mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-13 22:47:26 +01:00
99 lines
2.6 KiB
Go
99 lines
2.6 KiB
Go
// Copyright 2015 Hajime Hoshi
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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 shape
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import (
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"github.com/hajimehoshi/ebiten"
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"image/color"
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"math"
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)
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func DrawEllipse(s *ebiten.Image, x, y, width, height int, clr color.Color) error {
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return s.DrawLines(&ellipsesLines{&rect{x, y, width, height, clr}, 0, 2 * math.Pi})
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}
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func DrawEllipses(s *ebiten.Image, rects ebiten.Rects) error {
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return s.DrawLines(&ellipsesLines{rects, 0, 2 * math.Pi})
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}
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func DrawArc(s *ebiten.Image, x, y, width, height int, angle0, angle1 float64, clr color.Color) error {
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return s.DrawLines(&ellipsesLines{&rect{x, y, width, height, clr}, angle0, angle1})
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}
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type ellipsesLines struct {
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ebiten.Rects
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angle0, angle1 float64
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}
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func (e *ellipsesLines) lineNum() int {
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return 64
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}
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func (e *ellipsesLines) Len() int {
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return e.Rects.Len() * e.lineNum()
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}
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func round(x float64) int {
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return int(x + 0.5)
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}
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func (e *ellipsesLines) Points(i int) (x0, y0, x1, y1 int) {
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n := e.lineNum()
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x, y, w, h := e.Rects.Rect(i / n)
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part := float64(i % n)
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theta0 := 2 * math.Pi * part / float64(n)
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theta1 := 2 * math.Pi * (part + 1) / float64(n)
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if theta0 < e.angle0 || e.angle1 < theta1 {
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return 0, 0, 0, 0
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}
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theta0 = math.Max(theta0, e.angle0)
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theta1 = math.Min(theta1, e.angle1)
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theta0 = math.Mod(theta0, 2*math.Pi)
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theta1 = math.Mod(theta1, 2*math.Pi)
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fy0, fx0 := math.Sincos(theta0)
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fy1, fx1 := math.Sincos(theta1)
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hw, hh := (float64(w)-1)/2, (float64(h)-1)/2
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fx0 = fx0*hw + hw + float64(x)
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fx1 = fx1*hw + hw + float64(x)
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fy0 = fy0*hh + hh + float64(y)
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fy1 = fy1*hh + hh + float64(y)
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// TODO: The last fy1 may differ from first fy0 with very slightly difference,
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// which makes the lack of 1 pixel.
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return round(fx0), round(fy0), round(fx1), round(fy1)
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}
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func (e *ellipsesLines) Color(i int) color.Color {
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return e.Rects.Color(i / e.lineNum())
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}
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// TODO: This is same as ebiten.rect.
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type rect struct {
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x, y int
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width, height int
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color color.Color
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}
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func (r *rect) Len() int {
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return 1
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}
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func (r *rect) Rect(i int) (x, y, width, height int) {
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return r.x, r.y, r.width, r.height
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}
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func (r *rect) Color(i int) color.Color {
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return r.color
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}
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