69 lines
1.1 KiB
V
69 lines
1.1 KiB
V
module main
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import gg
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import gx
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const rate = f32(1) / 60 * 10
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struct App {
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mut:
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gg &gg.Context
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anim &Anim
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}
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struct Anim {
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mut:
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time f32
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reverse bool
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}
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fn (mut anim Anim) advance() {
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if anim.reverse {
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anim.time -= 1 * rate
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} else {
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anim.time += 1 * rate
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}
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// Use some arbitrary value that fits 60 fps
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if anim.time > 80 * rate || anim.time < -80 * rate {
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anim.reverse = !anim.reverse
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}
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}
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fn main() {
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mut app := &App{
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gg: 0
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anim: &Anim{}
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}
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app.gg = gg.new_context(
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bg_color: gx.rgb(174, 198, 255)
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width: 600
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height: 400
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window_title: 'Animated cubic Bézier curve'
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frame_fn: frame
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user_data: app
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)
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app.gg.run()
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}
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fn frame(mut app App) {
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time := app.anim.time
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p1_x := f32(200.0)
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p1_y := f32(200.0) + (10 * time)
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p2_x := f32(400.0)
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p2_y := f32(200.0) + (10 * time)
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ctrl_p1_x := f32(200.0) + (40 * time)
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ctrl_p1_y := f32(100.0)
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ctrl_p2_x := f32(400.0) + (-40 * time)
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ctrl_p2_y := f32(100.0)
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points := [p1_x, p1_y, ctrl_p1_x, ctrl_p1_y, ctrl_p2_x, ctrl_p2_y, p2_x, p2_y]
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app.gg.begin()
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app.gg.draw_cubic_bezier(points, gx.blue)
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app.gg.end()
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app.anim.advance()
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}
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