Touching on the particular sprite from the spritesheet

Question

I want to click on the particular sprite from the sprite sheet. For instance i have fruits sprite sheet i want to click on the particular fruit.

Thanks, Jubin Mehta

Answer 1

A general solution would be:

1. Get the cursor position.

2. Transform the position into the tiles local coordinate space.

   pixelPositionX = cursorPositionX - (tilePositionInWorldX - screenPositionX)

   pixelPositionY = cursorPositionY - (tilePositionInWorldY - screenPositionY)

3. Find out if the position is inside the tile.

   tilePositionOnSpritesheetX < pixelpositionX < tilePositionOnSpritesheetX + tileSizeX

   tilePositionOnSpritesheetY < pixelpositionY < tilePositionOnSpritesheetY + tileSizeY

4. If it is, check if the alpha value of the pixel at that position is over a certain treshold.

Step 4 is optional, without it, you're checking against the tiles bounding rectangle, with it, clicking is pixel perfect.

Please note that all positions and sizes are assumed to be in pixels.