Some adjustments

cloth.go

@@ -10,7 +10,7 @@ import (
 	"gioui.org/op/paint"
 )
 
-const lineWidth = 0.8
+const lineWidth = 0.6
 
 type Cloth struct {
 	constraints   []*Constraint
@@ -25,13 +25,12 @@ type Cloth struct {
 
 // NewCloth creates a new cloth which dimension is calculated based on
 // the application window width and height and the spacing between the sticks.
-func NewCloth(width, height, spacing int, friction float64, col color.NRGBA) *Cloth {
+func NewCloth(width, height, spacing int, col color.NRGBA) *Cloth {
 	return &Cloth{
-		width:    width,
-		height:   height,
-		spacing:  spacing,
-		friction: friction,
-		color:    col,
+		width:   width,
+		height:  height,
+		spacing: spacing,
+		color:   col,
 	}
 }
 
@@ -67,7 +66,7 @@ func (c *Cloth) Init(posX, posY int, hud *Hud) {
 				c.constraints = append(c.constraints, constraint)
 			}
 
-			pinX := x % (clothX / 9)
+			pinX := x % (clothX / 10)
 			if y == 0 && pinX == 0 {
 				particle.pinX = true
 			}
@@ -81,7 +80,7 @@ func (c *Cloth) Init(posX, posY int, hud *Hud) {
 // Update updates the cloth particles invoked on each frame event of the Gio internal window calls.
 // The cloth contraints are solved by using the Verlet integration formulas.
 func (cloth *Cloth) Update(gtx layout.Context, mouse *Mouse, hud *Hud, dt float64) {
-	dragForce := float32(mouse.getForce() * 0.25)
+	dragForce := float32(mouse.getForce() * 0.1)
 	clothColor := color.NRGBA{R: 0x55, A: 0xff}
 	// Convert the RGB color to HSL based on the applied force over the mouse focus area.
 	col := LinearFromSRGB(clothColor).HSLA().Lighten(dragForce).RGBA().SRGB()

hud.go

@@ -74,7 +74,7 @@ func NewHud() *Hud {
 
 	sliders := []slider{
 		{title: "Drag force", min: 1.1, value: 2, max: 15},
-		{title: "Gravity force", min: 100, value: 250, max: 500},
+		{title: "Gravity", min: 100, value: 250, max: 500},
 		{title: "Elasticity", min: 10, value: 30, max: 50},
 		{title: "Stiffness", min: 0.95, value: 0.98, max: 0.99},
 		{title: "Tear distance", min: 5, value: 20, max: 80},
@@ -87,8 +87,8 @@ func NewHud() *Hud {
 		{"F1": "Toggle the quick help panel"},
 		{"Space": "Redraw the cloth"},
 		{"Right click": "Tear the cloth at mouse position"},
-		{"Click & hold": "Increase the mouse pressure"},
-		{"Scroll Up/Down": "Change the mouse focus area"},
+		{"Click & hold": "Increase cloth destruction"},
+		{"Scroll Up/Down": "Increase/decrease cloth destruction area"},
 		{"Ctrl+click": "Pin the cloth particle at mouse position"},
 	}
 

main.go

@@ -34,8 +34,8 @@ const (
 	windowSizeX = 1280
 	windowSizeY = 820
 
-	defaultWindowWidth  = 940
-	defaultWindowHeigth = 580
+	defaultWindowWidth  = 1024
+	defaultWindowHeigth = 640
 )
 
 var (
@@ -49,6 +49,8 @@ var (
 	clothW int
 	clothH int
 
+	clothSpacing = 6
+
 	// Gio Ops related variables
 	ops          op.Ops
 	initTime     time.Time
@@ -132,11 +134,17 @@ func loop(w *app.Window) error {
 					pprof.StartCPUProfile(file)
 				}
 
-				// Cloth is not initialized yet. Initialize it.
+				// Cloth is not initialized yet.
 				if cloth == nil {
 					clothW = gtx.Dp(unit.Dp(windowWidth))
 					clothH = gtx.Dp(unit.Dp(windowHeight) * 0.33)
-					cloth = NewCloth(clothW, clothH, 12, 0.98, defaultColor)
+					clothSpacing = func() int { // different cloth spacing for hi-res devices.
+						if clothW <= windowWidth {
+							return clothSpacing
+						}
+						return 2 * clothSpacing
+					}()
+					cloth = NewCloth(clothW, clothH, clothSpacing, defaultColor)
 
 					width := gtx.Constraints.Max.X
 					height := gtx.Constraints.Max.Y
@@ -152,6 +160,8 @@ func loop(w *app.Window) error {
 					Keys: key.NameEscape + "|" + key.NameCtrl + "|" + key.NameAlt + "|" + key.NameSpace + "|" + key.NameF1,
 				}.Add(gtx.Ops)
 
+				pointer.CursorPointer.Add(gtx.Ops)
+
 				if mouse.getLeftButton() {
 					deltaTime = time.Since(initTime)
 					mouse.setForce(deltaTime.Seconds() * 5)