Remove custom physics package in favour of harmonica

confetti/confetti.go

@@ -4,8 +4,8 @@ import (
 	"math/rand"
 	"time"
 
+	"github.com/charmbracelet/harmonica"
 	"github.com/maaslalani/confetty/array"
-	"github.com/maaslalani/confetty/physics"
 	"github.com/maaslalani/confetty/simulation"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -43,11 +43,11 @@ func Spawn(width, height int) []simulation.Particle {
 		y := float64(0)
 
 		p := simulation.Particle{
-			Physics: physics.New(
+			Physics: harmonica.NewProjectile(
-				physics.Point{X: x + (float64(width/4) * (rand.Float64() - 0.5)), Y: y},
+				harmonica.FPS(framesPerSecond),
-				physics.Vector{X: (rand.Float64() - 0.5) * 100, Y: rand.Float64() * 50},
+				harmonica.Point{X: x + (float64(width/4) * (rand.Float64() - 0.5)), Y: y, Z: 0},
-				physics.Vector(physics.Gravity),
+				harmonica.Vector{X: (rand.Float64() - 0.5) * 100, Y: rand.Float64() * 50, Z: 0},
-				framesPerSecond,
+				harmonica.Vector(harmonica.TerminalGravity),
 			),
 			Char: lipgloss.NewStyle().
 				Foreground(lipgloss.Color(array.Sample(colors))).

fireworks/fireworks.go

@@ -5,8 +5,8 @@ import (
 	"math/rand"
 	"time"
 
+	"github.com/charmbracelet/harmonica"
 	"github.com/maaslalani/confetty/array"
-	"github.com/maaslalani/confetty/physics"
 	"github.com/maaslalani/confetty/simulation"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -48,11 +48,11 @@ func Spawn(width, height int) []simulation.Particle {
 
 	for i := 0; i < numParticles; i++ {
 		p := simulation.Particle{
-			Physics: physics.New(
+			Physics: harmonica.NewProjectile(
-				physics.Point{X: x, Y: y},
+				harmonica.FPS(framesPerSecond),
-				physics.Vector{X: math.Cos(float64(i)) * v, Y: math.Sin(float64(i)) * v / 2},
+				harmonica.Point{X: x, Y: y},
-				physics.Vector(physics.Gravity),
+				harmonica.Vector{X: math.Cos(float64(i)) * v, Y: math.Sin(float64(i)) * v / 2},
-				framesPerSecond,
+				harmonica.Vector(harmonica.TerminalGravity),
 			),
 			Char: lipgloss.NewStyle().Foreground(color).Render(array.Sample(characters)),
 		}

go.mod

@@ -5,6 +5,7 @@ go 1.16
 require (
 	github.com/charmbracelet/bubbles v0.8.0
 	github.com/charmbracelet/bubbletea v0.14.1
+	github.com/charmbracelet/harmonica v0.1.1-0.20211007155451-1466d67a1d68 // indirect
 	github.com/charmbracelet/lipgloss v0.3.0
 	github.com/spf13/cobra v1.2.1
 	golang.org/x/term v0.0.0-20210422114643-f5beecf764ed

go.sum

@@ -52,6 +52,8 @@ github.com/charmbracelet/bubbles v0.8.0/go.mod h1:5WX1sSSjNCgCrzvRMN/z23HxvWaa+A
 github.com/charmbracelet/bubbletea v0.13.1/go.mod h1:tp9tr9Dadh0PLhgiwchE5zZJXm5543JYjHG9oY+5qSg=
 github.com/charmbracelet/bubbletea v0.14.1 h1:pD/bM5LBEH/nDo7nKcgNUgi4uRHQhpWTIHZbG5vuSlc=
 github.com/charmbracelet/bubbletea v0.14.1/go.mod h1:b5lOf5mLjMg1tRn1HVla54guZB+jvsyV0yYAQja95zE=
+github.com/charmbracelet/harmonica v0.1.1-0.20211007155451-1466d67a1d68 h1:Gsc/gIm3Fwp9P1hz0tY+7fJR7fASRsGacIErx5+B7uU=
+github.com/charmbracelet/harmonica v0.1.1-0.20211007155451-1466d67a1d68/go.mod h1:KSri/1RMQOZLbw7AHqgcBycp8pgJnQMYYT8QZRqZ1Ao=
 github.com/charmbracelet/lipgloss v0.1.2/go.mod h1:5D8zradw52m7QmxRF6QgwbwJi9je84g8MkWiGN07uKg=
 github.com/charmbracelet/lipgloss v0.3.0 h1:5MysOD6sHr4RP4jkZNWGVIul5GKoOsP12NgbgXPvAlA=
 github.com/charmbracelet/lipgloss v0.3.0/go.mod h1:VkhdBS2eNAmRkTwRKLJCFhCOVkjntMusBDxv7TXahuk=

