So far we have the makings of a game but, there are more than a few that need to be taken care of. For example, the buttons do not show the energy cost. This makes it hard to play and test, since it’s hard to tell what the cost is for defenses.
Groups as layers again
The buttons that I had created earlier were simple shapes. To show both text and a shape we need to create a group and add both elements to the group. Groups in Corona have all of the common display properties available to other display objects.
To make this work out I created a group for each button and used this to replace the original shape I had used for the button. Then I added the original rounded rectangle to the group. Then created a new Text shape and added that to the new group also.
I need to keep a reference to the rounded rectangle shape and text field. So I added properties to the group to hold these.
From here I retooled the rest of the script so all of the properties that had been attached to the button shape were now attached to the button_group. I also inserted the button_group into the defense_button_array in place of the original button shape. I also added the button_group into the control_group.
To get the costs to chose up in the text field I needed to get the cost from the defense_type_array for the current defense type and set it as the text of button_text.
Last I needed to adjust the positions of all three objects: button_group, button, and button_text.
local function make_defense_buttons() for i = 1, #defense_type_array, 1 do local button_group = display.newGroup() -- Make a group to hold all button elements local button = display.newRoundedRect( 0, 0, 40, 40, 6 ) local r = 255 * ( i / #defense_type_array ) button:setFillColor( r, 0, 0 ) button:setStrokeColor( 255, 255, 255 ) defense_type_array[i].red = r local button_text = display.newText( "0", 0, 0, native.systemFontBold, 14 ) -- make a text field button_text.text = defense_type_array[i].cost -- Display the cost button_text.x = 20 -- Set the position of the label button_text.y = 20 -- Set the position of the label button_group:insert( button ) -- Add button shape to group button_group:insert( button_text ) -- Add text to group button_group.shape = button -- add button shape as a property to group button_group.label = button_text -- add button text as property of group -- Assign these properties to button group button_group.index = i button_group.x = display.contentWidth - 45 -- adjust the position button_group.y = 40 + ( i * 50 ) button_group:addEventListener( "touch", touch_defense_button ) table.insert(defense_button_array, button_group ) -- Add button group to array control_group:insert( button_group ) -- add button group to control group end end
The select_defense_button() function needs a little work also. This function needs to now set the stroke of the shape rather than the button. After the changes above the button will be a group rather than a shape.
local function select_defense_button() for i = 1, #defense_button_array, 1 do local button = defense_button_array[i] if button.index == current_defense_type then button.shape.strokeWidth = 3 -- set the stroke of the shape else button.shape.strokeWidth = 0 -- set the stroke of the shape end end end
Showing disabled buttons
If a defense is not available to a player, due to not having enough energy to meet the cost, it should display as disabled. For this example I’ll make buttons that are disabled appear transparent. When a button is available it will be opaque.
Add a new function to handle this above touch_defense_button(). This new function will loop through each button in the defense_button_array and compare it’s cost to the current energy value and set it’s alpha accordingly.
-- *** Add a new function to enable and disable buttons based on energy available local function enable_disable_buttons() for i = 1, #defense_button_array,1 do local button = defense_button_array[i] local cost = button.cost if cost < energy then button.enabled = true button.alpha = 1.0 else button.enabled = false button.alpha = 0.5 end end end
To set up the initial state for these buttons we should call on this function when the game begins. Place a call below make_defense_buttons().
enable_disable_buttons()
Last, when the energy value changes we need to update the buttons to show a new state. Find the energy_recharge() function and add a call to enable_disable_buttons() there.
local function energy_recharge() energy = energy + ENERGY_RECHARGE_RATE enable_disable_buttons() -- *** Update buttons update_energy() end>
This works here but might need to be rethought if the recharge rate were slower.
Here's a full listing of the code
-----------------------------------------------------------------------------------------
--
-- main.lua
--
-----------------------------------------------------------------------------------------
-- The goal of this example will be to turn enemies, defense and buttons into
-- group objects that contain more than one element.
