public APIBuffer push() {
        if (stackDepth == stack.length) {
            stack = Arrays.copyOf(stack, stack.length << 1);
        }

        stack[stackDepth++] = offset;

        // Upward align the current offset to the pointer size.
        offset = (offset + (POINTER_SIZE - 1)) & -POINTER_SIZE;

        return this;
    }
Pushes the current parameter offset to a stack.
jme3-lwjgl3/src/main/java/com/jme3/lwjgl3/utils/APIBuffer.java