Lecture Notes: Building a Complete Platform Game Series Kickoff

Introduction

• Objective: Building a complete platform game from scratch
• End Goals: Functioning frontend, backend, menu screens, flourishes, etc.
• Tool Used: GameMaker Studio 2
• Target Audience: Beginner developers

Setting Up the Project

Creating Sprites

• Player Sprite: s_player

  • Default size: 32x32 (can be adjusted in preferences)
  • Created a green rectangle for simplicity
  • Important to set the origin to middle center (16x16) for accurate positioning

• Wall Sprite: Duplicate s_player, rename to s_wall

  • Changed color to gray
  • Ensure the origin is also set to middle center

Creating Objects

• Player Object: o_player

  • Set sprite to s_player
  • To hold all player-related game logic

• Wall Object: o_wall

  • Set sprite to s_wall
  • To represent the walls in the game

Setting Up the Room

• Default Room: room0
  • Open Room Editor and ensure instances layer is selected
• Placing Objects: Add o_player and multiple o_wall objects to shape the game area

Adding Game Logic

Introduction to Events

• Events and Actions: Game logic is based on triggering actions through events (e.g., button press, object creation)

Create Event

• Declaring Variables:
  • hsp: Horizontal speed
  • vsp: Vertical speed
  • grv: Gravity (e.g., 0.1)
  • walksp: Walk speed (e.g., 4)

Step Event

• Check for Key Presses:

  • key_left: Check if left arrow key is pressed
  • key_right: Check if right arrow key is pressed
  • key_jump: Check if space bar is pressed

• Calculate Movement:

  • Use key_left and key_right to determine direction
  • Update hsp by multiplying directional input by walksp
  • Update player coordinate X by adding hsp

Handling Collisions

• Horizontal Collision:

  • Predict collision instead of detecting post-movement
  • Use place_meeting to check for a wall collision at the predicted position
  • Adjust position to stop just before the collision

• Vertical Collision:

  • Similar logic applied for vertical movement using vsp and grv
  • Ensure player falls down due to gravity and handles vertical collisions

Gravity and Jumping

• Applying Gravity:

  • Continuously update vsp by adding gravity

• Jumping:

  • Check if player is on the floor and the jump key is pressed
  • Set vsp to a negative value to initiate the jump

Final Adjustments

• Run the Game: Set game FPS to 60 for smooth gameplay
• Debugging: If collisions or movements aren't right, re-check the conditions and logic

Conclusion

• Encouragement to Practice: Try typing in the code and use the manual to understand functions
• Acknowledgment: Kudos to supporters and viewers for their continued support and engagement in the learning process

Additional Resources

• GameMaker Manual: Middle-click on functions to access relevant documentation for deeper understanding
• Support: Consider subscribing or pledging on Patreon for more tutorials and support.