102 lines
2.2 KiB
Go
102 lines
2.2 KiB
Go
package simulation
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import (
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"fmt"
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"strings"
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"time"
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"github.com/charmbracelet/harmonica"
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)
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type System struct {
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Frame Frame
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Particles []*Particle
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}
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type Particle struct {
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Char string
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TailChar string
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Physics *harmonica.Projectile
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Hidden bool
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Shooting bool
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ExplosionCall func(x, y float64, width, height int) []*Particle
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}
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type Frame struct {
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Width int
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Height int
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}
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func FPS(n int) float64 {
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return (time.Second / time.Duration(n)).Seconds()
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}
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func RemoveParticleFromArray(s []*Particle, i int) []*Particle {
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s[i] = nil
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s[i] = s[len(s)-1]
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return s[:len(s)-1]
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}
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func (s *System) Update() {
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for i := len(s.Particles) - 1; i >= 0; i-- {
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p := s.Particles[i]
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pos := p.Physics.Position()
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// if the shooting particle is slow enough then hide it and call the explosion function
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if !p.Hidden && p.Shooting && p.Physics.Velocity().Y > -3 {
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p.Hidden = true
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if p.ExplosionCall != nil {
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s.Particles = append(s.Particles, p.ExplosionCall(pos.X, pos.Y, s.Frame.Width, s.Frame.Height)...)
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}
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}
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// remove particles that are hidden or out of the side/bottom of the frame
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if p.Hidden || pos.X > float64(s.Frame.Width) || pos.X < 0 || pos.Y > float64(s.Frame.Height) {
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s.Particles = RemoveParticleFromArray(s.Particles, i)
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} else {
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s.Particles[i].Physics.Update()
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}
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}
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}
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func (s *System) Visible(p *Particle) bool {
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pos := p.Physics.Position()
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x := int(pos.X)
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y := int(pos.Y)
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return !p.Hidden && y >= 0 && y < s.Frame.Height-1 && x >= 0 && x < s.Frame.Width-1
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}
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func (s *System) Render() string {
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var out strings.Builder
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plane := make([][]string, s.Frame.Height)
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for i := range plane {
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plane[i] = make([]string, s.Frame.Width)
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}
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for _, p := range s.Particles {
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if s.Visible(p) {
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pos := p.Physics.Position()
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plane[int(pos.Y)][int(pos.X)] = p.Char
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if p.Shooting {
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l := -int(p.Physics.Velocity().Y)
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for i := 1; i < l; i++ {
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y := int(pos.Y) + i
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if y > 0 && y < s.Frame.Height-1 {
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plane[y][int(pos.X)] = p.TailChar
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}
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}
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}
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}
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}
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for i := range plane {
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for _, col := range plane[i] {
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if col == "" {
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fmt.Fprint(&out, " ")
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} else {
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fmt.Fprint(&out, col)
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}
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}
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fmt.Fprint(&out, "\n")
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}
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return out.String()
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}
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