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pythonpython-3.xopenglctypespyglet

Pyglet OpenGL Setting Fog Color

I'd like to know how to set fog color using pyglet.gl.

I couldn't find information about fog color in the documentation, but I found this useful. However, the code I wrote 

pyglet.gl.glFogfv(gl.GL_FOG_COLOR, (0.5, 0.7, 1.0, 1.0))

produces the error: ctypes.ArgumentError: argument 2: <class 'TypeError'>: expected LP_c_float instance instead of tuple

I'm not sure how to give it a LP_c_float from my color tuple, as it is not found in pyglet.gl or in the above documentation.

Solution

  • The 2nd paramter of pyglet.gl.glFogfv is an array of 4 floats, sp you have to create an ctypes array by (GLfloat * 4), see pyglet.gl.glFogfv:

    pyglet.gl.glFogfv(gl.GL_FOG_COLOR, (GLfloat * 4)(0.5, 0.7, 1.0, 1.0))

    See ctypes — A foreign function library for Python - Arrays:

    Arrays are sequences, containing a fixed number of instances of the same type.

    The recommended way to create array types is by multiplying a data type with a positive integer:

    TenPointsArrayType = POINT * 10