How do i go about making user tap to place tiles?

Solar2D General Questions/Discussion
#21

Alternately, you could create the grid as objects, and have them be “tappable”:

local row = 3 local column = 2 local cellWidth = 32 local cellHeight = cellWidth local cell = {} local centerX = display.contentCenterX-50 local centerY = display.contentCenterY-100 local function flipSize(obj) local function objReturn() obj:setFillColor(.75,.5,.25) transition.to(obj,{time=250, alpha=1, xScale=1}) end transition.to(obj,{time=500, xScale=.1, onComplete=objReturn}) end local function handleTile(self, event) if event.phase == "ended" then flipSize(self) print("self.idx = "..self.idx.." self.idy = "..self.idy) return true end end local function createGrid() for x = 1, row do -- column cell[x] = {} for y = 1, column do --row cell[x][y] = display.newRect(x\*cellWidth, y\*cellHeight,cellWidth,cellHeight) cell[x][y].strokeWidth = 1 cell[x][y]:setStrokeColor(1) cell[x][y]:setFillColor(0) cell[x][y].x = y\*(cellWidth)+centerX cell[x][y].y = x\*(cellHeight)+centerY cell[x][y].idx = x cell[x][y].idy = y cell[x][y].tapped = false cell[x][y].type = "ground" cell[x][y].isVisible = true cell[x][y].isHitTestable = true cell[x][y].touch = handleTile cell[x][y]:addEventListener("touch", cell[x][y]) end end end createGrid()

This is a useful option if you’re using sprites, and want to optimize performance by creating all objects at level generation, rather than create them upon user interaction.

#22

Thanks all of you!

–@Alex@Panc, Is there a way of your method but just down to just bare bones? Like no shortcuts? 

–SonicX278

#23

Ok so i figured most of it out but im having trouble trying to figure out how this part works…

for x = 1, row do -- column cell[x] = {} for y = 1, column do --row

In this function.

local function createGrid() for x = 1, row do -- column cell[x] = {} for y = 1, column do --row cell[x][y] = display.newRect( x\*cellWidth, y\*cellHeight, cellWidth, cellHeight ) cell[x][y].strokeWidth = 1 cell[x][y]:setStrokeColor(1) cell[x][y]:setFillColor(0) cell[x][y].x = y\*(cellWidth)+centerX cell[x][y].y = x\*(cellHeight)+centerY cell[x][y].touch = handleTile cell[x][y]:addEventListener("touch", cell[x][y]) end end end createGrid()

Any explanation would be awesome!

Thanks!

–SonicX278

#24

Your variable naming is a bit off for the places in the tables you’re using them, but that’s just looping through the columns and then the rows within the columns. The cell[x] = {} is creating a row within the column table.

Actually, a slight performance improvement (with the variable fix) is to do it like this, to avoid extraneous references:

local columns, rows = 2, 3 local cells = {} local function createGrid() for x = 1, columns do -- columns                 local xPos = x\*cellWidth -- pre-calc the position so the multiplication is not over done                 local rowtbl = {} -- pre-create the table as variable to avoid referencing it too often cells[x] = row\_tbl for y = 1, rows do --row local rect = display.newRect( xPos, y\*cellHeight, cellWidth, cellHeight ) rect.strokeWidth = 1 rect:setStrokeColor(1) rect:setFillColor(0) rect.x = y\*(cellWidth)+centerX rect.y = x\*(cellHeight)+centerY rect.touch = handleTile rect:addEventListener("touch", cell[x][y]) rowtbl[y] = rect -- allow direct referencing of the rect when setting it's values end end end createGrid()
#25

In fact, if you were to make sure that all the cells are in the same display group, you don’t need rows and columns at all. You just place them and work out their location from their index in the group. This is fine as long as you don’t move them around in the group or add anything else to mess up their indices.

local columns, rows = 2, 3 local cells = display.newGroup() function cells:getTileAt( col, row ) return cells[ (col-1)\*columns + row ) end local function createGrid() for x = 1, columns do local xPos = x\*cellWidth-cellWidth\*.5+centerX for y = 1, rows do local yPos = y\*cellHeight-cellHeight\*.5+centerY local rect = display.newRect( cells, xPos, yPos, cellWidth, cellHeight ) rect.strokeWidth = 1 rect:setStrokeColor(1) rect:setFillColor(0) rect.touch = handleTile rect:addEventListener( "touch", rect ) rect.getColRow = getRowCol rect.index = cells.numChildren end end end createGrid()
#26

@horacebury this looks intriguing. To be honest, I never thought about optimizing my grid generation, as I assumed a 2d array rendered graphically was simple enough. I’m looking forward to poking around with this while recovering from turkey overload.

#27

I try to optimise as much as possible and after a while it becomes second nature. The reason is because table lookups can be slow in Lua, so when referencing a table on a table on a table on another table it gets to be a performance penalty. I’ve read (on the blog, etc) that where-ever possible you should use the most direct reference to something that you can. So, when iterating over items, it’s always best to grab a reference to them and their container if you’re going to do more than once thing with them. I don’t have a link to hand, but I’m sure “Lua performance” googling would surface useful info.

#28

Having said that, this is probably a good place to start: https://forums.coronalabs.com/topic/15165-tips-optimization-101/

#29

@horacebury we are of the same mind. I’ve been doing some simple testing with table iteration over the last two weeks with the same ideas in mind. Trying to squeeze every last drop out of Lua mem while rendering as many tiles as possible. I know Caleb P has made grand inroads on this front, and we are all looking forward to his tilemap shader!

I’ve been (unsuccessfully) poking around starcrunch’s relatively new table plugin. We were also talking about how hash tables are faster than arrays:

https://stackoverflow.com/questions/12020984/hash-table-why-is-it-faster-than-arrays