Ladders
Ready to add vertical exploration to your game world? 🪜 Ladders are one of the most iconic platformer mechanics - think Donkey Kong’s construction sites, Mega Man’s industrial levels, or any classic 2D adventure! You’re about to give your players the freedom to climb up and down through your levels, opening up incredible possibilities for level design!
Try this: Use the brown ladders to climb between platforms!
Understanding Ladder Types: Design Choices Matter!
Ladders might seem simple, but there are important design decisions to make! Let’s break down the different types:
🧱 Type A - Wall Ladders: Ladder inside a solid wall tile
- Hero can climb up/down but cannot move left/right
- Perfect for tight spaces and controlled vertical movement
- Used in games like classic Castlevania
🚶 Type B - Walkable Ladders: Ladder tile that’s also walkable
- Hero can climb up/down AND walk left/right through it
- When walking off, hero falls naturally
- Great for open level design like Mega Man
⬆️ Type C - Top-only Ladders: No ladder below, only above
- Hero can climb up but not down
- Perfect for one-way ascent areas
- Creates interesting level flow patterns
❓ Type D - Floating Ladders: Ladder that ends in mid-air
- Design choice: Can hero stand on top?
- Some games allow it, others don’t
- Consider your game’s physics consistency
Why these distinctions matter: Each type creates different gameplay feelings and level design possibilities. Choose based on how you want players to move through your world!
The Ladder Rules: Clear Gameplay Guidelines
Before we code, let’s establish crystal-clear rules for how ladders work in our game:
✅ Rule 1: Hero climbs using Up/Down arrow keys (intuitive controls!)
✅ Rule 2: Can climb UP if ladder exists at hero’s current position OR above
✅ Rule 3: Can climb DOWN if ladder exists below hero’s destination
✅ Rule 4: Can move LEFT/RIGHT off ladder if no walls block the path
✅ Rule 5: Cannot jump while climbing (climbing mode vs jumping mode)
Why these rules work:
- Simple controls that players expect
- Predictable behavior - no weird edge cases
- Smooth transitions between climbing and normal movement
- Safe navigation - prevents getting stuck in walls
These rules create the solid foundation for responsive, bug-free ladder mechanics!
Creating Ladder Tiles: Modern Implementation
Time to set up our ladder system using clean, modern JavaScript patterns:
// Tile type constants
const TILE_TYPES = {
EMPTY: 0,
SOLID: 1,
LADDER: 2,
LADDER_SOLID: 3 // Ladder you can also walk on
};
// Tile properties
const tileProperties = {
[TILE_TYPES.EMPTY]: {
solid: false,
climbable: false,
walkable: true
},
[TILE_TYPES.SOLID]: {
solid: true,
climbable: false,
walkable: false
},
[TILE_TYPES.LADDER]: {
solid: false,
climbable: true,
walkable: false // Can't walk through, only climb
},
[TILE_TYPES.LADDER_SOLID]: {
solid: false,
climbable: true,
walkable: true // Can walk AND climb
}
};
// Helper functions
function getTileProperties(tileType) {
return tileProperties[tileType] || tileProperties[TILE_TYPES.EMPTY];
}
function isClimbable(x, y) {
const tileType = getTileAt(x, y);
return getTileProperties(tileType).climbable;
}
function isSolid(x, y) {
const tileType = getTileAt(x, y);
return getTileProperties(tileType).solid;
}
Why this approach rocks:
- 🎯 Clear tile definitions with explicit properties
- 🔧 Easy to extend - just add new tile types
- 🚀 Readable code - functions that explain themselves
- 🛡️ Type safety - consistent property checking
Input Handling: Climbing Controls
Let’s implement responsive climbing controls that feel natural:
function handleClimbingInput(player, keys) {
if (player.isClimbing) {
// Climbing mode - up/down movement
if (keys['ArrowUp'] && canClimbUp(player)) {
player.y -= player.climbSpeed;
centerPlayerOnLadder(player);
} else if (keys['ArrowDown'] && canClimbDown(player)) {
