Place blocks against actual hit face on non-full blocks

assets/cubyz/blocks/cloth/_defaults.zig.zon

@@ -7,5 +7,6 @@
 	.collide = false,
 	.model = "cubyz:carpet",
 	.rotation = "cubyz:carpet",
+	.placementMode = .gridNeighbor,
 	.degradable = true,
 }

assets/cubyz/blocks/daisies.zig.zon

@@ -12,6 +12,7 @@
 	.absorbedLight = 0x121012,
 	.model = "cubyz:plane",
 	.rotation = "cubyz:carpet",
+	.placementMode = .gridNeighbor,
 	.onUpdate = .{
 		.type = .check_support_blocks,
 	},

assets/cubyz/blocks/dandelions.zig.zon

@@ -12,6 +12,7 @@
 	.absorbedLight = 0x121012,
 	.model = "cubyz:plane",
 	.rotation = "cubyz:carpet",
+	.placementMode = .gridNeighbor,
 	.onUpdate = .{
 		.type = .check_support_blocks,
 	},

assets/cubyz/blocks/ivy.zig.zon

@@ -12,6 +12,7 @@
 	.absorbedLight = 0x121012,
 	.model = "cubyz:plane",
 	.rotation = "cubyz:carpet",
+	.placementMode = .gridNeighbor,
 	.texture = "cubyz:ivy",
 	.item = .{
 		.texture = "ivy.png",

assets/cubyz/blocks/osier.zig.zon

@@ -12,6 +12,7 @@
 	.absorbedLight = 0x121012,
 	.model = "cubyz:plane",
 	.rotation = "cubyz:carpet",
+	.placementMode = .gridNeighbor,
 	.onUpdate = .{
 		.type = .check_support_blocks,
 	},

src/blocks.zig

@@ -53,6 +53,11 @@ pub const Ore = struct {
 	seed: u64,
 };
 
+const PlacementMode = enum {
+	boundingBox,
+	gridNeighbor,
+};
+
 const SelectionCapabilities = union(enum) {
 	always: void,
 	custom: packed struct(u1) {
@@ -117,6 +122,7 @@ var _degradable: [maxBlockCount]bool = undefined;
 var _viewThrough: [maxBlockCount]bool = undefined;
 var _alwaysViewThrough: [maxBlockCount]bool = undefined;
 var _hasBackFace: [maxBlockCount]bool = undefined;
+var _placementMode: [maxBlockCount]PlacementMode = undefined;
 var _tags: [maxBlockCount][]Tag = undefined;
 var _light: [maxBlockCount]u32 = undefined;
 /// How much light this block absorbs if it is transparent
@@ -185,6 +191,7 @@ pub fn register(_: []const u8, id: []const u8, zon: ZonElement) u16 {
 	_alwaysViewThrough[size] = zon.get(bool, "alwaysViewThrough") orelse false;
 	_viewThrough[size] = (zon.get(bool, "viewThrough") orelse false) or _transparent[size] or _alwaysViewThrough[size];
 	_hasBackFace[size] = zon.get(bool, "hasBackFace") orelse false;
+	_placementMode[size] = zon.get(PlacementMode, "placementMode") orelse .boundingBox;
 	_friction[size] = zon.get(f32, "friction") orelse 20;
 	_bounciness[size] = zon.get(f32, "bounciness") orelse 0.0;
 	_density[size] = zon.get(f32, "density") orelse main.physics.airDensity;
@@ -478,6 +485,10 @@ pub const Block = packed struct(u32) { // MARK: Block
 		return _hasBackFace[self.typ];
 	}
 
+	pub inline fn placementMode(self: Block) PlacementMode {
+		return _placementMode[self.typ];
+	}
+
 	pub inline fn tags(self: Block) []const Tag {
 		return _tags[self.typ];
 	}

src/renderer.zig

@@ -993,6 +993,25 @@ pub const MeshSelection = struct { // MARK: MeshSelection
 		// TODO: Test entities
 	}
 
