delaunay mapgen 1st version

2019-11-13 23:03:16 +03:00
parent 939be2f0f1 999f48afe9
commit 04da543c30
22 changed files with 633 additions and 31 deletions
--- a/util/bresenham/bresenham.go
+++ b/util/bresenham/bresenham.go
@ -0,0 +1,183 @@
+package bresenham
+
+import (
+	"lab.zaar.be/thefish/alchemyst-go/engine/types"
+)
+
+// dx > dy; x1 < x2; y1 < y2
+func BresenhamDxXRYD(canvas types.Putable, From, To types.Coords, symFunc func() interface{}) {
+	dx, dy := To.X - From.X, 2*(To.Y - From.Y)
+	e, slope := dx, 2*dx
+	for ; dx != 0; dx-- {
+		canvas.Put(From.X, From.Y, symFunc())
+		From.X++
+		e -= dy
+		if e < 0 {
+			From.Y++
+			e += slope
+		}
+	}
+}
+
+// dy > dx; x1 < x2; y1 < y2
+func BresenhamDyXRYD(canvas types.Putable, From, To types.Coords, symFunc func() interface{}) {
+	dx, dy := 2*(To.X - From.X), To.Y - From.Y
+	e, slope := dy, 2*dy
+	for ; dy != 0; dy-- {
+		canvas.Put(From.X, From.Y, symFunc())
+		From.Y++
+		e -= dx
+		if e < 0 {
+			From.X++
+			e += slope
+		}
+	}
+}
+
+// dx > dy; x1 < x2; y1 > y2
+func BresenhamDxXRYU(canvas types.Putable, From, To types.Coords, symFunc func() interface{}) {
+	dx, dy := To.X - From.X, 2*(From.Y-To.Y)
+	e, slope := dx, 2*dx
+	for ; dx != 0; dx-- {
+		canvas.Put(From.X, From.Y, symFunc())
+		From.X++
+		e -= dy
+		if e < 0 {
+			From.Y--
+			e += slope
+		}
+	}
+}
+
+func BresenhamDyXRYU(canvas types.Putable, From, To types.Coords, symFunc func() interface{}) {
+	dx, dy := 2*(To.X - From.X), From.Y-To.Y
+	e, slope := dy, 2*dy
+	for ; dy != 0; dy-- {
+		canvas.Put(From.X, From.Y, symFunc())
+		From.Y--
+		e -= dx
+		if e < 0 {
+			From.X++
+			e += slope
+		}
+	}
+}
+
+// Generalized with integer
+func Bresenham(canvas types.Putable, From, To types.Coords, symFunc func() interface{}) {
+	var dx, dy, e, slope int
+
+	// Because drawing p1 -> p2 is equivalent to draw p2 -> p1,
+	// I sort points in x-axis order to handle only half of possible cases.
+	if From.X > To.X {
+		From.X, From.Y, To.X, To.Y = To.X, To.Y, From.X, From.Y
+	}
+
+	dx, dy = To.X - From.X, To.Y - From.Y
+	// Because point is x-axis ordered, dx cannot be negative
+	if dy < 0 {
+		dy = -dy
+	}
+
+	switch {
+
+	// Is line a point ?
+	case From.X ==To.X && From.Y ==To.Y:
+		canvas.Put(From.X, From.Y, symFunc())
+
+		// Is line an horizontal ?
+	case From.Y ==To.Y:
+		for ; dx != 0; dx-- {
+			canvas.Put(From.X, From.Y, symFunc())
+			From.X++
+		}
+		canvas.Put(From.X, From.Y, symFunc())
+
+		// Is line a vertical ?
+	case From.X ==To.X:
+		if From.Y > To.Y {
+			From.Y, To.Y = To.Y, From.Y
+		}
+		for ; dy != 0; dy-- {
+			canvas.Put(From.X, From.Y, symFunc())
+			From.Y++
+		}
+		canvas.Put(From.X, From.Y, symFunc())
+
+		// Is line a diagonal ?
+	case dx == dy:
+		if From.Y < To.Y {
+			for ; dx != 0; dx-- {
+				canvas.Put(From.X, From.Y, symFunc())
+				From.X++
+				From.Y++
+			}
+		} else {
+			for ; dx != 0; dx-- {
+				canvas.Put(From.X, From.Y, symFunc())
+				From.X++
+				From.Y--
+			}
+		}
+		canvas.Put(From.X, From.Y, symFunc())
+
+		// wider than high ?
+	case dx > dy:
+		if From.Y < To.Y {
+			// BresenhamDxXRYD(img, x1, y1, x2, y2, col)
+			dy, e, slope = 2*dy, dx, 2*dx
+			for ; dx != 0; dx-- {
+				canvas.Put(From.X, From.Y, symFunc())
+				From.X++
+				e -= dy
+				if e < 0 {
+					From.Y++
+					e += slope
+				}
+			}
+		} else {
+			// BresenhamDxXRYU(img, x1, y1, x2, y2, col)
+			dy, e, slope = 2*dy, dx, 2*dx
+			for ; dx != 0; dx-- {
+				canvas.Put(From.X, From.Y, symFunc())
+				From.X++
+				e -= dy
+				if e < 0 {
+					From.Y--
+					e += slope
+				}
+			}
+		}
+		canvas.Put(To.X, To.Y, symFunc())
+
+		// higher than wide.
+	default:
+		if From.Y < To.Y {
+			// BresenhamDyXRYD(img, x1, y1, x2, y2, col)
+			dx, e, slope = 2*dx, dy, 2*dy
+			for ; dy != 0; dy-- {
+				canvas.Put(From.X, From.Y, symFunc())
+				From.Y++
+				e -= dx
+				if e < 0 {
+					From.X++
+					e += slope
+				}
+			}
+		} else {
+			// BresenhamDyXRYU(img, x1, y1, x2, y2, col)
+			dx, e, slope = 2*dx, dy, 2*dy
+			for ; dy != 0; dy-- {
+				canvas.Put(From.X, From.Y, symFunc())
+				From.Y--
+				e -= dx
+				if e < 0 {
+					From.X++
+					e += slope
+				}
+			}
+		}
+		canvas.Put(To.X, To.Y, symFunc())
+		//img.Set(x2, y2, col)
+	}
+}