New weather condition fixing code.minecraft-1.7

Fixing the weather conditions is now based on a snow line, i.e. the
highest Y value that can have snow naturally. That way we can simulate
the snow/ice placement of Minecraft 1.7.

2 files changed, 83 insertions, 86 deletions

diff --git a/biome_infos.go b/biome_infos.go
index 8e42b47..c45294c 100644
--- a/biome_infos.go
+++ b/biome_infos.go
@@ -137,69 +137,70 @@ var bioColors = map[mcmap.Biome]*gdk.Color{
 	mcmap.BioUncalculated:         gdk.NewColor("#333333"),
 }
 
-// TODO: Minecraft 1.7 will let it snow in some medium-cold biomes, depending on the height. We should simulate that.
-var coldBiome = map[mcmap.Biome]bool{
-	mcmap.BioOcean:                false,
-	mcmap.BioPlains:               false,
-	mcmap.BioDesert:               false,
-	mcmap.BioExtremeHills:         false,
-	mcmap.BioForest:               false,
-	mcmap.BioTaiga:                false,
-	mcmap.BioSwampland:            false,
-	mcmap.BioRiver:                false,
-	mcmap.BioHell:                 false,
-	mcmap.BioSky:                  false,
-	mcmap.BioFrozenOcean:          true,
-	mcmap.BioFrozenRiver:          true,
-	mcmap.BioIcePlains:            true,
-	mcmap.BioIceMountains:         true,
-	mcmap.BioMushroomIsland:       false,
-	mcmap.BioMushroomIslandShore:  false,
-	mcmap.BioBeach:                false,
-	mcmap.BioDesertHills:          false,
-	mcmap.BioForestHills:          false,
-	mcmap.BioTaigaHills:           true,
-	mcmap.BioExtremeHillsEdge:     false,
-	mcmap.BioJungle:               false,
-	mcmap.BioJungleHills:          false,
-	mcmap.BioJungleEdge:           false,
-	mcmap.BioDeepOcean:            false,
-	mcmap.BioStoneBeach:           false,
-	mcmap.BioColdBeach:            true,
-	mcmap.BioBirchForest:          false,
-	mcmap.BioBirchForestHills:     false,
-	mcmap.BioRoofedForest:         false,
-	mcmap.BioColdTaiga:            true,
-	mcmap.BioColdTaigaHills:       true,
-	mcmap.BioMegaTaiga:            false,
-	mcmap.BioMegaTaigaHills:       false,
-	mcmap.BioExtremeHillsPlus:     false,
-	mcmap.BioSavanna:              false,
-	mcmap.BioSavannaPlateau:       false,
-	mcmap.BioMesa:                 false,
-	mcmap.BioMesaPlateauF:         false,
-	mcmap.BioMesaPlateau:          false,
-	mcmap.BioSunflowerPlains:      false,
-	mcmap.BioDesertM:              false,
-	mcmap.BioExtremeHillsM:        false,
-	mcmap.BioFlowerForest:         false,
-	mcmap.BioTaigaM:               false,
-	mcmap.BioSwamplandM:           false,
-	mcmap.BioIcePlainsSpikes:      true,
-	mcmap.BioIceMountainsSpikes:   true,
-	mcmap.BioJungleM:              false,
-	mcmap.BioJungleEdgeM:          false,
-	mcmap.BioBirchForestM:         false,
-	mcmap.BioBirchForestHillsM:    false,
-	mcmap.BioRoofedForestM:        false,
-	mcmap.BioColdTaigaM:           true,
-	mcmap.BioMegaSpruceTaiga:      false,
-	mcmap.BioMegaSpruceTaigaHills: false,
-	mcmap.BioExtremeHillsPlusM:    false,
-	mcmap.BioSavannaM:             false,
-	mcmap.BioSavannaPlateauM:      false,
-	mcmap.BioMesaBryce:            false,
-	mcmap.BioMesaPlateauFM:        false,
-	mcmap.BioMesaPlateauM:         false,
-	mcmap.BioUncalculated:         false,
+// snowLines maps a biome to the lowest y coordinate that can have snow naturally.
+// TODO: Get the actual values that Minecraft uses (could not find them).
