I put my thing down, flip it, and reverse it

src/main/java/io/github/cottonmc/templates/block/TemplateSlopeBlock.java

@@ -1,39 +1,49 @@
 package io.github.cottonmc.templates.block;
 
 import io.github.cottonmc.templates.Templates;
+import io.github.cottonmc.templates.util.StairShapeMaker;
 import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.ShapeContext;
 import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.block.enums.BlockHalf;
 import net.minecraft.item.ItemPlacementContext;
 import net.minecraft.state.StateManager;
 import net.minecraft.state.property.DirectionProperty;
+import net.minecraft.state.property.EnumProperty;
 import net.minecraft.state.property.Properties;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Direction;
 import net.minecraft.util.shape.VoxelShape;
-import net.minecraft.util.shape.VoxelShapes;
 import net.minecraft.world.BlockView;
 
 import javax.annotation.Nullable;
 
 public class TemplateSlopeBlock extends TemplateBlock {
 	public static final DirectionProperty FACING = Properties.HORIZONTAL_FACING;
+	public static final EnumProperty<BlockHalf> HALF = Properties.BLOCK_HALF;
 	
-	public static final VoxelShape BASE = VoxelShapes.cuboid(0f, 0f, 0f, 1f, 0.5f, 1f);
+	private static final VoxelShape[] shapes = new VoxelShape[8];
-	public static final VoxelShape NORTH = VoxelShapes.cuboid(0f, 0.5f, 0f, 1f, 1f, 0.5f);
+	private static int shapeIndex(Direction dir, BlockHalf half) {
-	public static final VoxelShape SOUTH = VoxelShapes.cuboid(0f, 0.5f, 0.5f, 1f, 1f, 1f);
+		return dir.getHorizontal() + (half == BlockHalf.TOP ? 4 : 0);
-	public static final VoxelShape EAST = VoxelShapes.cuboid(0.5f, 0.5f, 0f, 1f, 1f, 1f);
+	}
-	public static final VoxelShape WEST = VoxelShapes.cuboid(0f, 0.5f, 0f, 0.5f, 1f, 1f);
+	static {
+		for(BlockHalf half : BlockHalf.values()) {
+			for(Direction d : Direction.values()) {
+				if(d.getHorizontal() == -1) continue;
+				shapes[shapeIndex(d, half)] = StairShapeMaker.createHorizontal(d, half, 8, 0.125d, 0.125d);
+			}
+		}
+	}
 	
 	public TemplateSlopeBlock(Settings settings) {
 		super(settings);
-		setDefaultState(getDefaultState().with(FACING, Direction.NORTH));
+		setDefaultState(getDefaultState().with(FACING, Direction.NORTH).with(HALF, BlockHalf.BOTTOM));
 	}
 	
 	@Override
 	protected void appendProperties(StateManager.Builder<Block, BlockState> builder) {
-		super.appendProperties(builder.add(FACING));
+		super.appendProperties(builder.add(FACING, HALF));
 	}
 	
 	@Override
@@ -44,24 +54,20 @@ public class TemplateSlopeBlock extends TemplateBlock {
 	@Nullable
 	@Override
 	public BlockState getPlacementState(ItemPlacementContext ctx) {
-		return getDefaultState().with(FACING, ctx.getHorizontalPlayerFacing());
+		BlockHalf half = switch(ctx.getSide()) {
+			case UP -> BlockHalf.BOTTOM;
+			case DOWN -> BlockHalf.TOP;
+			default -> (ctx.getHitPos().getY() - (double) ctx.getBlockPos().getY() < 0.5) ? BlockHalf.BOTTOM : BlockHalf.TOP;
+		};
+		
+		return getDefaultState()
+			.with(FACING, ctx.getHorizontalPlayerFacing())
+			.with(HALF, half);
 	}
 	
