[HOpenGL] GLSL interface

[Claude Heiland-Allen]

On 20/02/13 17:26, Daniel Bergey wrote:
> What is the recommended way to create and use a Shader object?

Personally I tend to use OpenGLRaw package or OpenGLRaw21 package, as
OpenGL package diverges from all the useful non-Haskell tutorials and
documentation by a wide margin, and OpenGL package doesn't yet support
such useful things as geometry shaders.  Anyway, usage is mostly via the
ObjectName/StateVar interface:

> Graphics.Rendering.OpenGL.GL.Shaders.Shaders has a function createShader
> which looks good, but is not exported.  Similar not-exported functions
> seem to exist for the Program type.

-- untested code
do
  [vert] <- genObjectNames 1
  [frag] <- genObjectNames 1
  [prog] <- genObjectNames 1
  shaderSource vert $= ["void main() { gl_Position = ftransform(); }"]
  shaderSource frag $= ["void main() { gl_FragColor = vec4(1.0); }"]
  compileShader vert
  compileShader frag
  attachedShaders prog $= ([vert], [frag])
  linkProgram prog
  debugPrint =<< get (programInfoLog prog)
  currentProgram $= Just prog
  -- draw using shader here
  currentProgram $= Nothing

> If there's still work do be done on this part of the library, I can
> to test out some code and submit a pull request.


Claude
-- 
http://mathr.co.uk