// prevent moused over blocks being outlined in the usual way (ie. by raytracing from player to block)
    @SubscribeEvent
    public static void onHighlightBlockEvent(DrawSelectionEvent.HighlightBlock evt) {
        if (MC.level != null) {
            drawSelectionBox(evt.getMatrix());
            evt.setCanceled(true);
        }
    }

    static BlockPos testBlockPos = new BlockPos(346,64,-273);

    public static void drawSelectionBox(PoseStack matrix)
    {
        Entity camEntity = MC.getCameraEntity();
        BlockPos blockpos = testBlockPos;
        BlockState blockstate = MC.level.getBlockState(blockpos);
        double d0 = camEntity.getX();
        double d1 = camEntity.getY() + camEntity.getEyeHeight();
        double d2 = camEntity.getZ();

        if (!blockstate.isAir()) {
            VertexConsumer vertexConsumer = MC.renderBuffers().bufferSource().getBuffer(RenderType.lines());

            final double xIn = (double) blockpos.getX() - d0;
            final double yIn = (double) blockpos.getY() - d1;
            final double zIn = (double) blockpos.getZ() - d2;

            VoxelShape shapeIn = blockstate.getShape(MC.level, blockpos); // need to put back in ISelectionThingo?
            Matrix4f matrix4f = matrix.last().pose();

            shapeIn.forAllEdges((x0, y0, z0, x1, y1, z1) ->
            {
                vertexConsumer.vertex(matrix4f, (float) (x0 + xIn), (float) (y0 + yIn), (float) (z0 + zIn)).color(1.0f,1.0f,1.0f,1.0f).endVertex();
                vertexConsumer.vertex(matrix4f, (float) (x1 + xIn), (float) (y1 + yIn), (float) (z1 + zIn)).color(1.0f,1.0f,1.0f,1.0f).endVertex();
            });
        }
    }