I'm using LuaGL in the code below and want to monitor calls to the gl
table because I need to check if there is a valid OpenGL context
before letting the function call proceed. Surprisingly (to me at
least), the code below doesn't work properly. Calls like gl.Color(1.,
1., 0., 1.) work as expected, but calls like gl.Begin("LINES") produce
a "indexing a function value" error. Given the code below, why would
this happen? It doesn't make any sense to me at all.
Also note that this.context is a globally accessible variable. If you
have LuaGL and want to test this code, just take that part out.
___gl = gl
gl_temp_meta = {}
gl_temp_meta.__index = function(t, k)
if(this.context ~= 0) then
return function(...)
local args = {...}
print("\nargs")
for k, v in pairs(args) do
print(v)
end
return ___gl[k](...)
end
else
return function()
print("No valid OpenGL context")
end
end
end
gl_temp = {}
setmetatable(gl_temp, gl_temp_meta)
gl = gl_temp
function draw()
local C = gl.Color
local B = gl.Begin
print("C: " .. tostring(C))
print("B: " .. tostring(B))
gl.Color(1., 1., 0., 1.)
gl.Begin("LINES")
gl.Vertex(-1., 0., 0.)
gl.Vertex(1., 0., 0.)
gl.End()
end
thanks,
wes
