Michael Fabain Dirks
101 lines
2.8 KiB
HTML
101 lines
2.8 KiB
HTML
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<title>Blitz3D Docs</title>
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<link rel=stylesheet href=../css/commands.css type=text/css>
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<h1>WritePixelFast x,y,rgb,[buffer]</h1>
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<h1>Parameters</h1>
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<table>
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x - y-coordinate of pixel
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y - y-coordinate of pixel
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argb - argb colour value of pixel (alpha, red, green, blue)
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buffer (optional) - name of buffer to write colour value to, e.g. BackBuffer()
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</td>
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<h1>Description</h1>
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Writes a colour value to either the current buffer or the specified buffer.
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IMPORTANT:
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You *must* use this command on a locked buffer, otherwise the command will fail. See LockBuffer.
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Also, you must make sure that the coordinates that you are writing to are valid, otherwise you will end up overwriting other areas of memory.
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WARNING:
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By not following the above advice, you may cause your computer to crash.
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See also: Plot, WritePixel.
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</td>
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</table>
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<h1><a href=../2d_examples/WritePixelFast.bb>Example</a></h1>
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; ReadPixelFast/WritePixeFast Example
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; -----------------------------------
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Graphics 640,480,16
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Print "Press a key to read color values"
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WaitKey()
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; Load and draw an image on to the screen - can be anything
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pic=LoadImage("media/blitz_pic.bmp")
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DrawImage pic,0,0
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; Initialise an array big enough to fit all the color information of the screen
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Dim pix(GraphicsWidth(),GraphicsHeight())
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; Lock buffer before using ReadPixelFast
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LockBuffer
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; Use ReadPixel to get all the color information of the screen
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For y=0 To GraphicsHeight()
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For x=0 To GraphicsWidth()
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pix(x,y)=ReadPixelFast(x,y)
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Next
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Next
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; Lock buffer after using ReadPixelFast
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UnlockBuffer
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Cls
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Locate 0,0
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Print "Press a key to write pixels"
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Print "Once this has finished, you can then press a key to end the program"
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WaitKey()
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; Lock buffer before using WritePixelFast
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LockBuffer
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; Use WritePixel to redraw the screen using the color information we got earlier
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For y=0 To GraphicsHeight()
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For x=0 To GraphicsWidth()
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WritePixelFast x,y,pix(x,GraphicsHeight()-y) ; get y array value in backwards order, to flip screen
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Next
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Next
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; Unlock buffer after using WritePixelFast
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UnlockBuffer
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WaitKey()
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</td>
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</table>
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<br>
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<a target=_top href=../index.htm>Index</a><br>
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<br>
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Click <a href=http://www.blitzbasic.co.nz/b3ddocs/command.php?name=WritePixelFast&ref=comments target=_blank>here</a> to view the latest version of this page online</body>
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