+var snowLines = map[mcmap.Biome]int{
+	mcmap.BioOcean:                mcmap.ChunkSizeY,
+	mcmap.BioPlains:               mcmap.ChunkSizeY,
+	mcmap.BioDesert:               mcmap.ChunkSizeY,
+	mcmap.BioExtremeHills:         95,
+	mcmap.BioForest:               mcmap.ChunkSizeY,
+	mcmap.BioTaiga:                mcmap.ChunkSizeY,
+	mcmap.BioSwampland:            mcmap.ChunkSizeY,
+	mcmap.BioRiver:                mcmap.ChunkSizeY,
+	mcmap.BioHell:                 mcmap.ChunkSizeY,
+	mcmap.BioSky:                  mcmap.ChunkSizeY,
+	mcmap.BioFrozenOcean:          0,
+	mcmap.BioFrozenRiver:          0,
+	mcmap.BioIcePlains:            0,
+	mcmap.BioIceMountains:         0,
+	mcmap.BioMushroomIsland:       mcmap.ChunkSizeY,
+	mcmap.BioMushroomIslandShore:  mcmap.ChunkSizeY,
+	mcmap.BioBeach:                mcmap.ChunkSizeY,
+	mcmap.BioDesertHills:          mcmap.ChunkSizeY,
+	mcmap.BioForestHills:          mcmap.ChunkSizeY,
+	mcmap.BioTaigaHills:           0,
+	mcmap.BioExtremeHillsEdge:     95,
+	mcmap.BioJungle:               mcmap.ChunkSizeY,
+	mcmap.BioJungleHills:          mcmap.ChunkSizeY,
+	mcmap.BioJungleEdge:           mcmap.ChunkSizeY,
+	mcmap.BioDeepOcean:            mcmap.ChunkSizeY,
+	mcmap.BioStoneBeach:           mcmap.ChunkSizeY,
+	mcmap.BioColdBeach:            0,
+	mcmap.BioBirchForest:          mcmap.ChunkSizeY,
+	mcmap.BioBirchForestHills:     mcmap.ChunkSizeY,
+	mcmap.BioRoofedForest:         mcmap.ChunkSizeY,
+	mcmap.BioColdTaiga:            0,
+	mcmap.BioColdTaigaHills:       0,
+	mcmap.BioMegaTaiga:            mcmap.ChunkSizeY,
+	mcmap.BioMegaTaigaHills:       mcmap.ChunkSizeY,
+	mcmap.BioExtremeHillsPlus:     95,
+	mcmap.BioSavanna:              mcmap.ChunkSizeY,
+	mcmap.BioSavannaPlateau:       mcmap.ChunkSizeY,
+	mcmap.BioMesa:                 mcmap.ChunkSizeY,
+	mcmap.BioMesaPlateauF:         mcmap.ChunkSizeY,
+	mcmap.BioMesaPlateau:          mcmap.ChunkSizeY,
+	mcmap.BioSunflowerPlains:      mcmap.ChunkSizeY,
+	mcmap.BioDesertM:              mcmap.ChunkSizeY,
+	mcmap.BioExtremeHillsM:        95,
+	mcmap.BioFlowerForest:         mcmap.ChunkSizeY,
+	mcmap.BioTaigaM:               mcmap.ChunkSizeY,
+	mcmap.BioSwamplandM:           mcmap.ChunkSizeY,
+	mcmap.BioIcePlainsSpikes:      0,
+	mcmap.BioIceMountainsSpikes:   0,
+	mcmap.BioJungleM:              mcmap.ChunkSizeY,
+	mcmap.BioJungleEdgeM:          mcmap.ChunkSizeY,
+	mcmap.BioBirchForestM:         mcmap.ChunkSizeY,
+	mcmap.BioBirchForestHillsM:    mcmap.ChunkSizeY,
+	mcmap.BioRoofedForestM:        mcmap.ChunkSizeY,
+	mcmap.BioColdTaigaM:           0,
+	mcmap.BioMegaSpruceTaiga:      mcmap.ChunkSizeY,
+	mcmap.BioMegaSpruceTaigaHills: mcmap.ChunkSizeY,
+	mcmap.BioExtremeHillsPlusM:    95,
+	mcmap.BioSavannaM:             mcmap.ChunkSizeY,
+	mcmap.BioSavannaPlateauM:      mcmap.ChunkSizeY,
+	mcmap.BioMesaBryce:            mcmap.ChunkSizeY,
+	mcmap.BioMesaPlateauFM:        mcmap.ChunkSizeY,
+	mcmap.BioMesaPlateauM:         mcmap.ChunkSizeY,
+	mcmap.BioUncalculated:         mcmap.ChunkSizeY,
 }
diff --git a/region_wrapper.go b/region_wrapper.go
index 2f8abe4..bf23913 100644
--- a/region_wrapper.go
+++ b/region_wrapper.go
@@ -242,9 +242,18 @@ func (rw *RegionWrapper) GetBiomeAt(x, z int) (mcmap.Biome, bool) {
 	return chunk.Biome(bx, bz), true
 }
 
