roodletoof
96 lines
1.8 KiB
Go
96 lines
1.8 KiB
Go
package main
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import (
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"errors"
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color_lib "image/color"
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"github.com/hajimehoshi/ebiten/v2"
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"github.com/hajimehoshi/ebiten/v2/vector"
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)
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type Vec2 struct {
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x, y float32
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}
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func cursorPosition() Vec2 {
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x, y := ebiten.CursorPosition()
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return Vec2{
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x: float32(x),
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y: float32(y),
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}
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}
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type stroke struct {
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points []Vec2
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width float32
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color color_lib.Color
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}
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func (s *stroke) appendIfMoved(point Vec2) {
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if len(s.points) != 0 {
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lastPoint := s.points[len(s.points)-1]
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if lastPoint.x == point.x && lastPoint.y == point.y {
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return
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}
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}
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s.points = append(s.points, point)
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}
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func (s *stroke) drawLast(screen *ebiten.Image) error {
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if s.color == nil {
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return errors.New("stroke has nil color")
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}
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if len(s.points) == 0 {
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return nil
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}
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from := s.points[len(s.points)-1]
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vector.DrawFilledCircle(screen, from.x, from.y, s.width/2, s.color, true)
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if len(s.points) == 1 {
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return nil
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}
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to := s.points[len(s.points)-2]
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vector.StrokeLine(
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screen,
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from.x,
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from.y,
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to.x,
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to.y,
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s.width,
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s.color,
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true,
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)
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vector.DrawFilledCircle(screen, to.x, to.y, s.width/2, s.color, true)
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return nil
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}
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func (s *stroke) draw(screen *ebiten.Image) error {
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if s.color == nil {
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return errors.New("stroke has nil color")
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}
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from := s.points[0]
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vector.DrawFilledCircle(screen, from.x, from.y, s.width/2, s.color, true)
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for _, to := range s.points[1:] {
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vector.StrokeLine(
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screen,
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from.x,
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from.y,
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to.x,
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to.y,
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s.width,
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s.color,
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true,
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)
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vector.DrawFilledCircle(screen, to.x, to.y, s.width/2, s.color, true)
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from = to
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}
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return nil
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}
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