Problem Drawing a wireframe with VBO

[elantzb]

I just recently got my feet wet with OpenGL, and I'm having an issue with drawing a wireframe with a vertex array. Drawing a quad works just fine, but when I use GL_LINE_LOOP, a fifth vertex (which I believe is at 0,0,0) appears:



I'm sure the problem is a novice mistake.

import java.nio.FloatBuffer;

import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.*;


public class VectorArrayTest 
{
	FloatBuffer vertBuff;
	int vertArrayID;
	int vertBufferID;
	int numVerts;

	public VectorArrayTest()
	{
		try 
		{
			Display.setDisplayMode(new DisplayMode(300,200));
			Display.create();
		} 
		catch (LWJGLException e) 
		{
			e.printStackTrace();
		}
		
		initOpenGL();
		initData();
		
		while(!Display.isCloseRequested())
		{
			doCycle();
			
			Display.update();
		}
		
		onExit();
	}
	
	public void initOpenGL()
	{
GL11.glEnableClientState(GL11.GL_VERTEX_ARRAY);
		GL11.glMatrixMode(GL11.GL_PROJECTION);
		GL11.glLoadIdentity();
		GL11.glOrtho(-1, 1.0, -1, 1.0, 0.1, 3.0);
		GL11.glMatrixMode(GL11.GL_MODELVIEW);
		GL11.glTranslatef(0.0f,0.0f,-0.5f);
		
		GL11.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	}
	
	public void initData()
	{
		float[] verts = { 
				0.75f, 0.75f, -0.9f,
				0.25f, 0.75f, -0.9f,
				0.25f, 0.25f, -0.9f,
				0.75f, 0.25f, -0.9f };
		
		vertBuff = org.lwjgl.BufferUtils.createFloatBuffer(verts.length);
		vertBuff.put(verts);
		vertBuff.flip();
		
		numVerts = verts.length;
		
		vertArrayID = GL30.glGenVertexArrays();
		vertBufferID = GL15.glGenBuffers();
	}
	
	public void doCycle()
	{
		GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
				
		GL11.glColor3d(1.0, 1.0, 1.0);
		
		
		GL30.glBindVertexArray(vertArrayID);
		GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vertArrayID);
		GL15.glBufferData(GL15.GL_ARRAY_BUFFER, vertBuff, GL15.GL_STATIC_DRAW);
		
		GL20.glVertexAttribPointer(0, 3, GL11.GL_FLOAT, false, 0, 0);
		
		GL20.glEnableVertexAttribArray(0);
		
		GL11.glDrawArrays(GL11.GL_LINE_LOOP, 0, numVerts);
		
		GL20.glDisableVertexAttribArray(0);
		GL30.glBindVertexArray(0);
		
		GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
		GL15.glDeleteBuffers(vertBufferID);
		GL30.glBindVertexArray(0);
		GL30.glDeleteVertexArrays(vertArrayID);
	}
	
	public void onExit()
	{
		GL11.glDisableClientState(GL11.GL_VERTEX_ARRAY);
	}
	
	public static void main(String[] args)
	{
		new VectorArrayTest();
	}
}

[elantzb]

FIXED: My numVerts variable was way too big.


numVerts = verts.length;
numVerts = verts.length/3;