Drag Drop am I doing it right?

[Rob.m]

Hi all, and thanks everyone for the help.

I now have a basic drag and drop. It's NOT great but t's a start.

Any pointers would be great before I move further into learning this code.

The code is below but probably wont work without the tiles image so I have also attached the .love file.

DragAndDrop.love

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Code: Select all

function love.load()
  mouse_dx = nil
  mouse_dy = nil
  mouse_down = false
  mouse_quad = nil
  tiles = love.graphics.newImage("tiles.png") -- a 64px*64px canvas with 16 x 16px*16px tiles arragnged as 4*4 tiles
  quads = {} -- 16 quads of 16px x 16px
  local x
  local y
  for y = 0, 3 do
    for x = 0, 3 do
      quads[y * 4 + x + 1] = love.graphics.newQuad(x * 16, y * 16 , 16, 16, 64, 64)
    end
  end
  display = {} -- 50 tiles x 37.5 tiles of 16px x 16px for screen res 800px x 600px
  for y = 0, 37 do
    for x = 0, 49 do
      display[y * 50 + x + 1] = quads[1] -- set the quad to the default background quad
      if x > 16 and x < 33 and y > 9 and y < 27 then -- if in the droppable area
        display[y * 50 + x + 1] = quads[2]  -- set the quad to the grid quad
      end
      if x > 45 and x < 48 and y > 13 and y < 22 then -- if in the pickup area
        display[y * 50 + x + 1] = quads[(y - 14) * 2 + x - 45] -- set the quad to one of the sixteen
      end      
    end
  end
end




function love.update()
end




function love.draw()
  love.graphics.draw(tiles, 0, 0, 0, 1, 1, 0, 0, 0, 0)
  local x
  local y
  for y = 0, 37 do
    for x = 0, 49 do
      love.graphics.drawq(tiles, display[y * 50 + x + 1], x * 16, y * 16 , 0, 1, 1, 0, 0, 0, 0)
    end
  end
  if mouse_down == true then
    love.graphics.drawq(tiles, mouse_quad, love.mouse.getX() + mouse_dx, love.mouse.getY() + mouse_dy, 0, 1, 1, 0, 0, 0, 0)
  end
end


function love.mousepressed(x, y, button)
  if button == 'l' then
    local tile_x = math.floor(x / 16)
    local tile_y = math.floor(y / 16)
    if tile_x > 45 and tile_x < 48 and tile_y > 13 and tile_y < 22 then -- if in the pickup area
      mouse_quad = quads[(tile_y - 14) * 2 + tile_x - 45]
      mouse_dx = tile_x * 16 - x
      mouse_dy = tile_y * 16 - y
      mouse_down = true
    end
  end
end


function love.mousereleased(x, y, button)
  if button == 'l' and mouse_down == true then
    mouse_down = false
    local tile_x = math.floor(x / 16)
    local tile_y = math.floor(y / 16)
    if tile_x > 16 and tile_x < 33 and tile_y > 9 and tile_y < 27 then -- if in the droppable area
      display[tile_y * 50 + tile_x + 1] = mouse_quad -- drop the quad into the display grid
    end
  end
end

[micha]

I now have a basic drag and drop. It's NOT great but t's a start.

Why are you saying that? It works perfectly on my computer.
It is not finished though. The next thing to add, I guess, is draging the tiles, that are in the grid already (player makes a mistake, wants to correct a misplaced tile)