-func fixFreeze(bx, bz int, chunk *mcmap.Chunk) (newcol *gdk.Color) {
-	for y := mcmap.ChunkSizeY - 1; y >= 0; y-- {
-		if blk := chunk.Block(bx, y, bz); blk.ID != mcmap.BlkAir {
+func fixWeather(bio mcmap.Biome, bx, bz int, chunk *mcmap.Chunk) (newcol *gdk.Color) {
+	snowLine := snowLines[bio]
+
+	for y := mcmap.ChunkSizeY; y >= 0; y-- {
+		blk := chunk.Block(bx, y, bz)
+
+		if blk.ID == mcmap.BlkAir {
+			continue
+		}
+
+		if y >= snowLine {
+			// Freeze water and cover blocks with snow
 			if (blk.ID == mcmap.BlkStationaryWater) || (blk.ID == mcmap.BlkWater) {
 				blk.ID = mcmap.BlkIce
 				newcol = blockColors[mcmap.BlkIce]
@@ -256,17 +265,8 @@ func fixFreeze(bx, bz int, chunk *mcmap.Chunk) (newcol *gdk.Color) {
 					newcol = blockColors[mcmap.BlkSnow]
 				}
 			}
-
-			break
-		}
-	}
-
-	return
-}
-
-func fixMelt(bx, bz int, chunk *mcmap.Chunk) (newcol *gdk.Color) {
-	for y := mcmap.ChunkSizeY - 1; y >= 0; y-- {
-		if blk := chunk.Block(bx, y, bz); blk.ID != mcmap.BlkAir {
+		} else {
+			// Melt ice and remove snow cover
 			if blk.ID == mcmap.BlkIce {
 				blk.ID = mcmap.BlkStationaryWater
 				blk.Data = 0x0
@@ -280,9 +280,9 @@ func fixMelt(bx, bz int, chunk *mcmap.Chunk) (newcol *gdk.Color) {
 					}
 				}
 			}
-
-			break
 		}
+
+		break
 	}
 
 	return
@@ -306,11 +306,7 @@ func (rw *RegionWrapper) SetBiomeAt(x, z int, bio mcmap.Biome) {
 
 	var newcol *gdk.Color
 	if rw.fixSnowIce {
-		if coldBiome[bio] {
-			newcol = fixFreeze(bx, bz, chunk)
-		} else {
-			newcol = fixMelt(bx, bz, chunk)
-		}
+		newcol = fixWeather(bio, bx, bz, chunk)
 	}
 
 	chunk.MarkModified()