physics/physics.go

@@ -1,101 +0,0 @@
-package physics
-
-import (
-	"math"
-)
-
-// Position is the location of an object on a 2-dimensional plane
-type Position Point
-
-// Velocity is the velocity vector of an object's motion
-type Velocity Vector
-
-// Acceleration is the acceleration vector of an object's motion
-type Acceleration Vector
-
-// Gravity is the acceleration of gravity
-// Downward (+) by g m/s²
-var Gravity = Acceleration{
-	X: 0,
-	Y: 9.81,
-}
-
-// Motion represents an objects motion
-// it keeps track of the position, velocity, and acceleration
-type Motion struct {
-	pos Position
-	vel Velocity
-	acc Acceleration
-}
-
-// Physics tracks the current motion and initial motion of an object along with
-// fps to account for the Update in frames rather than per second
-type Physics struct {
-	current Motion
-	initial Motion
-	fps     float64
-}
-
-// Vector represents a magnitude and a direction in the form of a Point
-// from the origin (0, 0)
-type Vector struct {
-	X float64
-	Y float64
-}
-
-// Point is a coordinate on a 2-dimensional plane
-type Point struct {
-	X float64
-	Y float64
-}
-
-// Distance calculates the euclidean distance between two points
-func (a Point) Distance(b Point) float64 {
-	return math.Sqrt(math.Pow(b.X-a.X, 2) + math.Pow(b.Y-a.Y, 2))
-}
-
-// New initialize a physics simulation with simple motion
-func New(pos Point, vel, acc Vector, fps float64) *Physics {
-	motion := Motion{
-		pos: Position(pos),
-		vel: Velocity(vel),
-		acc: Acceleration(acc),
-	}
-	return &Physics{
-		initial: motion,
-		current: motion,
-		fps:     fps,
-	}
-}
-
-// Reset resets the current motion back to the initial
-func (p *Physics) Reset() {
-	p.current = p.initial
-}
-
-// Update increases the position of the motion by the velocity
-// and increases the velocity by the acceleration
-func (p *Physics) Update() {
-	p.current.pos.X += p.current.vel.X / p.fps
-	p.current.pos.Y += p.current.vel.Y / p.fps
-
-	p.current.vel.X += p.current.acc.X / p.fps
-	p.current.vel.Y += p.current.acc.Y / p.fps
-}
-
-// Displacement calculates the displacement between the current position and
-// its initial position
-func (p Physics) Displacement() float64 {
-	return Point(p.initial.pos).Distance(Point(p.current.pos))
-}
-
-// PosX returns the integer value of the current x coordinate for motion
-// not to be confused with Posix :D
-func (p Physics) PosX() int {
-	return int(math.Round(p.current.pos.X))
-}
-
-// PosY returns the integer value of the current y coordinate for motion
-func (p Physics) PosY() int {
-	return int(math.Round(p.current.pos.Y))
-}

