spritesheet idea

Comments

• skar

  April 2021 edited April 2021 Posts: 323

  you can use mesh to use a sprite sheet, although i recall reading somewhere here that mesh is going to be deprecated in C4 (why ??):

  this assumes you will have the same rectangular bounding box for each image in your sheet, if you want to handle packed sprite sheets you will need to include the data for each bounding box x,y,w, and h and figure out the values needed in setRectTex

  SpriteSheet = class()
  
  function SpriteSheet:init(i)
    self.mesh = mesh()
    self.mesh.texture = readImage(YOUR_SPRITE_SHEET)
    self.atlasCols = howManyColumns
    self.atlasRows = howManyRows
    self.frame = theStartingFrame
    self.totalFrames = howManyTotalFrames
    self.colUnit = 1 / self.atlasCols
    self.rowUnit = 1 / self.atlasRows
  end
  
  -- the draw loop, use this to loop through an animated sheet, or set
  -- the frame directly if your sheet is static
  function SpriteSheet:draw()
    self.mesh:draw()
    self.frame = self.frame + 1
    if self.frame >= self.totalFrames then
      self.frame = 1
    end
  end
  
  -- this grabs the subsection of the sprite sheet and renders it into the mesh rect
  -- it assumes all frames in the sheet have the same size bounding box (monospaced)
  function SpriteSheet:setRectTex()
    local col = self.frame % self.atlasCols
    local row = math.floor(self.frame / self.atlasCols)
    self.mesh:setRectTex(1,
      col * self.colUnit,
      (1 - self.rowUnit) - (self.rowUnit * row),
      self.colUnit,
      self.rowUnit
    )
  end
  
  -- this creates a rectangle for the mesh to render into the draw loop
  -- use this to change position, height/width and rotation
  function SpriteSheet:setRect(id, x, y, w, h, r)
    local id = id or 1
    r = (r / 360) * (math.pi*2)
    self.mesh:setRect(id, x, y, w, h, r)
  end
  
  
• Simeon Admin Mod

  April 2021 Posts: 5,781

  @skar the functionality of mesh will still exist in Codea 4, but the specific mesh related APIs will be superseded by something better
• RonJeffries Mod

  April 2021 Posts: 1,364

  interesting, @skar ... i'll have to figure that out, looks like it might do what i'm thinking. thanks!
• RonJeffries Mod

  April 2021 edited April 2021 Posts: 1,364

  @skar got it, thanks!
• RonJeffries Mod

  April 2021 Posts: 1,364

  needed an addRect. can't setRect a non-existing rect
• UberGoober

  April 2021 Posts: 1,825

  @Simeon will this break compatibility with the old code sharing posts on the forums? They are a rich source of learning...
• skar

  April 2021 edited April 2021 Posts: 323

  needed an addRect. can't setRect a non-existing rect

  @RonJeffries

  ahh my bad, i addRect in another class that i use for holding a physics body and mesh together, maybe it's better to put that into the init but maybe there was a reason i can't remember now that i didn't