use jakecoffman port of chipmunk instead of vova616
This commit is contained in:
jake
parent
eec2b1e494
commit
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1 changed files with 130 additions and 106 deletions
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@ -1,139 +1,163 @@
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package main
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import (
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"fmt"
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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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"github.com/jakecoffman/cp"
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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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var grabbableMaskBit uint = 1 << 31
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var grabFilter = cp.ShapeFilter{
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cp.NO_GROUP, grabbableMaskBit, grabbableMaskBit,
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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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func randUnitCircle() cp.Vector {
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v := cp.Vector{X: rand.Float64()*2.0 - 1.0, Y: rand.Float64()*2.0 - 1.0}
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if v.LengthSq() < 1.0 {
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return v
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}
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return randUnitCircle()
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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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var simpleTerrainVerts = []cp.Vector{
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{350.00, 425.07}, {336.00, 436.55}, {272.00, 435.39}, {258.00, 427.63}, {225.28, 420.00}, {202.82, 396.00},
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{191.81, 388.00}, {189.00, 381.89}, {173.00, 380.39}, {162.59, 368.00}, {150.47, 319.00}, {128.00, 311.55},
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{119.14, 286.00}, {126.84, 263.00}, {120.56, 227.00}, {141.14, 178.00}, {137.52, 162.00}, {146.51, 142.00},
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{156.23, 136.00}, {158.00, 118.27}, {170.00, 100.77}, {208.43, 84.00}, {224.00, 69.65}, {249.30, 68.00},
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{257.00, 54.77}, {363.00, 45.94}, {374.15, 54.00}, {386.00, 69.60}, {413.00, 70.73}, {456.00, 84.89},
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{468.09, 99.00}, {467.09, 123.00}, {464.92, 135.00}, {469.00, 141.03}, {497.00, 148.67}, {513.85, 180.00},
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{509.56, 223.00}, {523.51, 247.00}, {523.00, 277.00}, {497.79, 311.00}, {478.67, 348.00}, {467.90, 360.00},
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{456.76, 382.00}, {432.95, 389.00}, {417.00, 411.32}, {373.00, 433.19}, {361.00, 430.02}, {350.00, 425.07},
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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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// creates a circle with random placement
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func addCircle(space *cp.Space, radius float64) {
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mass := radius * radius / 25.0
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body := space.AddBody(cp.NewBody(mass, cp.MomentForCircle(mass, 0, radius, cp.Vector{})))
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body.SetPosition(randUnitCircle().Mult(180))
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shape := space.AddShape(cp.NewCircle(body, radius, cp.Vector{}))
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shape.SetElasticity(0)
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shape.SetFriction(0.9)
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}
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// creates a simple terrain to contain bodies
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func simpleTerrain() *cp.Space {
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space := cp.NewSpace()
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space.Iterations = 10
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space.SetGravity(cp.Vector{0, -100})
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space.SetCollisionSlop(0.5)
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offset := cp.Vector{X: -320, Y: -240}
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for i := 0; i < len(simpleTerrainVerts)-1; i++ {
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a := simpleTerrainVerts[i]
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b := simpleTerrainVerts[i+1]
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space.AddShape(cp.NewSegment(space.StaticBody, a.Add(offset), b.Add(offset), 0))
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}
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// Physics steps calculations
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g.step(raylib.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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raylib.DrawLine(int32(x), int32(y), int32(x2), int32(y2), raylib.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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raylib.DrawCircleLines(int32(pos.X), int32(pos.Y), float32(ballRadius), raylib.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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return space
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}
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func main() {
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raylib.InitWindow(800, 450, "raylib [physics] example - chipmunk")
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const width, height = 800, 450
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const physicsTickrate = 1.0 / 60.0
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raylib.SetTargetFPS(60)
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raylib.SetConfigFlags(raylib.FlagVsyncHint)
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raylib.InitWindow(width, height, "raylib [physics] example - chipmunk")
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game := NewGame()
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offset := raylib.Vector2{X: width / 2, Y: height / 2}
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// since the example ported from elsewhere, flip the camera 180 and offset to center it
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camera := raylib.NewCamera2D(offset, raylib.Vector2{}, 180, 1)
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space := simpleTerrain()
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for i := 0; i < 1000; i++ {
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addCircle(space, 5)
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}
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mouseBody := cp.NewKinematicBody()
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var mouse cp.Vector
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var mouseJoint *cp.Constraint
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var accumulator, dt float32
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lastTime := raylib.GetTime()
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for !raylib.WindowShouldClose() {
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// calculate dt
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now := raylib.GetTime()
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dt = now - lastTime
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lastTime = now
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// update the mouse position
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mousePos := raylib.GetMousePosition()
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// alter the mouse coordinates based on the camera position, rotation
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mouse.X = float64(mousePos.X-camera.Offset.X) * -1
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mouse.Y = float64(mousePos.Y-camera.Offset.Y) * -1
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// smooth mouse movements to new position
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newPoint := mouseBody.Position().Lerp(mouse, 0.25)
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mouseBody.SetVelocityVector(newPoint.Sub(mouseBody.Position()).Mult(60.0))
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mouseBody.SetPosition(newPoint)
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// handle grabbing
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if raylib.IsMouseButtonPressed(raylib.MouseLeftButton) {
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result := space.PointQueryNearest(mouse, 5, grabFilter)
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if result.Shape != nil && result.Shape.Body().Mass() < cp.INFINITY {
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var nearest cp.Vector
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if result.Distance > 0 {
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nearest = result.Point
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} else {
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nearest = mouse
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}
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// create a new constraint where the mouse is to draw the body towards the mouse
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body := result.Shape.Body()
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mouseJoint = cp.NewPivotJoint2(mouseBody, body, cp.Vector{}, body.WorldToLocal(nearest))
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mouseJoint.SetMaxForce(50000)
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mouseJoint.SetErrorBias(math.Pow(1.0-0.15, 60.0))
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space.AddConstraint(mouseJoint)
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}
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} else if raylib.IsMouseButtonReleased(raylib.MouseLeftButton) && mouseJoint != nil {
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space.RemoveConstraint(mouseJoint)
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mouseJoint = nil
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}
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// perform a fixed rate physics tick
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accumulator += dt
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for accumulator >= physicsTickrate {
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space.Step(physicsTickrate)
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accumulator -= physicsTickrate
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}
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raylib.BeginDrawing()
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raylib.ClearBackground(raylib.RayWhite)
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raylib.BeginMode2D(camera)
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game.Update()
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game.Draw()
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// this is a generic way to iterate over the shapes in a space,
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// to avoid the type switch just keep a pointer to the shapes when they've been created
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space.EachShape(func(s *cp.Shape) {
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switch s.Class.(type) {
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case *cp.Segment:
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segment := s.Class.(*cp.Segment)
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a := segment.A()
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b := segment.B()
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raylib.DrawLineV(v(a), v(b), raylib.Black)
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case *cp.Circle:
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circle := s.Class.(*cp.Circle)
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pos := circle.Body().Position()
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raylib.DrawCircleV(v(pos), float32(circle.Radius()), raylib.Red)
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default:
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fmt.Println("unexpected shape", s.Class)
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}
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})
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raylib.EndMode2D()
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raylib.DrawFPS(0, 0)
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raylib.EndDrawing()
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}
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raylib.CloseWindow()
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}
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func v(v cp.Vector) raylib.Vector2 {
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return raylib.Vector2{X: float32(v.X), Y: float32(v.Y)}
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}
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