+	fn boundingBoxFaceNormal(relativePos: Vec3f, dir: Vec3f, min: Vec3f, max: Vec3f) ?Vec3i {
+		var tEnter: f32 = -std.math.inf(f32);
+		var result: ?Vec3i = null;
+		inline for (0..3) |axis| {
+			if (dir[axis] != 0) {
+				const t1 = (min[axis] - relativePos[axis])/dir[axis];
+				const t2 = (max[axis] - relativePos[axis])/dir[axis];
+				const t = @min(t1, t2);
+				if (t > tEnter) {
+					tEnter = t;
+					var normal: Vec3i = .{0, 0, 0};
+					normal[axis] = if (dir[axis] > 0) -1 else 1;
+					result = normal;
+				}
+			}
+		}
+		return if (tEnter >= 0) result else null;
+	}
+
 	fn canPlaceBlock(pos: Vec3i, block: main.blocks.Block) bool {
 		if (main.physics.collision.collideWithBlock(block, pos[0], pos[1], pos[2], main.game.Player.getPosBlocking() + main.game.Player.outerBoundingBox.center(), main.game.Player.outerBoundingBox.extent(), .{0, 0, 0}) != null) {
 			return false;
@@ -1025,14 +1044,17 @@ pub const MeshSelection = struct { // MARK: MeshSelection
 							}
 						}
 						// Check the block in front of it:
-						const neighborPos = posBeforeBlock;
-						neighborDir = selectedPos - posBeforeBlock;
+						const selectedRelPos: Vec3f = @floatCast(lastPos - @as(Vec3d, @floatFromInt(selectedPos)));
+						const boxFaceNormal: ?Vec3i = if (oldBlock.placementMode() == .boundingBox) boundingBoxFaceNormal(selectedRelPos, lastDir, selectionMin, selectionMax) else null;
+						const neighborPos = if (boxFaceNormal) |normal| selectedPos + normal else posBeforeBlock;
+						neighborDir = if (boxFaceNormal) |normal| -normal else selectedPos - posBeforeBlock;
+						const neighborOfSelectionValue = if (boxFaceNormal != null) chunk.Neighbor.fromRelPos(neighborDir).? else neighborOfSelection;
 						const relPos: Vec3f = @floatCast(lastPos - @as(Vec3d, @floatFromInt(neighborPos)));
 						const neighborBlock = block;
 						oldBlock = mesh_storage.getBlockFromRenderThread(neighborPos[0], neighborPos[1], neighborPos[2]) orelse return;
 						block = oldBlock;
 						if (block.typ == itemBlock) {
-							if (rotationMode.generateData(main.game.world.?, neighborPos, relPos, lastDir, neighborDir, neighborOfSelection, &block, neighborBlock, false)) {
+							if (rotationMode.generateData(main.game.world.?, neighborPos, relPos, lastDir, neighborDir, neighborOfSelectionValue, &block, neighborBlock, false)) {
 								if (!canPlaceBlock(neighborPos, block)) return;
 								updateBlockAndSendUpdate(inventory, slot, neighborPos, oldBlock, block);
 								return;
@@ -1041,7 +1063,7 @@ pub const MeshSelection = struct { // MARK: MeshSelection
 							if (!block.replaceable()) return;
 							block.typ = itemBlock;
 							block.data = 0;
-							if (rotationMode.generateData(main.game.world.?, neighborPos, relPos, lastDir, neighborDir, neighborOfSelection, &block, neighborBlock, true)) {
+							if (rotationMode.generateData(main.game.world.?, neighborPos, relPos, lastDir, neighborDir, neighborOfSelectionValue, &block, neighborBlock, true)) {
 								if (!canPlaceBlock(neighborPos, block)) return;
 								updateBlockAndSendUpdate(inventory, slot, neighborPos, oldBlock, block);
 								return;

src/rotation.zig

@@ -84,7 +84,7 @@ pub const RotationMode = struct { // MARK: RotationMode
 			}
 			if (minimum != null) {
 				// Invert the normal if the player is behind the face (eg. cross model)
-				if (vec.dot(normal.?, relativePlayerPos) < 0.0) {
+				if (vec.dot(normal.?, playerDir) > 0.0) {
 					normal = -normal.?;
 				}
 				return .{