-- The
display.setStatusBar( display.HiddenStatusBar )
local TILE_ROWS = 9
local TILE_COLS = 5
local TILE_SIZE = 48
local TILE_MARGIN = 1
local BULLET_SPEED = 1000 / 400
local ALIEN_SPEED = 1000 / 20
local ENERGY_RECHARGE_RATE = 1
local ENERGY_TIMER_TIME = 150
local alien_timer
local energy_timer
local energy = 0
local current_defense_type = 1
local energy_text
local alien_target_y = ( TILE_SIZE + TILE_MARGIN ) * TILE_ROWS
local defense_array = {}
local alien_array = {}
local bullet_array = {}
local defense_type_array = {
{name="Standard", rof=1000, damage=1, cost=50},
{name="Rapid", rof=800, damage=1, cost=75},
{name="Heavy", rof=2000, damage=3, cost=100},
{name="Stun", rof=1200, damage=0.5, cost=80}
}
local defense_button_array = {}
local game_group = display.newGroup()
local defense_group = display.newGroup()
local alien_group = display.newGroup()
local tile_group = display.newGroup()
local control_group = display.newGroup()
game_group:insert( tile_group )
game_group:insert( defense_group )
game_group:insert( alien_group )
local function select_defense_button()
for i = 1, #defense_button_array, 1 do
local button = defense_button_array[i]
if button.index == current_defense_type then
button.shape.strokeWidth = 3 -- set the stroke of the shape
else
button.shape.strokeWidth = 0 -- set the stroke of the shape
end
end
end
-- *** Add a new function to enable and disable buttons based on energy available
local function enable_disable_buttons()
for i = 1, #defense_button_array,1 do
local button = defense_button_array[i]
local cost = button.cost
if cost < energy then
button.enabled = true
button.alpha = 1.0
else
button.enabled = false
button.alpha = 0.5
end
end
end
local function touch_defense_button( event )
local button = event.target
current_defense_type = button.index
select_defense_button()
end
local function make_defense_buttons()
for i = 1, #defense_type_array, 1 do
local button_group = display.newGroup() -- Make a group to hold all button elements
local button = display.newRoundedRect( 0, 0, 40, 40, 6 )
local r = 255 * ( i / #defense_type_array )
button:setFillColor( r, 0, 0 )
button:setStrokeColor( 255, 255, 255 )
defense_type_array[i].red = r
button_group.cost = defense_type_array[i].cost -- *** add cost
button_group.enabled = false -- *** add a property to mark this button as enabled
local button_text = display.newText( "0", 0, 0, native.systemFontBold, 14 ) -- make a text field
button_text.text = defense_type_array[i].cost -- Display the cost
button_text.x = 20 -- Set the position of the label
button_text.y = 20 -- Set the position of the label
button_group:insert( button ) -- Add button shape to group
button_group:insert( button_text ) -- Add text to group
button_group.shape = button -- add button shape as a property to group
button_group.label = button_text -- add button text as property of group
-- Assign these properties to button group
button_group.index = i
button_group.x = display.contentWidth - 45 -- adjust the position
button_group.y = 40 + ( i * 50 )
button_group:addEventListener( "touch", touch_defense_button )
table.insert(defense_button_array, button_group ) -- Add button group to array
control_group:insert( button_group ) -- add button group to control group
end
end
make_defense_buttons()
select_defense_button()
enable_disable_buttons() -- *** Call this to initialize buttons
energy_text = display.newText( energy, 0, 0, native.systemFont, 16 )
control_group:insert( energy_text )
energy_text:setTextColor( 0, 255, 0 )
energy_text.x = 300
energy_text.y = 40
local function update_energy()
energy_text.text = energy
end
local function energy_recharge()
energy = energy + ENERGY_RECHARGE_RATE
enable_disable_buttons() -- *** Update buttons
update_energy()
