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physics code tweaks

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This commit is contained in:
Josh Deprez 2021-08-12 15:55:42 +10:00
parent 5e6bd64fef
commit 1002dc847c
1 changed files with 8 additions and 7 deletions
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15
game/aw.go
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@ -3,6 +3,7 @@ package game
import (
"encoding/gob"
"image"
"math"
"drjosh.dev/gurgle/engine"
"github.com/hajimehoshi/ebiten/v2"
@ -28,7 +29,8 @@ type Awakeman struct {
func (aw *Awakeman) Update() error {
const (
bounceDampen = 0.5
notFallingε = 0.2
restitution = -0.3
gravity = 0.3
jumpVelocity = -3.6
runVelocity = 1.4
@ -46,10 +48,9 @@ func (aw *Awakeman) Update() error {
// Capture current v_0 to use later.
ux, uy := aw.vx, aw.vy
// Standing on something?
if aw.CollidesAt(aw.Pos.Add(image.Pt(0, 1))) {
// Not falling. Let's assume aw always lands safely.
// Setting a = -v_0 gives v = v_0 - v_0 = 0.
// Has traction?
if math.Abs(aw.vy) < notFallingε && aw.CollidesAt(aw.Pos.Add(image.Pt(0, 1))) {
// Not falling.
aw.vy = 0
aw.coyoteTimer = 5
} else {
@ -95,8 +96,8 @@ func (aw *Awakeman) Update() error {
// s = (v_0 + v) / 2.
// On collision, bounce a little bit.
aw.MoveX((ux+aw.vx)/2, func() { aw.vx = -aw.vx * bounceDampen })
aw.MoveY((uy+aw.vy)/2, func() { aw.vy = -aw.vy * bounceDampen })
aw.MoveX((ux+aw.vx)/2, func() { aw.vx *= restitution })
aw.MoveY((uy+aw.vy)/2, func() { aw.vy *= restitution })
// aw.Pos is top-left corner, so add half size to get centre
aw.camera.Centre = aw.Pos.Add(aw.Size.Div(2))
return aw.Sprite.Update()