 	@Override
 	public VoxelShape getCollisionShape(BlockState state, BlockView view, BlockPos pos, ShapeContext ctx) {
-		Direction dir = state.get(FACING);
+		return shapes[shapeIndex(state.get(FACING), state.get(HALF))];
-		switch(dir) {
-			case NORTH:
-				return VoxelShapes.union(BASE, NORTH);
-			case SOUTH:
-				return VoxelShapes.union(BASE, SOUTH);
-			case EAST:
-				return VoxelShapes.union(BASE, EAST);
-			case WEST:
-				return VoxelShapes.union(BASE, WEST);
-			default:
-				return VoxelShapes.fullCube();
-		}
 	}
 	
 	@Override

src/main/java/io/github/cottonmc/templates/util/StairShapeMaker.java

@@ -0,0 +1,64 @@
+package io.github.cottonmc.templates.util;
+
+import net.minecraft.block.enums.BlockHalf;
+import net.minecraft.util.math.Direction;
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.util.shape.VoxelShape;
+import net.minecraft.util.shape.VoxelShapes;
+
+public class StairShapeMaker {
+	public static VoxelShape createHorizontal(Direction shortSide, BlockHalf half, int steps, double rise, double run) {
+		VoxelShape shape = VoxelShapes.empty();
+		
+		Vec3d a, b, march;
+		switch(shortSide) {
+			case SOUTH -> {
+				a = new Vec3d(0, 0, 1);
+				b = new Vec3d(1, rise, 0);
+				march = new Vec3d(0, rise, run);
+			}
+			case NORTH -> {
+				a = new Vec3d(0, 0, 0);
+				b = new Vec3d(1, rise, 1);
+				march = new Vec3d(0, rise, -run);
+			}
+			case EAST -> {
+				a = new Vec3d(1, 0, 0);
+				b = new Vec3d(0, rise, 1);
+				march = new Vec3d(run, rise, 0);
+			}
+			case WEST -> {
+				a = new Vec3d(0, 0, 0);
+				b = new Vec3d(1, rise, 1);
+				march = new Vec3d(-run, rise, 0);
+			}
+			default -> {
+				return VoxelShapes.fullCube(); //TODO
+			}
+		}
+		
+		if(half == BlockHalf.TOP) {
+			a = new Vec3d(a.x, 1 - a.y, a.z);
+			b = new Vec3d(b.x, 1 - b.y, b.z);
+			march = march.multiply(1, -1, 1);
+		}
+		
+		for(int i = 0; i < steps; i++) {
+			VoxelShape newShape = agh(a.x, a.y, a.z, b.x, b.y, b.z);
+			shape = VoxelShapes.union(shape, newShape);
+			b = b.add(march);
+		}
+		
+		return shape.simplify();
+	}
+	
+	private static VoxelShape agh(double x1, double y1, double z1, double x2, double y2, double z2) {
+		double minX = Math.min(x1, x2);
+		double maxX = Math.max(x1, x2);
+		double minY = Math.min(y1, y2);
+		double maxY = Math.max(y1, y2);
+		double minZ = Math.min(z1, z2);
+		double maxZ = Math.max(z1, z2);
+		return VoxelShapes.cuboid(minX, minY, minZ, maxX, maxY, maxZ);
+	}
+}

src/main/resources/assets/templates/blockstates/slope.json

@@ -1,19 +1,38 @@
 {
 	"variants": {
-		"facing=east": {
+		"facing=east,half=bottom": {
 			"model": "templates:slope_special",
 			"y": 270
 		},
-		"facing=north": {
+		"facing=north,half=bottom": {
 			"model": "templates:slope_special",
 			"y": 180
 		},
-		"facing=south": {
+		"facing=south,half=bottom": {
 			"model": "templates:slope_special"
 		},
-		"facing=west": {
+		"facing=west,half=bottom": {
 			"model": "templates:slope_special",
 			"y": 90
+		},
+		"facing=east,half=top": {
+			"model": "templates:slope_special",
+			"x": 180,
+			"y": 90
+		},
+		"facing=north,half=top": {
+			"model": "templates:slope_special",
+			"x": 180
+		},
+		"facing=south,half=top": {
+			"model": "templates:slope_special",
+			"x": 180,
+			"y": 180
+		},
+		"facing=west,half=top": {
+			"model": "templates:slope_special",
+			"x": 180,
+			"y": 270
 		}
 	}
 }