physics/physics_test.go

@@ -1,126 +0,0 @@
-package physics_test
-
-import (
-	"testing"
-	"time"
-
-	. "github.com/maaslalani/confetty/physics"
-)
-
-const fps = 60
-
-func simulate(p *Physics, d time.Duration) {
-	frames := int(d.Seconds() * fps)
-	for i := 0; i < frames; i++ {
-		p.Update()
-	}
-}
-
-func TestNew(t *testing.T) {
-	x := 8
-	y := 20
-
-	physics := New(Point{float64(x), float64(y)}, Vector{1, 1}, Vector(Gravity), 60)
-	if x != physics.PosX() {
-		t.Fatal("x coordinate unexpected")
-	}
-
-	if y != physics.PosY() {
-		t.Fatal("y coordinate unexpected")
-	}
-}
-
-func TestUpdate(t *testing.T) {
-	physics := New(Point{0, 0}, Vector{5, 5}, Vector(Gravity), float64(fps))
-
-	// coordinates is the location at which the object should be
-	// after i+1 seconds of simulation.
-	coordinates := []Point{
-		{5, 10},
-		{10, 29},
-		{15, 59},
-		{20, 98},
-		{25, 147},
-		{30, 206},
-		{35, 275},
-	}
-
-	for _, c := range coordinates {
-		simulate(physics, time.Second)
-
-		x := physics.PosX()
-		y := physics.PosY()
-
-		if x != int(c.X) {
-			t.Logf("Want: %d, Got: %d", x, int(c.X))
-			t.Fatal("x coordinate unexpected")
-		}
-		if y != int(c.Y) {
-			t.Logf("Want: %d, Got: %d", y, int(c.Y))
-			t.Fatal("y coordinate unexpected")
-		}
-	}
-}
-
-func TestDisplacement(t *testing.T) {
-	tt := []struct {
-		x   int
-		y   int
-		vel Vector
-		d   float64
-	}{
-		{x: 5, y: 5, vel: Vector{5, 10}, d: 11.180339887498933},
-		{x: 0, y: 0, vel: Vector{1, 1}, d: 1.414213562373097},
-	}
-
-	for _, tc := range tt {
-		physics := New(Point{float64(tc.x), float64(tc.y)}, tc.vel, Vector{}, float64(fps))
-
-		simulate(physics, time.Second)
-
-		if physics.Displacement() != tc.d {
-			t.Log(physics.Displacement())
-			t.Fatal("expected displacement to be 15")
-		}
-	}
-}
-
-func TestReset(t *testing.T) {
-	x := 5
-	y := 10
-	vel := Vector{20, 20}
-
-	physics := New(Point{float64(x), float64(y)}, vel, Vector(Gravity), float64(fps))
-
-	simulate(physics, time.Second)
-
-	// store the current position after 1 second of simulation we will simulate 1
-	// second again and ensure that the object reaches the same position, we
-	// don't care what the position is but if the object reaches the same
-	// position again then we ensure that the velocity and acceleration was reset
-	cx := physics.PosX()
-	cy := physics.PosY()
-
-	physics.Reset()
-
-	if physics.PosX() != x {
-		t.Fatal("expected x to be reset")
-	}
-
-	if physics.PosY() != y {
-		t.Fatal("expected y to be reset")
-	}
-
-	// here we are simply checking that the object reaches the same position
-	// after being reset in the same amount of time. This ensures velocity and
-	// acceleration were reset without checking them explicitly
-	simulate(physics, time.Second)
-
-	if physics.PosX() != cx {
-		t.Fatal("expected simulation to be repeatable")
-	}
-
-	if physics.PosY() != cy {
-		t.Fatal("expected simulation to be repeatable")
-	}
-}

simulation/simulation.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/maaslalani/confetty/physics"
+	"github.com/charmbracelet/harmonica"
 )
 
 type System struct {
@@ -14,7 +14,7 @@ type System struct {
 
 type Particle struct {
 	Char    string
-	Physics *physics.Physics
+	Physics *harmonica.Projectile
 	Hidden  bool
 }
 
@@ -39,8 +39,8 @@ func (s *System) Update() {
 }
 
 func (s *System) Visible(p Particle) bool {
-	y := p.Physics.PosY()
+	y := int(p.Physics.Position().Y)
-	x := p.Physics.PosX()
+	x := int(p.Physics.Position().X)
 	return y >= 0 && y < s.Frame.Height-1 && x >= 0 && x < s.Frame.Width-1
 }
 
@@ -52,7 +52,7 @@ func (s *System) Render() string {
 	}
 	for _, p := range s.Particles {
 		if s.Visible(p) {
-			plane[p.Physics.PosY()][p.Physics.PosX()] = p.Char
+			plane[int(p.Physics.Position().Y)][int(p.Physics.Position().X)] = p.Char
 		}
 	}
 	for i := range plane {