From 0e4e17ced7f2be3f9295458fdbd1b5e4762c935a Mon Sep 17 00:00:00 2001
From: Edgaru089 <sjs333@outlook.com>
Date: Wed, 2 Feb 2022 01:52:02 +0800
Subject: [PATCH] world: fix worldgen

---
 internal/util/unsafe.go             | 42 +++++++++++++++++++++++++++++
 internal/world/render.go            |  5 ++--
 internal/world/worldgen/worldgen.go | 12 ++++-----
 3 files changed, 51 insertions(+), 8 deletions(-)
 create mode 100644 internal/util/unsafe.go

diff --git a/internal/util/unsafe.go b/internal/util/unsafe.go
new file mode 100644
index 0000000..c2dd105
--- /dev/null
+++ b/internal/util/unsafe.go
@@ -0,0 +1,42 @@
+package util
+
+import (
+	"fmt"
+	"reflect"
+	"unsafe"
+)
+
+// Ptr returns the pointer to these things:
+//   - First element of a slice or array, nil if it has zero length;
+//   - The pointer itself if the parameter is a pointer, pointing to an scalar value.
+// It panics otherwise.
+func Ptr(d interface{}) (addr unsafe.Pointer) {
+	if d == nil {
+		return unsafe.Pointer(nil)
+	}
+
+	v := reflect.ValueOf(d)
+	switch v.Type().Kind() {
+	case reflect.Ptr:
+		e := v.Elem()
+		switch e.Kind() {
+		case
+			reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+			reflect.Float32, reflect.Float64:
+			addr = unsafe.Pointer(e.UnsafeAddr())
+		default:
+			panic(fmt.Errorf("unsupported pointer to type %s; must be a slice or pointer to a singular scalar value or the first element of an array or slice", e.Kind()))
+		}
+
+	case reflect.Slice, reflect.Array:
+		if v.Len() != 0 {
+			addr = unsafe.Pointer(v.Index(0).UnsafeAddr())
+		}
+	case reflect.Uintptr:
+		addr = unsafe.Pointer(d.(uintptr))
+	default:
+		panic(fmt.Errorf("unsupported type %s; must be a slice or pointer to a singular scalar value or the first element of an array or slice", v.Type()))
+	}
+	return
+}
diff --git a/internal/world/render.go b/internal/world/render.go
index ca68a51..1eabb66 100644
--- a/internal/world/render.go
+++ b/internal/world/render.go
@@ -7,6 +7,7 @@ import (
 
 	"edgaru089.ml/go/gl01/internal/asset"
 	"edgaru089.ml/go/gl01/internal/io"
+	"edgaru089.ml/go/gl01/internal/util"
 	"edgaru089.ml/go/gl01/internal/util/itype"
 	"github.com/go-gl/gl/all-core/gl"
 )
@@ -91,9 +92,9 @@ func (c *Chunk) updateRender() {
 	select {
 	case vert := <-c.vertUpdate:
 		gl.BindBuffer(gl.ARRAY_BUFFER, c.vbo)
-		gl.BufferData(gl.ARRAY_BUFFER, int(unsafe.Sizeof(Vertex{}))*len(vert[0]), gl.Ptr(vert[0]), gl.DYNAMIC_DRAW)
+		gl.BufferData(gl.ARRAY_BUFFER, int(unsafe.Sizeof(Vertex{}))*len(vert[0]), util.Ptr(vert[0]), gl.DYNAMIC_DRAW)
 		gl.BindBuffer(gl.ARRAY_BUFFER, c.water.vbo)
-		gl.BufferData(gl.ARRAY_BUFFER, int(unsafe.Sizeof(Vertex{}))*len(vert[1]), gl.Ptr(vert[1]), gl.DYNAMIC_DRAW)
+		gl.BufferData(gl.ARRAY_BUFFER, int(unsafe.Sizeof(Vertex{}))*len(vert[1]), util.Ptr(vert[1]), gl.DYNAMIC_DRAW)
 		c.vbolen = len(vert[0])
 		c.water.vbolen = len(vert[1])
 	default: // do nothing
diff --git a/internal/world/worldgen/worldgen.go b/internal/world/worldgen/worldgen.go
index 8699d81..48863b5 100644
--- a/internal/world/worldgen/worldgen.go
+++ b/internal/world/worldgen/worldgen.go
@@ -13,11 +13,11 @@ const (
 	Beta  = 2 // harmonic scaling/spacing
 	N     = 3 // iterations
 
-	AltitudeDensity = 10 // Density of the noise in altitude
+	AltitudeDensity = 20 // Density of the noise in altitude
 
 	Sealevel = 63 // Space with Y=63 and lower should be the sea
-	Highest  = 84 // Highest part of the terrain
-	Lowest   = 60 // Lowest part of the terrain
+	Highest  = 74 // Highest part of the terrain
+	Lowest   = 54 // Lowest part of the terrain
 )
 
 var perlins map[int64]*perlin.Perlin
@@ -50,10 +50,10 @@ func Chunk(chunk *packworld.Chunk, world *packworld.World, seed int64) {
 	for x := 0; x < packworld.ChunkSizeX; x++ {
 		for z := 0; z < packworld.ChunkSizeZ; z++ {
 
-			height := Lowest + int(float64(Highest-Lowest)*p.Noise2D(
+			height := Lowest + int(float64(Highest-Lowest)*(p.Noise2D(
 				float64(offX+x)/AltitudeDensity,
-				float64(offZ+z)/AltitudeDensity))
-			//log.Printf("height = %d (noise=%.5f)", height, p.Noise2D(float64(offX+x), float64(offZ+z)))
+				float64(offZ+z)/AltitudeDensity)/2+0.5))
+			//log.Printf("height = %d (noise=%.5f)", height, p.Noise2D(float64(offX+x)/AltitudeDensity, float64(offZ+z)/AltitudeDensity)/2+0.5)
 
 			// water
 			for y := Sealevel; y > height; y-- {