On 10/22/2012 11:15 PM, wh_xiexing wrote:
> i have hundreds of millions of points to render. i think the Geometry
> 's setVertexArray (Vec3Array) is time consuming .
> for every point , it must construct a Vec3 class, and put it into the
> array.
Not true, you can create a Vec3Array out of an array of floats with
nothing but a type cast. The Vec* and Vec*Array classes were designed to
line up data contiguously in memory so that OpenGL could use it directly
and efficiently (note that there are no virtual methods in the Vec*
classes).
There's no reason to modify OSG to do what you want:
// Construct an array of floats
float * lotsOfPoints = new float[count];
// Fill up the float array with point data
...
// Construct a Vec3Array out of the float data
ref_ptr array = new Vec3Array(count/3, (Vec3 *) lotsOfPoints);
// Assign the Vec3Array to Geometry
ref_ptr geom = new Geometry();
geom->setVertexArray(array);
--"J"
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