player.y += player.climbSpeed;
centerPlayerOnLadder(player);
} else if (keys['ArrowLeft'] || keys['ArrowRight']) {
// Try to exit ladder horizontally
tryExitLadder(player, keys['ArrowLeft'] ? -1 : 1);
}
} else {
// Normal mode - check for ladder entry
if ((keys['ArrowUp'] || keys['ArrowDown']) && canStartClimbing(player)) {
player.isClimbing = true;
player.velocityY = 0; // Stop falling
centerPlayerOnLadder(player);
}
}
}
function centerPlayerOnLadder(player) {
// Snap player to center of ladder for clean movement
const ladderCol = Math.floor((player.x + player.width/2) / TILE_SIZE);
const ladderCenterX = ladderCol * TILE_SIZE + TILE_SIZE/2;
player.x = ladderCenterX - player.width/2;
}
function tryExitLadder(player, direction) {
const newX = player.x + direction * player.speed;
// Check all four corners for wall collision
const corners = [
{x: newX, y: player.y}, // Top-left
{x: newX + player.width, y: player.y}, // Top-right
{x: newX, y: player.y + player.height}, // Bottom-left
{x: newX + player.width, y: player.y + player.height} // Bottom-right
];
// Only exit if no corners hit walls
const canExit = corners.every(corner => !isSolid(corner.x, corner.y));
if (canExit) {
player.x = newX;
player.isClimbing = false;
}
}
Key features:
- 🎯 Auto-centering on ladders for clean movement
- 🚪 Smart exit detection prevents wall clipping
- 🎮 Separated input modes climbing vs normal movement
- ✨ Smooth transitions between movement states
Ladder Detection: Smart Climbing Logic
Now for the core climbing detection system that makes everything work smoothly:
// Check if player can start climbing at current position
function canStartClimbing(player) {
const centerX = player.x + player.width / 2;
const centerY = player.y + player.height / 2;
return isClimbable(centerX, centerY);
}
// Check if player can climb upward
function canClimbUp(player) {
const centerX = player.x + player.width / 2;
// Check current position and above
const currentClimbable = isClimbable(centerX, player.y + player.height/2);
const aboveClimbable = isClimbable(centerX, player.y - player.climbSpeed);
return currentClimbable && (aboveClimbable || isClimbable(centerX, player.y));
}
// Check if player can climb downward
function canClimbDown(player) {
const centerX = player.x + player.width / 2;
const futureY = player.y + player.height + player.climbSpeed;
// Must have ladder where we're going
return isClimbable(centerX, futureY);
}
// Main climbing physics update
function updateClimbing(player) {
if (player.isClimbing) {
// Disable gravity while climbing
player.velocityY = 0;
player.velocityX = 0;
// Check if still on a ladder
if (!canStartClimbing(player)) {
player.isClimbing = false;
// Resume normal physics
}
}
}
Visual Feedback System
Make climbing feel responsive with immediate visual feedback:
function updatePlayerVisuals(player) {
// Change appearance based on state
if (player.isClimbing) {
player.sprite.tint = 0xFFFF99; // Slight yellow tint
// Could add climbing animation here
} else {
player.sprite.tint = 0xFFFFFF; // Normal color
}
// Update sprite position
player.sprite.x = player.x;
player.sprite.y = player.y;
}
The magic happens when:
- 🎯 Player approaches ladder →
canStartClimbing()detects it - ⬆️ Up/Down pressed → Enter climbing mode
- 🧲 Auto-center → Player snaps to ladder center
- 🚫 Gravity disabled → No falling while climbing
- 🚶 Left/Right pressed → Smart exit with collision checking
- ✨ Visual feedback → Player knows they’re in climb mode
🏆 Congratulations! You’ve just implemented professional-grade ladder mechanics! Your players can now explore vertically through your levels with smooth, responsive climbing. This opens up amazing possibilities for level design - multi-story buildings, underground caverns, sky-high towers!
Next up: Time to add some challenge with enemies! Next: Stupid Enemy