mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-27 04:08:53 +01:00
57 lines
1.5 KiB
Go
57 lines
1.5 KiB
Go
// Copyright 2019 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package math
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import (
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"math"
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)
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type Point struct {
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X float32
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Y float32
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}
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type Vec2 struct {
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X float32
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Y float32
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}
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func (p Vec2) Cross(other Vec2) float32 {
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return p.X*other.Y - p.Y*other.X
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}
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type Segment struct {
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P0 Point
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P1 Point
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}
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func (s Segment) Translate(offset float32) Segment {
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a := math.Atan2(float64(s.P1.Y-s.P0.Y), float64(s.P1.X-s.P0.X))
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si, co := math.Sincos(a + math.Pi/2)
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dx, dy := float32(co)*offset, float32(si)*offset
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return Segment{
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P0: Point{s.P0.X + dx, s.P0.Y + dy},
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P1: Point{s.P1.X + dx, s.P1.Y + dy},
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}
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}
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func (s Segment) IntersectionAsLines(other Segment) Point {
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v1 := Vec2{other.P1.X - other.P0.X, other.P1.Y - other.P0.Y}
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d0 := v1.Cross(Vec2{s.P0.X - other.P0.X, s.P0.Y - other.P0.Y})
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d1 := -v1.Cross(Vec2{s.P1.X - other.P1.X, s.P1.Y - other.P1.Y})
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t := d0 / (d0 + d1)
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return Point{s.P0.X + (s.P1.X-s.P0.X)*t, s.P0.Y + (s.P1.Y-s.P0.Y)*t}
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}
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