slab variants

1 files changed, 66 insertions, 4 deletions

diff --git a/server/block_def.go b/server/block_def.go
index a5adb40..cbd4596 100644
--- a/server/block_def.go
+++ b/server/block_def.go
@@ -70,15 +70,36 @@ type blockDef struct {
 }
 
 type rotateVariant int
+type slabMaterial struct{}
+type slabVariant bool
+
+func markVariants(variants map[any]blockType) {
+	for _, block := range variants {
+		def := blockDefinitions[block]
+		if def.Variants == nil {
+			def.Variants = make(map[any]blockType)
+			blockDefinitions[block] = def
+		}
+		for variation, block := range variants {
+			def.Variants[variation] = block
+		}
+	}
+}
+
+func assertNoDef(block blockType) {
+	if _, ok := blockDefinitions[block]; ok {
+		panic("variant would override existing block")
+	}
+}
 
 var rotationNames = []string {"-N", "-E", "-S", "-W"}
 func makeRotations(block blockType) {
-	var variants = make(map[any]blockType)
 	oldDef := blockDefinitions[block]
+	variants := make(map[any]blockType)
 	for i := 0; i < 4; i++ {
 		newBlock := block + blockType(i)
-		if _, ok := blockDefinitions[newBlock]; i != 0 && ok {
-			panic("variant would override existing block")
+		if i != 0 {
+			assertNoDef(newBlock)
 		}
 		newDef := oldDef
 		for j := 0; j < 4; j++ {
@@ -106,9 +127,50 @@ func makeRotations(block blockType) {
 		newDef.Min = [3]byte {byte(minX), oldDef.Min[1], byte(minZ)}
 		newDef.Max = [3]byte {byte(maxX), oldDef.Max[1], byte(maxZ)}
 		newDef.Name = newDef.Name + rotationNames[i]
-		newDef.Variants = variants
+		variants[rotateVariant(i)] = newBlock
 		blockDefinitions[newBlock] = newDef
 	}
+	markVariants(variants)
+}
+
+func makeSlabs(material blockType, slab blockType, name string) {
+	materialDef := blockDefinitions[material]
+	variants := make(map[any]blockType)
+	variants[slabMaterial{}] = material
+
+	if name == "" {
+		name = materialDef.Name + " Slab"
+	}
+
+	bottomSlab := materialDef
+	bottomSlab.Name = name + "-D"
+	bottomSlab.Shape = cuboidShape
+	bottomSlab.Min = [3]byte {0, 0, 0}
+	bottomSlab.Max = [3]byte {16, 8, 16}
+	switch material {
+	default:
+		assertNoDef(slab)
+		variants[slabVariant(false)] = slab
+		blockDefinitions[slab] = bottomSlab
+	case blockDoubleSlab:
+		variants[slabVariant(false)] = blockSlab
+		blockDefinitions[blockSlab] = bottomSlab
+		slab--
+	case blockCobblestone:
+		variants[slabVariant(false)] = blockCobblestoneSlab
+		blockDefinitions[blockCobblestoneSlab] = bottomSlab
+		slab--
+	}
+	topSlab := materialDef
+	topSlab.Name = name + "-U"
+	topSlab.Shape = cuboidShape
+	topSlab.Min = [3]byte {0, 8, 0}
+	topSlab.Max = [3]byte {16, 16, 16}
+	assertNoDef(slab + 1)
+	variants[slabVariant(true)] = slab + 1
+	blockDefinitions[slab + 1] = topSlab
+
+	markVariants(variants)
 }
 
 func getBlockDefPackets() iter.Seq[classic.Packet] {