Added proper taggins for gravity

internal/config/constants.go

@@ -13,10 +13,10 @@ const (
 // Physics
 const (
 	Gravity        = 1400.0
-	JumpStrength   = -480.0
+	JumpStrength   = -580.0
 	MaxFallSpeed   = 900.0
 	GroundFriction = 0.82
-	AirFriction    = 0.96
+	AirFriction    = 0.86
 )
 
 // Gameplay

internal/hero/hero.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/atridad/LilGuy/internal/config"
 	"github.com/atridad/LilGuy/internal/projectile"
+	"github.com/atridad/LilGuy/internal/world"
 )
 
 const (
@@ -49,6 +50,14 @@ const (
 	DirRight
 )
 
+// Tags
+
+type Tag int
+
+const (
+	TagGravity Tag = iota
+)
+
 // Hero state
 
 type Hero struct {
@@ -63,6 +72,8 @@ type Hero struct {
 
 	Color color.NRGBA
 
+	Tags map[Tag]bool
+
 	Stamina      float64
 	MaxStamina   float64
 	StaminaDrain float64
@@ -118,6 +129,7 @@ func New(cfg Config) *Hero {
 		Radius:        cfg.Radius,
 		Speed:         cfg.Speed,
 		Color:         cfg.Color,
+		Tags:          map[Tag]bool{TagGravity: true},
 		Stamina:       cfg.MaxStamina,
 		MaxStamina:    cfg.MaxStamina,
 		StaminaDrain:  cfg.StaminaDrain,
@@ -136,42 +148,69 @@ func New(cfg Config) *Hero {
 	}
 }
 
-func (h *Hero) Update(input Input, dt float64, bounds Bounds) {
+func (h *Hero) Update(input Input, dt float64, bounds Bounds, w *world.World) {
 	if dt > 0.1 {
 		dt = 0.1
 	}
-	h.updateMovement(input, dt, bounds)
+	h.updateMovement(input, dt, bounds, w)
 	h.updateStamina(input, dt)
 	h.updateAnimation(dt)
 }
 
 // Movement and physics
 
-func (h *Hero) updateMovement(input Input, dt float64, bounds Bounds) {
+func (h *Hero) updateMovement(input Input, dt float64, bounds Bounds, w *world.World) {
-	// apply gravity
+	if h.HasTag(TagGravity) {
 		h.VelocityY += config.Gravity * dt
+	}
 	if h.VelocityY > config.MaxFallSpeed {
 		h.VelocityY = config.MaxFallSpeed
 	}
 
 	newY := h.Y + h.VelocityY*dt
 
-	wasGrounded := h.isGrounded
-	if newY >= bounds.Ground {
-		h.Y = bounds.Ground
-		h.VelocityY = 0
-		h.isGrounded = true
-	} else {
-		h.Y = newY
 	h.isGrounded = false
+
+	if w != nil && h.VelocityY >= 0 {
+		feetX := h.X
+		var landedSurface *world.Surface
+
+		for _, s := range w.Surfaces {
+			if !s.IsWalkable() {
+				continue
 			}
 
-	if input.Jump && (h.isGrounded || (!wasGrounded && h.isGrounded)) {
+			if feetX >= s.X && feetX <= s.X+s.Width {
+				if h.Y <= s.Y && newY >= s.Y {
+					if landedSurface == nil || s.Y < landedSurface.Y {
+						landedSurface = s
+					}
+				}
+			}
+		}
+
+		if landedSurface != nil {
+			newY = landedSurface.Y
+			h.VelocityY = 0
+			h.isGrounded = true
+		}
+	}
+
+	if !h.isGrounded {
+		if newY >= bounds.Ground {
+			newY = bounds.Ground
+			h.VelocityY = 0
+			h.isGrounded = true
+		}
+	}
+
+	h.Y = newY
+
+	if input.Jump && h.isGrounded {
 		h.VelocityY = config.JumpStrength
 		h.isGrounded = false
 	}
 
-	// horizontal input
 	targetVelocityX := 0.0
 	if input.Left {
 		targetVelocityX -= h.Speed
@@ -184,7 +223,6 @@ func (h *Hero) updateMovement(input Input, dt float64, bounds Bounds) {
 
 	h.isMoving = targetVelocityX != 0
 
-	// sprinting
 	h.isSprinting = input.Sprint && h.canSprint && h.Stamina > 0 && h.isMoving
 	if h.isSprinting {
 		targetVelocityX *= config.SprintSpeedMultiplier
@@ -329,6 +367,27 @@ func (h *Hero) getCurrentSprite() *ebiten.Image {
 	return getKnightSprite(h.direction, h.isMoving, h.animFrame)
 }
 
+func (h *Hero) AddTag(tag Tag) {
+	if h.Tags == nil {
+		h.Tags = make(map[Tag]bool)
+	}
+	h.Tags[tag] = true
+}
+
+func (h *Hero) RemoveTag(tag Tag) {
+	if h.Tags == nil {
+		return
+	}
+	delete(h.Tags, tag)
+}
+
+func (h *Hero) HasTag(tag Tag) bool {
+	if h.Tags == nil {
+		return false
+	}
+	return h.Tags[tag]
+}
+
 func (h *Hero) GetDirection() Direction {
 	return h.direction
 }

internal/maps/plains.go

@@ -13,13 +13,48 @@ func CreatePlains(screenWidth, screenHeight float64) *Map {
 	m.BackgroundColor = color.NRGBA{R: 135, G: 206, B: 235, A: 255}
 
 	// ground surface
+	groundColor := color.NRGBA{R: 34, G: 139, B: 34, A: 255}
 	m.World.AddSurface(&world.Surface{
 		X:      0,
 		Y:      screenHeight - config.GroundHeight,
 		Width:  screenWidth,
 		Height: config.GroundHeight,
 		Tag:    world.TagGround,
-		Color:  color.NRGBA{R: 34, G: 139, B: 34, A: 255},
+		Color:  groundColor,
+	})
+
+	// Platforms
+	// Use ground color by default as requested
+	platformColor := groundColor
+
+	// Platform 1: Low left
+	m.World.AddSurface(&world.Surface{
+		X:      100,
+		Y:      screenHeight - 120,
+		Width:  150,
+		Height: 20,
+		Tag:    world.TagPlatform,
+		Color:  platformColor,
+	})
+
+	// Platform 2: Mid center
+	m.World.AddSurface(&world.Surface{
+		X:      350,
+		Y:      screenHeight - 200,
+		Width:  200,
+		Height: 20,
+		Tag:    world.TagPlatform,
+		Color:  platformColor,
+	})
+
+	// Platform 3: High right
+	m.World.AddSurface(&world.Surface{
+		X:      650,
+		Y:      screenHeight - 280,
+		Width:  150,
+		Height: 20,
+		Tag:    world.TagPlatform,
+		Color:  platformColor,
 	})
 
 	// left portal to desert

internal/screens/gameplay.go

@@ -119,7 +119,7 @@ func (g *GameplayScreen) Update(input GameplayInput, delta time.Duration) {
 		Right:  input.Right,
 		Jump:   input.Jump,
 		Sprint: input.Sprint,
-	}, dt, g.bounds)
+	}, dt, g.bounds, g.world)
 
 	if input.Shoot {
 		direction := 1.0