139 lines
2.8 KiB
Go
139 lines
2.8 KiB
Go
package main
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import (
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"math"
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"math/rand"
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"github.com/gen2brain/raylib-go/raylib"
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"github.com/vova616/chipmunk"
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"github.com/vova616/chipmunk/vect"
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)
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const (
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ballRadius = 25
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ballMass = 1
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)
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// Game type
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type Game struct {
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Space *chipmunk.Space
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Balls []*chipmunk.Shape
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StaticLines []*chipmunk.Shape
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ticksToNextBall int
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}
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// NewGame - Start new game
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func NewGame() (g Game) {
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g.Init()
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return
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}
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// Init - Initialize game
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func (g *Game) Init() {
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g.createBodies()
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g.ticksToNextBall = 10
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}
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// Update - Update game
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func (g *Game) Update() {
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g.ticksToNextBall--
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if g.ticksToNextBall == 0 {
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g.ticksToNextBall = rand.Intn(100) + 1
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g.addBall()
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}
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// Physics steps calculations
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g.step(rl.GetFrameTime())
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}
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// Draw - Draw game
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func (g *Game) Draw() {
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for i := range g.StaticLines {
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x := g.StaticLines[i].GetAsSegment().A.X
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y := g.StaticLines[i].GetAsSegment().A.Y
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x2 := g.StaticLines[i].GetAsSegment().B.X
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y2 := g.StaticLines[i].GetAsSegment().B.Y
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rl.DrawLine(int32(x), int32(y), int32(x2), int32(y2), rl.DarkBlue)
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}
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for _, b := range g.Balls {
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pos := b.Body.Position()
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rl.DrawCircleLines(int32(pos.X), int32(pos.Y), float32(ballRadius), rl.DarkBlue)
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}
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}
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// createBodies sets up the chipmunk space and static bodies
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func (g *Game) createBodies() {
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g.Space = chipmunk.NewSpace()
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g.Space.Gravity = vect.Vect{0, 900}
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staticBody := chipmunk.NewBodyStatic()
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g.StaticLines = []*chipmunk.Shape{
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chipmunk.NewSegment(vect.Vect{250.0, 240.0}, vect.Vect{550.0, 280.0}, 0),
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chipmunk.NewSegment(vect.Vect{550.0, 280.0}, vect.Vect{550.0, 180.0}, 0),
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}
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for _, segment := range g.StaticLines {
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segment.SetElasticity(0.6)
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staticBody.AddShape(segment)
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}
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g.Space.AddBody(staticBody)
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}
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// addBall adds ball to chipmunk space and body
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func (g *Game) addBall() {
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x := rand.Intn(600-200) + 200
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ball := chipmunk.NewCircle(vect.Vector_Zero, float32(ballRadius))
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ball.SetElasticity(0.95)
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body := chipmunk.NewBody(vect.Float(ballMass), ball.Moment(float32(ballMass)))
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body.SetPosition(vect.Vect{vect.Float(x), 0.0})
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body.SetAngle(vect.Float(rand.Float32() * 2 * math.Pi))
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body.AddShape(ball)
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g.Space.AddBody(body)
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g.Balls = append(g.Balls, ball)
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}
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// step advances the physics engine and cleans up any balls that are off-screen
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func (g *Game) step(dt float32) {
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g.Space.Step(vect.Float(dt))
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for i := 0; i < len(g.Balls); i++ {
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p := g.Balls[i].Body.Position()
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if p.Y < -100 {
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g.Space.RemoveBody(g.Balls[i].Body)
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g.Balls[i] = nil
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g.Balls = append(g.Balls[:i], g.Balls[i+1:]...)
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i-- // consider same index again
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}
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}
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}
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func main() {
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rl.InitWindow(800, 450, "raylib [physics] example - chipmunk")
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rl.SetTargetFPS(60)
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game := NewGame()
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for !rl.WindowShouldClose() {
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rl.BeginDrawing()
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rl.ClearBackground(rl.RayWhite)
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game.Update()
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game.Draw()
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rl.EndDrawing()
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}
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rl.CloseWindow()
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}
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