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Index › Programming Questions & Help › OpenGL and 3D Libraries › GLModel Vertices Coordinates
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GLModel Vertices Coordinates (Read 974 times)
sdh
GLModel Vertices Coordinates
Dec 22nd, 2009, 10:32am  
Hey,
I'm quite new to the OpenGL Stuff, so this might be a very easy question:

I'm using the GLGraphics Library. In my code i created some VBOs via GLModel. I wondered if there is a quick method or function to get the Coordinates of the Vertices I created?

Thanks!
Chris
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ac
Re: GLModel Vertices Coordinates
Reply #1 - Jan 3rd, 2010, 10:48pm  
From the time you call GLModel.beginUpdateVertices() until you do GLModel.endUpdateVertices(), all the vertex coordinates are accessible through GLModel.vertices, which is a java FloatBuffer. Example:

Code:

float[] vertArray = new float[4 * model.getSize()];
model.beginUpdateVertices();
model.vertices.get(vertArray); // Copy coordinates to float array.

// Do some operation on the vertices (scaling in this case):
for (int i = 0; i < model.getSize(); i++) {
  vertArray[4 * i + 0] *= 2;  // X coordinate of vertex i.
  vertArray[4 * i + 1] *= 2;  // Y coordinate of vertex i.
  vertArray[4 * i + 2] *= 2;  // Z coordinate of vertex i.
}

model.vertices.put(vertArray); // Copy float array back to model.

model.endUpdateVertices();
// model.vertices cannot be accessed after
// beginUpdateVertices()/endUpdateVertices()

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sdh
Re: GLModel Vertices Coordinates
Reply #2 - Jan 6th, 2010, 2:42pm  
Great!

This helps alot!

Chris.
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ac
Re: GLModel Vertices Coordinates
Reply #3 - Jan 6th, 2010, 4:06pm  
You are welcome. One small detail though. I mentioned the method model.getSize() in the code snipped in my previous post. I added it recently, but is not available yet in the version you can download from sourceforge. So just replace model.getSize() by the number of vertices you specified in the constructor.
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