How to dynamically update a texture?

[nathanielvirgo]

I'm not sure if this is the place to post "how do I..." type questions, but I wasn't able to find any kind of user forum, so please point me onwards if I'm in the wrong place.

I'm hoping I can use this package for the relatively simple task of displaying a simple 2D grid-based simulation in real time as it updates. I'd like to use OpenGL for this because then the display won't slow it down too much and I can easily zoom and pan around etc. To do this, I need to either dynamically update a texture, or create a new one each frame.

Starting with the tutorial at https://github.com/JuliaGL/GLAbstraction.jl/blob/master/tutorials/textures1.jl, I tried creating a new Texture object and calling std_renderobject again on each iteration. This works, but it seems quite slow, and makes me wonder if this is the right way to do it. However, I was unable to find any documentation suggesting whether these objects can be dynamically updated without creating new ones every time.

My apologies if this is a dumb question. I'm not at all an OpenGL expert, and would greatly appreciate a simple explanation or even just an example of the best way to dynamically update a texture (from a cpu-based Julia array), if that can be done in this package.

[SimonDanisch]

You should be able to use GLAbstraction.update!(tex, newdata), or even tex[:, :] = newdata. Let me know if it works!

[nathanielvirgo]

Great, the first option works, and is fast.

The second one fails with this message:

ERROR: LoadError: Indexing only defined for integers or ranges. Found: Colon()
Stacktrace:
[1] (::GLAbstraction.##1#2)(::Colon) at /Users/ndv/.julia/v0.6/GLAbstraction/src/AbstractGPUArray.jl:52
[2] setindex!(::GLAbstraction.Texture{ColorTypes.RGBA{FixedPointNumbers.Normed{UInt8,8}},2}, ::Array{ColorTypes.RGBA{FixedPointNumbers.Normed{UInt8,8}},2}, ::Colon, ::Colon) at /Users/ndv/.julia/v0.6/GLAbstraction/src/AbstractGPUArray.jl:58
[3] macro expansion at /Users/ndv/Dropbox/Code/Julia GL testing/test04.jl:53 [inlined]
[4] anonymous at ./:?
[5] include_from_node1(::String) at ./loading.jl:576
[6] include(::String) at ./sysimg.jl:14
[7] process_options(::Base.JLOptions) at ./client.jl:305
[8] _start() at ./client.jl:371
while loading /Users/ndv/Dropbox/Code/Julia GL testing/test04.jl, in expression starting on line 46

(Let me know if you need the code I'm running. But I'm happy now, since I have a method that works!)