public SpriteBatch (int size, ShaderProgram defaultShader) {
		// 32767 is max vertex index, so 32767 / 4 vertices per sprite = 8191 sprites max.
		if (size > 8191) throw new IllegalArgumentException("Can't have more than 8191 sprites per batch: " + size);

		VertexDataType vertexDataType = (Gdx.gl30 != null) ? VertexDataType.VertexBufferObjectWithVAO : defaultVertexDataType;

		mesh = new Mesh(vertexDataType, false, size * 4, size * 6,
			new VertexAttribute(Usage.Position, 2, ShaderProgram.POSITION_ATTRIBUTE),
			new VertexAttribute(Usage.ColorPacked, 4, ShaderProgram.COLOR_ATTRIBUTE),
			new VertexAttribute(Usage.TextureCoordinates, 2, ShaderProgram.TEXCOORD_ATTRIBUTE + "0"));

		projectionMatrix.setToOrtho2D(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());

		vertices = new float[size * Sprite.SPRITE_SIZE];

		int len = size * 6;
		short[] indices = new short[len];
		short j = 0;
		for (int i = 0; i < len; i += 6, j += 4) {
			indices[i] = j;
			indices[i + 1] = (short)(j + 1);
			indices[i + 2] = (short)(j + 2);
			indices[i + 3] = (short)(j + 2);
			indices[i + 4] = (short)(j + 3);
			indices[i + 5] = j;
		}
		mesh.setIndices(indices);

		if (defaultShader == null) {
			shader = createDefaultShader();
			ownsShader = true;
		} else
			shader = defaultShader;
	}

	/** Returns a new instance of the default shader used by SpriteBatch for GL2 when no shader is specified. */
	static public ShaderProgram createDefaultShader () {
		String vertexShader = "attribute vec4 " + ShaderProgram.POSITION_ATTRIBUTE + ";\n" //
			+ "attribute vec4 " + ShaderProgram.COLOR_ATTRIBUTE + ";\n" //
			+ "attribute vec2 " + ShaderProgram.TEXCOORD_ATTRIBUTE + "0;\n" //
			+ "uniform mat4 u_projTrans;\n" //
			+ "varying vec4 v_color;\n" //
			+ "varying vec2 v_texCoords;\n" //
			+ "\n" //
			+ "void main()\n" //
			+ "{\n" //
			+ "   v_color = " + ShaderProgram.COLOR_ATTRIBUTE + ";\n" //
			+ "   v_color.a = v_color.a * (255.0/254.0);\n" //
			+ "   v_texCoords = " + ShaderProgram.TEXCOORD_ATTRIBUTE + "0;\n" //
			+ "   gl_Position =  u_projTrans * " + ShaderProgram.POSITION_ATTRIBUTE + ";\n" //
			+ "}\n";
		String fragmentShader = "#ifdef GL_ES\n" //
			+ "#define LOWP lowp\n" //
			+ "precision mediump float;\n" //
			+ "#else\n" //
			+ "#define LOWP \n" //
			+ "#endif\n" //
			+ "varying LOWP vec4 v_color;\n" //
			+ "varying vec2 v_texCoords;\n" //
			+ "uniform sampler2D u_texture;\n" //
			+ "void main()\n"//
			+ "{\n" //
			+ "  gl_FragColor = v_color * texture2D(u_texture, v_texCoords);\n" //
			+ "}";

		ShaderProgram shader = new ShaderProgram(vertexShader, fragmentShader);
		if (!shader.isCompiled()) throw new IllegalArgumentException("Error compiling shader: " + shader.getLog());
		return shader;
	}