Re: [osg-users] speed up the loading

2012-10-23 Thread Ulrich Hertlein 
Hi Shawl,

On 23/10/12 14:15, 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 quite sure which setVertexArray you are talking about, but the one in 
osg::Geometry is
simply a pointer assignment - nothing is copied or constructed.

/ulrich

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Re: [osg-users] speed up the loading

2012-10-23 Thread Jason Daly 
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_ptrVec3Array array = new Vec3Array(count/3, (Vec3 *) lotsOfPoints);

// Assign the Vec3Array to Geometry
ref_ptrGeometry geom = new Geometry();
geom-setVertexArray(array);

--J

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[osg-users] speed up the loading

2012-10-22 Thread wh_xiexing 

  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.

so i want to modified it to setVertexArray (float*)  , so that i can read a 
block of data from the disk and provide it to osg.   to do so.  the first thing 
is i must 

figure out how the osg interact with opengl.  unfortunately i see a lot of 
arraydispatcher which is complecated .   can someone tell me how can i do ?



Shawl___
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