Ilia Denisov
82 lines
1.5 KiB
Go
82 lines
1.5 KiB
Go
package util
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import "math"
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func ShortDistance(w, h uint32, x1, y1, x2, y2 float64) float64 {
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return math.Hypot(deltas(w, h, x1, y1, x2, y2))
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}
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func NextTravelCoord(w, h uint32, x1, y1, x2, y2, delta float64) (float64, float64, bool) {
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deltaX, deltaY := deltas(w, h, x1, y1, x2, y2)
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distance := math.Hypot(deltaX, deltaY)
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if distance <= delta {
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return x2, y2, true
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}
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// [ ] refactor - remove extra vars
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xa := 0.
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ya := 0.
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xb := deltaX
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yb := deltaY
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d := distance
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d2 := delta
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xc := xa - (d2*(xa-xb))/d
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yc := ya - (d2*(ya-yb))/d
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// ---
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var tx, ty float64
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if math.Abs(x2-x1) > float64(w/2) {
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// moving across X boundary
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if x2 < x1 {
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// moving across higher border
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tx = math.Mod(x1+xc, float64(w))
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} else {
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// moving across lower border
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tx = x1 - xc
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if tx < 0 {
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tx = float64(w) + tx
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}
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}
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} else {
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if x2 < x1 {
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tx = x1 - xc
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} else {
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tx = x1 + xc
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}
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}
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if math.Abs(y2-y1) > float64(h/2) {
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// moving across Y boundary
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if y2 < y1 {
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// moving across higher border
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ty = math.Mod(y1+yc, float64(h))
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} else {
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// moving across lower border
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ty = y1 - yc
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if ty < 0 {
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ty = float64(h) + ty
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}
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}
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} else {
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if y2 < y1 {
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ty = y1 - yc
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} else {
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ty = y1 + yc
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}
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}
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return tx, ty, false
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}
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func deltas(w, h uint32, x1, y1, x2, y2 float64) (float64, float64) {
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dx := math.Abs(x2 - x1)
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dy := math.Abs(y2 - y1)
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if dx > float64(w/2) {
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dx = float64(h) - dx
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}
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if dy > float64(h/2) {
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dy = float64(h) - dy
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}
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return dx, dy
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}
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