Re: How to access following data using Luabind

Hello, 

Thanks for your help.

I was able to make it work, though I have 1 problem:

This is my Placemark (trapezoid) C++ Class constructor:

Placemark::Placemark(float x1, float y1,
		     float x2, float y2,
		     float x3, float y3,
		     float x4, float y4)
{ 
	vertex[0] = Vec2f(x1, y1);
	vertex[1] = Vec2f(x2, y2);
	vertex[2] = Vec2f(x3, y3);
	vertex[3] = Vec2f(x4, y4);
	
	//Create the vertex Dots
	for(int i = 0; i < 4; ++i)
	{
		VertexCircle *c = new VertexCircle(vertex[i], i);
		c->setParent(this);
		vertexDots.push_back(c);
	}
	
	glGenBuffers(1, &vbo);
}

However I bounded this constructor using luabind and called it in Lua with:

	p = Placemark(1.0, 2.0, 3.0, 4.0, 1.0, 2.0, 3.0, 4.0)

The following piece of code in my C++ constructor:

	glGenBuffers(1, &vbo); //vbo is a Placemark private attribute. GLuint vbo;

Makes my Application to Crash.

I don't really know why, and it's easy to take that line out from my constructor, but still I was wondering if someone could enlighten me about why is it crashing when calling the OpenGL function glGenBuffers ??

Thanks.

--------------------------------------------------------------
Nicolas Goles Domic
Founder & Lead Programmer of Gando Games





On Jun 18, 2010, at 4:42 AM, Iliya Trendafilov wrote:

> Hi,
> 
> Just to access the data from your script in C++ you can do something like this:
> 
> luabind::object_cast<double>(luabind::globals(lua)["polygons"]["vertex"][1][1])
> // returns x1 of the first trapezoid
> 
> The return of every operator[] above is luabind::object that you could "cache".
> 
> That said, I'd rather register Color3f and Trapezoid classes with at
> least their constructors, then write a tiny glue lua script
> 
> polygonInsances = {}
> for i = 1, #polygons.vertex
> do
>    local v = polygons.vertex[i]
>    local c = polygons.color[i]
>    polygonInstances[i] = Trapezoid(v[1][1], v[1][2], v[2][1],
> v[2][2], v[3][1], v[3][2], v[4][1], v[4][2], Color3f(c[1], c[2],
> c[3]))
> done
> 
> And then use polygonInstances:
> 
> luabind::object_cast<Trapezoid>(luabind::globals(lua)["polygonInstances"][1]);
> // returns the first trapezoid
> 
> Hope that helps.
> (WARNING: None of the code above has been compiled or run through Lua
> interpreter)
> 
> 
> 
> On Fri, Jun 18, 2010 at 8:54 AM, Nicolas Goles <[email protected]> wrote:
>> Hello,
>> I'm quite new to Luabind, I'm trying to access the following data
>> polygons = {
>> -- 3 "different" Trapezoidal polygons, 4 vertex (x,y) each.
>> vertex = {
>> {{1,0}, {1,10}, {21,30}, {25,35}},
>> {{1,0}, {1,10}, {21,30}, {25,35}},
>> {{1,0}, {1,10}, {21,30}, {25,35}},
>> },
>> -- 3 Colors ( R , G , B) one for each polygon
>> color = {
>> {1,0,0},
>> {0,1,0},
>> {0,0,1},
>> }
>> }
>> it represents 3 "different" trapezoidal polygons, each one with a color.
>> In my Application, I have a C++ class "Trapezoid" that has a constructor
>> that receives 8 floats (x1,y2 , x2, y2.... ) and a color.
>> Trapezoid::Trapezoid(x1, y1, x2, y2, x3, y3, x4, y4, Color3f color);
>> What would be the correct way to access this Lua script using luabind? I
>> have been struggling all day.
>> Sorry if this is noobish, but haven't found any clear solutions for this (
>> most of the examples focus on executing functions, and more complex stuff )
>> What would you guys suggest  ?
>> Thanks!
>> _Nicolas
>> ------------------------------------------------------------------------------
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>> 
>> 
> 
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> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the 
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