankPointer = iBankPointer + 4;increment by 4 each time since it is an int we are poking
61.         Next
62. Next
63. UnlockBuffer ImageBuffer(bufferImage)
64. SetBuffer bufOldBuffer ; restore the buffer
65.  
66. .EndBufferToBank
67. Return Error
68. End Function
69.  
70.  
71. ;;;;;;;;;;;;;;;;;;;;;;;;
72. ; Function BankToImage ;
73. ;;;;;;;;;;;;;;;;;;;;;;;;
74. ; Accepts a bank that has previously had its' data set with ImageToBank
75. ; Returns an image
76. Function BankToImage(bankImage)
77. bufOldBuffer = GraphicsBuffer()
78. iWidth = PeekInt(bankImage,0)
79. iHeight = PeekInt(bankImage,4)
80. iiByte8 = PeekByte(bankImage,5)
81. ;get the length of the data block
82. SizeOfData = iWidth*iHeight
83. imgReturn = CreateImage(iWidth,iHeight)
84.  
85. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
86. ;Insert code To process iByte8
87. ; NOTE FOR ALPHA: if ((BIT0) And %00000001) = 1 then (process alpha info)
88. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
89.  
90. iBankPointer = 9
91.  
92. SetBuffer ImageBuffer(imgReturn)
93. LockBuffer ImageBuffer(imgReturn)
94. For iLoopX = 0 To ImageWidth(imgReturn)-1
95.         For iLoopY = 0 To ImageHeight(imgReturn)-1
96.                 WritePixelFast(iLoopX,iLoopY,PeekInt(bankImage,iBankPointer))
97.                 iBankPointer = iBankPointer + 4;increment by 4 each time since it is an int we are peekin
98.         Next
99. Next
100. UnlockBuffer ImageBuffer(imgReturn)
101. SetBuffer bufOldBuffer
102.  
103.  
104. Return imgReturn
105.  
106.  
107. End Function
108.  
109.  
110. ; The following is a description of the format in which the information is stored in the bank
111. ; -------------------------------------------------------------------------------------------
112. ;
113. ; Bytes 0-3 contains the width of the image (4-byte integer) must not be less than 1
114. ; Bytes 4-7 contains the height of the image (4-byte integer) must not be less than 1
115. ; Bit 0 of Byte 8 describes whether the image has an alpha mask (0=no, 1=yes)
116. ;               may contain more information at a later date
117. ;
118. ; NOTE FOR ALPHA: if ((BIT0) And %00000001) = 1 then (process alpha info)
119. ;
120. ; Bytes onward from 9 descrive the image as integers, because the length of this can be calculated
121. ; by multiplying the width by the height, there is no need for a terminator

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