Problems with direct buffers and vertex arrays.

OpenGL Development JOGL Development
#1

For some reason when I use a direct momory buffer with the following code nothing is drawn. The thing works just fine with a simple float[] array. Can someone see what i’m doing wrong?

public void display(GLDrawable drawable) {
final int num = 4;
final int data_len = 6;
final float[] intertwined = new float[] {
1.0f, 0.2f, 1.0f, -1.0f, -1.0f, 0.0f,
1.0f, 0.2f, 0.2f, 1.0f, -1.0f, 0.0f,
1.0f, 1.0f, 0.2f, 1.0f, 1.0f, 0.0f,
0.2f, 1.0f, 0.2f, -1.0f, 1.0f, 0.0f};

FloatBuffer direct = ByteBuffer.allocateDirect(
numdata_lenBufferUtils.SIZEOF_FLOAT).asFloatBuffer();
direct.put(intertwined);
direct.flip();
context.gl.glInterleavedArrays(GL.GL_C3F_V3F, 0, direct);

context.gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);

context.gl.glLoadIdentity();
context.gl.glTranslatef(-1.5f, 0, -7);

context.gl.glBegin(GL.GL_QUADS);
context.gl.glArrayElement(0); 
context.gl.glArrayElement(1); 
context.gl.glArrayElement(2); 
context.gl.glArrayElement(3); 
context.gl.glEnd();

}

10x in advance.

#2

Opsss…forgot to remove the “context.” from all GL calls.
Read that as “drawable.getGL().” instead :wink:

#3

The byte order of your ByteBuffer wasn’t set to native order. The BufferUtils class in net.java.games.jogl.util handles this for you and is the recommended way of allocating direct buffers for use with JOGL.

#4

10x. This indeed was the problem :slight_smile: