January 2016 - HOpenGL

Re: [HOpenGL] [Haskell-cafe] Merging the OpenGLRaw and gl packages
by Sven Panne 11 Jan '16

11 Jan '16

2016-01-10 21:56 GMT+01:00 Oliver Charles <ollie(a)ocharles.org.uk>: > I'm not really convinced by this. This change introduced an inconsistency > and duplication, but doesn't really solve the problem. I already found > another enum that has this problem (GL_LINEAR), and I hardly suggest > introducing GL_LINEAR to work around that. > GL_LINEAR as a parameter is sometimes used as a GLenum (see e.g. glBlitFramebuffer) and sometimes as a GLint (see e.g. glGetTextureParameteriv), and there is no clear winner. > While I agree that OpenGL is barely typed *statically*, there is a lot of > runtime type checking. In practice o always develop with KHR debug as an > extension or replay via apitrace, and this always checks ebum values for > validity. > Yes, using a debug context + glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS) + glDebugMessageCallback during development is always a good idea. Apart from the stateful nature of the API ("this and that is only allowed when we are in state foobar etc."), the whole notion of profiles and extensions makes it fundamentally impossible to have a 100% type-safe API. You can't even e.g. statically tell which set of enums is allowed as a parameter for a given function. > I think OpenGLRaw would be more practical with gl-style polymorphic > patterns > As I said in my previous email: Whenever you use the OpenGL API directly (be it via OpenGLRaw or gl), you *will* have lots of 'fromIntegral's, and the patterns don't make much of a difference. A quick grep showed that your SSAO-example project has 33 fromIntegral calls, and only 2 are caused by the patterns being monomorphic. The luminance package is even more extreme in this respect: It contains 188 fromIntegral calls, and only 2 are caused by the monomorphic patterns. (I may be off by small amount, but that doesn't really change the fact.) So in a nutshell: This is a non-issue in practice and mostly a bikeshedding discussion, and I won't change that aspect of the binding. Cheers, S.

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Re: [HOpenGL] [Haskell-cafe] Merging the OpenGLRaw and gl packages
by Sven Panne 11 Jan '16

11 Jan '16

2015-10-01 11:01 GMT+02:00 Oliver Charles <ollie(a)ocharles.org.uk>: > [...] However, it's a lot more significant if you want to do something > like: > > foo x = doSomething (case x of ...) > > Without pattern synonyms, you either have > > foo x = doSomething x' > where x' | x == ... = ... > > or > > {-# LANGUAGE MultiWayIf #-} > > foo x = doSomething (if | x == ... -> ...) > Or simply in plain old Haskell (basically the desugaring of the multi-way-if): foo x = doSomething (case () of _ | x == gl_BAR -> expr1 | x == gl_BAZ -> expr2 | otherwise -> expr3) Compared to: foo x = doSomething (case x of GL_BAR -> expr1 GL_BAZ -> expr2 _ .> expr3) it doesn't really look *that* much different IMHO, given the high price one has to pay for a tiny improvement in readability. But that's my personal, more conservative view of things, and I'm here to see what other people prefer.Alas, up to now, this is not very conclusive... :-/

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Regal and cross platform 3D
by Jelle Hermsen 10 Jan '16

10 Jan '16

Hiya everybody, I’m planning to build a cross platform 3D application in Haskell and I’m thinking about using Regal (https://github.com/p3/regal ) as an abstraction layer so I can support OpenGL 2.x, 3.x, 4.x and ES 2.0 with the same code base. Has any of you have tried to use it with HopenGL / OpenGLRaw? Cheers, Jelle

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