world: replay datapack features across regions

internal/world/underwater_magma_test.go

@@ -0,0 +1,73 @@
+package world
+
+import (
+	"testing"
+
+	"regionio/internal/worldgen"
+)
+
+func TestUnderwaterFloorMatchesColumnScanRange(t *testing.T) {
+	chunk := NewChunk(0, 0, BiomePlains)
+	region, err := newDecorationRegion([]*Chunk{chunk})
+	if err != nil {
+		t.Fatal(err)
+	}
+	for y := 7; y <= 10; y++ {
+		chunk.SetBlock(3, y, 4, StateWater)
+	}
+	chunk.SetBlock(3, 6, 4, StateStone)
+	if floor, ok := region.underwaterFloor(3, 10, 4, 5); !ok || floor != 6 {
+		t.Fatalf("floor = %d, %v; want 6, true", floor, ok)
+	}
+	if _, ok := region.underwaterFloor(3, 10, 4, 4); ok {
+		t.Fatal("floor outside Column.scan range was accepted")
+	}
+}
+
+func TestUnderwaterMagmaPlacementIsDeterministic(t *testing.T) {
+	makeRegion := func() *decorationRegion {
+		chunk := NewChunk(0, 0, BiomePlains)
+		for x := 6; x <= 10; x++ {
+			for z := 6; z <= 10; z++ {
+				for y := 0; y <= 5; y++ {
+					chunk.SetBlock(x, y, z, StateStone)
+				}
+				for y := 6; y <= 10; y++ {
+					chunk.SetBlock(x, y, z, StateWater)
+				}
+			}
+		}
+		region, err := newDecorationRegion([]*Chunk{chunk})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := region.setSource(0, 0); err != nil {
+			t.Fatal(err)
+		}
+		return region
+	}
+	config := worldgen.UnderwaterMagmaFeatureConfig{
+		FloorSearchRange: 6, PlacementProbability: 1, PlacementRadiusAroundFloor: 1,
+	}
+	magma, ok := nameToStateID("minecraft:magma_block", nil)
+	if !ok {
+		t.Fatal("magma block state missing")
+	}
+	a, b := makeRegion(), makeRegion()
+	origin := worldgen.FeaturePosition{X: 8, Y: 10, Z: 8}
+	if !a.placeUnderwaterMagma(worldgen.NewWorldgenRandom(42), origin, config, magma) {
+		t.Fatal("magma placement changed no blocks")
+	}
+	if !b.placeUnderwaterMagma(worldgen.NewWorldgenRandom(42), origin, config, magma) {
+		t.Fatal("second magma placement changed no blocks")
+	}
+	for x := 6; x <= 10; x++ {
+		for z := 6; z <= 10; z++ {
+			for y := 0; y <= 10; y++ {
+				if a.getBlock(x, y, z) != b.getBlock(x, y, z) {
+					t.Fatalf("placements differ at (%d,%d,%d)", x, y, z)
+				}
+			}
+		}
+	}
+}