Minigame adventure map inside my blog

The Technical Blueprint: How to build the mini game - overview

To replicate the HoMM3 adventure map feel, I have to stop thinking in standard HTML/CSS and start thinking in game logic. I’ll want to use the HTML5 <canvas> element.

Here are the core systems we need to build using JavaScript:

• The Hidden Grid

HoMM3 is a tile-based game. Even though the user just sees a seamless grass texture, your JavaScript needs to divide the screen into an invisible grid (e.g., 32x32 pixel squares). Everything—the hero, the cursor, the path—operates on these grid coordinates, not raw screen pixels.

• A* Pathfinding

When you click a spot on the screen, the hero doesn’t just draw a straight line. They need to calculate the most efficient route on the grid. We will use the A (A-Star) algorithm. It is the industry standard for 2D game pathfinding. I can write this entire algorithm for you.*

• The Path Rendering (The Arrows)

When the user clicks, the A algorithm will return an array of grid coordinates (e.g., [x:1, y:2], [x:2, y:2], [x:2, y:3]). We will use JavaScript to draw the classic HoMM3 arrow graphics along those coordinates before the hero starts moving.*

• The Game Loop & Sprite Animation

*You will need a continuous JavaScript loop (using requestAnimationFrame) that constantly updates the canvas.

• The Sprite: You will need to extract the hero’s movement animation from.def files and turn them into a .png sprite sheet.

• The Movement: The JS will move the hero pixel-by-pixel towards the next tile in the path, playing the “galloping” animation, and flipping the sprite depending on if they are moving left or right.*

• Game objects, random spawning and interaction with objects

Technical TO DO list with more details about path, directions and hero move

• I think I could base it like from last path point the ‘X’. I’d take the coordinates of ‘X’ and then move by one into hero direction and set the image of the arrow based on the relation;
  next arrow - current arrow
  To figure out which arrow to draw, we have to look at the “In Vector” (where we came from) and the “Out Vector” (where we are going).
  we create a “lookup table.” We create a key based on where the path enters the tile and where it exits.
  For example, if you move right into a tile, and then move right out of it, your key is "1,0_1,0". We link that key to the specific index of the straight horizontal arrow on your sprite sheet.

• The arrows up and down are not in center. I need to fix it.

• When changing the resolution the path arrows are stuck in same position far from hero.

• I need to implement this function with relation to the hero image, it also needs to change direction depending on the path so it is correlated.

• The difficult part will be to obtain hero images from the sprite-sheet where hero images are having weird sizes about 94 x 64. It’d be perfect to have it 64 x 64.

• Also there are only assets for 5 directions of hero. I need to add 3 rest. I know two approaches to do that: Extend the image by manually inverted textures in photo editor, if hero goes in direction that there is no image, take opposite image and rotate it 180 degrees. (Do the same for every piece of animation).

• To move the hero user needs to click same grid two times. The cursor during that should change;
  default cursor, horse, and running horse.

• The hero needs to move on every tile passed with some delay like 200 ms.

• The last difficult part will be to implement animation of hero moving. So I need to put 8 images in a single move ongoing 200 ms.

Next step are described in Phases of the JS mini game