From 15dbe41db20d6d3daa7e44b7ac9ca73a8bd43106 Mon Sep 17 00:00:00 2001
From: Maas Lalani <maaslalani0@gmail.com>
Date: Fri, 6 Aug 2021 22:00:08 -0400
Subject: [PATCH] simple physics refactor

---
 README.md                |  3 +++
 pkg/confetty/confetty.go | 42 ++++++++++++------------------------
 pkg/physics/physics.go   | 46 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 28 deletions(-)
 create mode 100644 README.md
 create mode 100644 pkg/physics/physics.go

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..4bde715
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# ConfeTTY
+
+Terminal Confetti.
diff --git a/pkg/confetty/confetty.go b/pkg/confetty/confetty.go
index 748bc0b..c01306d 100644
--- a/pkg/confetty/confetty.go
+++ b/pkg/confetty/confetty.go
@@ -2,11 +2,12 @@ package confetty
 
 import (
 	"fmt"
-	"math"
 	"math/rand"
 	"strings"
 	"time"
 
+	"github.com/maaslalani/confetty/pkg/physics"
+
 	"github.com/charmbracelet/bubbles/viewport"
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
@@ -46,26 +47,9 @@ type model struct {
 }
 
 type Particle struct {
-	char  string
-	acc   Acceleration
-	vel   Velocity
-	pos   Position
-	color lipgloss.Color
-}
-
-type Position struct {
-	x float64
-	y float64
-}
-
-type Velocity struct {
-	x float64
-	y float64
-}
-
-type Acceleration struct {
-	x float64
-	y float64
+	char    string
+	physics *physics.Physics
+	color   lipgloss.Color
 }
 
 var characters = []string{"▄", "▀", "█"} // "▓", "▒", "░"}
@@ -84,9 +68,12 @@ func InitialModel() model {
 
 		p := &Particle{
 			char: lipgloss.NewStyle().Foreground(colors[rand.Intn(len(colors))]).Render(characters[rand.Intn(len(characters))]),
-			pos:  Position{x: x, y: y},
-			vel:  Velocity{x: (rand.Float64() - 0.5) * 100, y: (rand.Float64() - 0.5) * 100},
-			acc:  Acceleration{x: 0, y: 9.8},
+			physics: physics.New(
+				physics.Vector{X: x, Y: y},
+				physics.Vector{X: (rand.Float64() - 0.5) * 100, Y: (rand.Float64() - 0.5) * 100},
+				physics.Vector(physics.Gravity),
+				fps,
+			),
 		}
 		particles = append(particles, p)
 	}
@@ -104,8 +91,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		return m, tea.Quit
 	case frameMsg:
 		for _, p := range m.particles {
-			p.pos.y, p.vel.y = p.pos.y+p.vel.y/fps, p.vel.y+p.acc.y/fps
-			p.pos.x, p.vel.x = p.pos.x+p.vel.x/fps, p.vel.x+p.acc.x/fps
+			p.physics.Update()
 		}
 		return m, animate()
 	case tea.WindowSizeMsg:
@@ -127,8 +113,8 @@ func (m model) View() string {
 		grid[i] = make([]string, m.viewport.Width)
 	}
 	for _, p := range m.particles {
-		y := int(math.Round(p.pos.y))
-		x := int(math.Round(p.pos.x))
+		y := p.physics.PosY()
+		x := p.physics.PosX()
 		if y < 0 || x < 0 || x >= m.viewport.Width-1 || y >= m.viewport.Height-1 {
 			continue
 		}
diff --git a/pkg/physics/physics.go b/pkg/physics/physics.go
new file mode 100644
index 0000000..956b65a
--- /dev/null
+++ b/pkg/physics/physics.go
@@ -0,0 +1,46 @@
+package physics
+
+import "math"
+
+type Position Vector
+type Velocity Vector
+type Acceleration Vector
+
+var Gravity = Acceleration{
+	X: 0,
+	Y: 9.81,
+}
+
+type Physics struct {
+	pos Position
+	vel Velocity
+	acc Acceleration
+	fps float64
+}
+
+type Vector struct {
+	X float64
+	Y float64
+}
+
+func New(pos, vel, acc Vector, fps float64) *Physics {
+	return &Physics{
+		pos: Position(pos),
+		vel: Velocity(vel),
+		acc: Acceleration(acc),
+		fps: fps,
+	}
+}
+
+func (p *Physics) Update() {
+	p.pos.Y, p.vel.Y = p.pos.Y+p.vel.Y/p.fps, p.vel.Y+p.acc.Y/p.fps
+	p.pos.X, p.vel.X = p.pos.X+p.vel.X/p.fps, p.vel.X+p.acc.X/p.fps
+}
+
+func (p Physics) PosX() int {
+	return int(math.Round(p.pos.X))
+}
+
+func (p Physics) PosY() int {
+	return int(math.Round(p.pos.Y))
+}