VertexArray.java

package game.graphics;

import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL20.*;
import static org.lwjgl.opengl.GL30.*;

import game.utils.BufferUtils;

public class VertexArray {
	
	private int vao, vbo, ibo, tbo;
	private int numVertices;
	
	public VertexArray(int numVertices) {
		this.numVertices = numVertices;
		vao = glGenVertexArrays();
	}
	
	public VertexArray(float[] vertices, byte[] indices, float[] textureCoords) {
		numVertices = indices.length;
		
		vao = glGenVertexArrays();
		glBindVertexArray(vao);
		
		// Note: pointerOffset parameters must be zero
		vbo = glGenBuffers();
		glBindBuffer(GL_ARRAY_BUFFER, vbo);
		glBufferData(GL_ARRAY_BUFFER, BufferUtils.createFloatBuffer(vertices), GL_STATIC_DRAW);
		glVertexAttribPointer(Shader.VERTEX_ATTRIB, 3, GL_FLOAT, false, 0, 0);
		glEnableVertexAttribArray(Shader.VERTEX_ATTRIB);

		tbo = glGenBuffers();
		glBindBuffer(GL_ARRAY_BUFFER, tbo);
		glBufferData(GL_ARRAY_BUFFER, BufferUtils.createFloatBuffer(textureCoords), GL_STATIC_DRAW);
		glVertexAttribPointer(Shader.TCOORD_ATTRIB, 2, GL_FLOAT, false, 0, 0);
		glEnableVertexAttribArray(Shader.TCOORD_ATTRIB);
		
		ibo = glGenBuffers();
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
		glBufferData(GL_ELEMENT_ARRAY_BUFFER, BufferUtils.createByteBuffer(indices), GL_STATIC_DRAW);
		
		glBindBuffer(GL_ARRAY_BUFFER, 0);
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
		glBindVertexArray(0); // Unbind when done
	}
	
	public void bind() {
		glBindVertexArray(vao);
		if (ibo > 0) {
			glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
		}
	}
	
	public void unbind() {
		if (ibo > 0) {
			glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
		}
		glBindVertexArray(0);
	}
	
	public void draw() {
		if (ibo > 0) {
			glDrawElements(GL_TRIANGLES, numVertices, GL_UNSIGNED_BYTE, 0);
		} else {
			glDrawArrays(GL_TRIANGLES, 0, numVertices);
		}
	}
	
	public void render() {
		bind();
		draw();
	}
	
}