GLua was especially designed as a base library for the Demoniak3D real-time engine, as it provides a consistent framework with GLSL shaders. ]]> http://projets.ch/wp/blog/43/feed/ 0 http://projets.ch/wp/blog/10/ http://projets.ch/wp/blog/10/#comments Thu, 20 Mar 2008 16:10:52 +0000 Philippe Guglielmetti http://projets.ch/wp/blog/2008/03/20/librairie-glua/ Contents:

• vec3.lua : 3D vectors and arithmetic
• mat3.lua : 3D matrix and arithmetic
• vec4.lua : 4D vectors and arithmetic
• glsl.lua : generic functions following glsl prototypes as defined in book “OpenGL Shading Language” by Randi J. Rost
• test.X.lua : unit test of module X

Usage & Samples:

Usage of the classes and functions is pretty straightforward.

Check the test.X.lua modules for more details or examples

Download:

GLua is available on http://luaforge.net/projects/glua/ under LGPL licence.

Implementation details:

• the classes are based on class.lua, described on http://lua-users.org/wiki/SimpleLuaClasses
• glsl.lua offers generic function that work on LUA numbers and tables, and therefore all vector / matrix classes. It makes extensive use of functional programming to achieve this:
  • the “apply” function is defined as follows:
    --- applies a function to a table of parameters
-- @param f : function to apply to each element in v
-- @param v : (vector of) parameter(s) to f function
-- @return : (vector of) result(s) of f(v)
function apply(f,v)
if type(v)=="number" then return f(v) end
if type(v)=="table" then
local res={}
for i,x in ipairs(v) do res[i]=f(x) end
return res
end
error("apply "..f.."("..type(v)..") not implemented")
end
  • then, functions can easily be defined to support numbers, vectors, or matrices:
function sin(rad)
return apply(math.sin,rad)
end
• dot product is implemented in 2 different ways :
  • through the “power” ^ operator in classes
  • as a generic dot(p1,p2) function in glsl.lua