refactor: bitmap package

pkg/bitmap/bitmap.go

@@ -0,0 +1,121 @@
+package bitmap
+
+import (
+	"fmt"
+	"math"
+)
+
+const intSize = 32
+
+type bitmap struct {
+	width     uint32
+	height    uint32
+	bitVector []uint32
+}
+
+func NewBitmap(width uint32, height uint32) bitmap {
+	return bitmap{width: width, height: height, bitVector: make([]uint32, int(math.Ceil(float64(width*height)/intSize)))}
+}
+
+func (p bitmap) Set(x, y int) {
+	boundX := (p.width + uint32(x)) % p.width
+	boundY := (p.height + uint32(y)) % p.height
+	p.set(boundX + boundY*p.width)
+}
+
+func (p bitmap) set(number uint32) {
+	p.bitVector[number/intSize] |= (0b1 << (number % intSize))
+}
+
+func (p bitmap) IsSet(x, y int) bool {
+	return p.isSet(uint32(x) + uint32(y)*p.width)
+}
+
+func (p bitmap) isSet(number uint32) bool {
+	return p.bitVector[number/intSize]&(0b1<<(number%intSize)) > 0
+}
+
+func (p bitmap) Circle(x, y int, r float64) {
+	plotX := 0
+	plotY := int(math.Ceil(r))
+	delta := 3 - 2*plotY
+	lastY := plotY
+	for plotX <= plotY {
+		p.octant(x, y, plotX, plotY)
+		if plotY < lastY {
+			for lineX := 0; lineX < plotX; lineX++ {
+				p.octant(x, y, lineX, plotY)
+			}
+			lastY = plotY
+		}
+		if delta < 0 {
+			delta += 4*plotX + 6
+		} else {
+			delta += 4*(plotX-plotY) + 10
+			plotY -= 1
+		}
+		plotX += 1
+	}
+	for fillX := 0; fillX < plotX; fillX++ {
+		for fillY := 0; fillY <= fillX; fillY++ {
+			p.octant(x, y, fillX, fillY)
+		}
+	}
+}
+
+func (p bitmap) CircleAdjacent(x, y int, r float64) {
+	plotX := 0
+	plotY := int(math.Ceil(r))
+	delta := 1 - 2*plotY
+	err := 0
+	for plotX <= plotY {
+		p.octant(x, y, plotX, plotY)
+		err = 2*(delta+plotY) - 1
+		if delta < 0 && err <= 0 {
+			plotX += 1
+			delta += 2*plotX + 1
+			continue
+		}
+		if delta > 0 && err > 0 {
+			plotY -= 1
+			delta -= 2*plotY + 1
+			continue
+		}
+		plotX += 1
+		plotY -= 1
+		delta += 2 * (plotX - plotY)
+	}
+}
+
+func (p bitmap) octant(x, y int, plotX, plotY int) {
+	p.Set(x+plotX, y+plotY)
+	p.Set(x+plotX, y-plotY)
+	p.Set(x-plotX, y+plotY)
+	p.Set(x-plotX, y-plotY)
+	p.Set(x+plotY, y+plotX)
+	p.Set(x+plotY, y-plotX)
+	p.Set(x-plotY, y+plotX)
+	p.Set(x-plotY, y-plotX)
+}
+
+func (p bitmap) Clear() {
+	for i := range p.bitVector {
+		p.bitVector[i] &= 0
+	}
+}
+
+func (p bitmap) String() string {
+	px := map[bool]string{true: "██", false: "░░"}
+	var result string
+	cnt := 0
+	for i := 0; i < len(p.bitVector); i++ {
+		for bit := 0; bit < intSize && cnt < int(p.width*p.height); bit++ {
+			result += fmt.Sprintf("%s", px[p.bitVector[i]&(0b1<<bit) > 0])
+			cnt++
+			if cnt%int(p.width) == 0 {
+				result += "\n"
+			}
+		}
+	}
+	return result
+}