Rotating Quad-Drawn Images - LWJGL

Img: http://b.1339.cf/vvllsst.png

//LoadingScreen.java
private void renderUnit(Unit u) {
    int a = (int) u.getAngle();
    int x = u.getX();
    int y = u.getY();
    int w = u.getWidth();
    int h = u.getHeight();
    GL11.glTranslated(w / 2, h / 2, 0);
    GL11.glRotated(a, 0, 0, 1);
    GL11.glTranslated(-w / 2, -h / 2, 0);
    GL11.glRotated(-a, 0, 0, 1);
    GL11.glTranslated(x, y, 0);
    GL11.glRotated(a, 0, 0, 1);
    GL11.glTranslated(-x, -y, 0);
    RenderUtil.renderTexture(x, y, w, h, u.getTextures().getAt(0));
}
//RenderUtil.java
public static void renderTexture(int x, int y, int width, int height, Texture texture) {
    GL11.glEnable(GL11.GL_TEXTURE_2D);
    GL11.glBindTexture(GL11.GL_TEXTURE_2D, texture.getTextureID());
    GL11.glBegin(GL11.GL_QUADS);
        GL11.glTexCoord2f(0, 0);
        GL11.glVertex2f(x, y);
        GL11.glTexCoord2f(0, 1);
        GL11.glVertex2f(x, y + height);
        GL11.glTexCoord2f(1, 1);
        GL11.glVertex2f(x + width, y + height);
        GL11.glTexCoord2f(1, 0);
        GL11.glVertex2f(x + width, y);
    GL11.glEnd();
}