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In pyglet, I want to create an image buffer in memory, then set the bytes manually, then draw it. I tried making a 3x3 red square like this in my draw() function:

imageData = pyglet.image.ImageData(3, 3, 'RGB', [1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0 ])
imageData.blit(10, 10)

...but at runtime, Python complains:

ctypes.ArgumentError: argument 9: <type 'exceptions.TypeError'>: wrong type

Is this the right approach? Am I missing a step? How can I fix this?

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    \$\begingroup\$ Are you sure the error corresponds with the code you have posted above? I do not know python but I don't see anything you have posted above with 9 arguments. AFAIK it looks like one of your arguments are not using the correct type. \$\endgroup\$ Commented May 21, 2013 at 23:53
  • \$\begingroup\$ I agree with Code Assassin. The error seems to have to do with what you typed, wrong arguments? \$\endgroup\$ Commented May 22, 2013 at 0:16
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    \$\begingroup\$ Well, I guess I am just assuming it is the problem as the error doesn't show up if I comment those lines... pastebin.com/iveDhYcB is the full source \$\endgroup\$ Commented May 22, 2013 at 0:38

1 Answer 1

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Yes, you can do this, but as the error tells you, you must use ctypes instead of Python types for it.

RGB values are unsigned byte triplets, which means c_ubyte in ctypes, also available in pyglet.gl as GL_ubyte. So you can do this:

pixels = [
    255, 0, 0,      0, 255, 0,      0, 0, 255,     # RGB values range from
    255, 0, 0,      255, 0, 0,      255, 0, 0,     # 0 to 255 for each color
    255, 0, 0,      255, 0, 0,      255, 0, 0,     # component.
]
rawData = (GLubyte * len(pixels))(*pixels)
imageData = pyglet.image.ImageData(3, 3, 'RGB', rawData)

The above is the recommended ctypes syntax, which generates an array of GLubyte with the right size and then populates it with your pixel data.

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  • \$\begingroup\$ I've changed your colors a little from all red to illustrate the pixel order on rendering. \$\endgroup\$ Commented Nov 12, 2013 at 20:51

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