end
energy_timer = timer.performWithDelay( ENERGY_TIMER_TIME, energy_recharge, -1 )
local function remove_bullet( bullet )
local index = table.indexOf( bullet_array, bullet )
transition.cancel( bullet.transition )
table.remove( bullet_array, index )
display.remove( bullet )
end
local function make_bullet( x, y )
local bullet = display.newCircle( 0, 0, 5 )
bullet:setFillColor( 0, 0, 0 )
bullet.x = x
bullet.y = y
table.insert( bullet_array, bullet )
local bt = y * BULLET_SPEED
bullet.transition = transition.to( bullet, {y=0, time=bt, onComplete=remove_bullet} )
return bullet
end
local function defense_defend( defense )
for i = 1, #alien_array, 1 do
local alien = alien_array[i]
if alien.col == defense.col then
local bullet = make_bullet( defense.x, defense.y )
bullet.damage = defense.damage
bullet.defense_name = defense.defense_name
break
end
end
end
local function remove_defense( defense )
local index = table.indexOf( defense_array, defense )
timer.cancel( defense.timer )
table.remove( defense_array, index )
display.remove( defense )
end
local function make_defense( x, y )
local defense = display.newRect( 0, 0, 32, 32 )
defense.rof = defense_type_array[current_defense_type].rof
defense.damage = defense_type_array[current_defense_type].damage
defense.defense_name = defense_type_array[current_defense_type].name
defense.red = defense_type_array[current_defense_type].red
defense:setFillColor( defense.red, 0, 0 )
defense_group:insert( defense )
defense.x = x
defense.y = y
table.insert( defense_array, defense )
defense.timer = timer.performWithDelay( defense.rof, function() defense_defend( defense ) end, -1 )
return defense
end
local function touch_tile( event )
local phase = event.phase
if phase == "began" then
local tile = event.target
local tile_x = tile.x
local tile_y = tile.y
local cost = defense_type_array[current_defense_type].cost
if energy >= cost then
energy = energy - cost
local defense = make_defense( tile_x, tile_y )
defense.col = tile.col
end
end
end
local function make_grid()
for row = 1, TILE_ROWS, 1 do
for col = 1, TILE_COLS, 1 do
local tile = display.newRect( 0, 0, TILE_SIZE, TILE_SIZE )
tile.x = ( TILE_SIZE + TILE_MARGIN ) * col
tile.y = ( TILE_SIZE + TILE_MARGIN ) * row
tile.col = col
tile.has_defense = false
tile:addEventListener( "touch", touch_tile )
tile_group:insert( tile )
end
end
end
local function remove_alien( alien )
local index = table.indexOf( alien_array, alien )
transition.cancel( alien.transition )
table.remove( alien_array, index )
display.remove( alien )
end
local function make_alien()
local alien = display.newRect( 0, 0, 32, 32 )
alien:setFillColor( 0, 200, 0 )
local col = math.random( 1, TILE_COLS )
alien.col = col
alien.x = col * ( TILE_SIZE + TILE_MARGIN )
alien.y = 0
alien.life = 5
local t = alien_target_y * ALIEN_SPEED
alien.transition = transition.to( alien, {y=alien_target_y, time=t, onComplete=remove_alien} )
alien_group:insert( alien )
table.insert( alien_array, alien )
end
local function hit_test( x, y, bounds )
return x > bounds.xMin
and x < bounds.xMax
and y > bounds.yMin
and y < bounds.yMax
end
local function hit_test_bounds( bounds1, bounds2 )
return bounds1.xMin < bounds2.xMax
and bounds1.xMax > bounds2.xMin
and bounds1.yMin < bounds2.yMax
and bounds1.yMax > bounds2.yMin
end
local function check_bullets()
for b = 1, #bullet_array, 1 do
local bullet = bullet_array[b]
if b > #bullet_array then
return
end
for a = 1, #alien_array, 1 do
local alien = alien_array[a]
if hit_test( bullet.x, bullet.y, alien.contentBounds ) then
if alien.life > 0 then
alien.life = alien.life - bullet.damage
local defense_name = bullet.defense_name
if defense_name == "Stun" then
transition.cancel( alien.transition )
local t = ( alien_target_y - alien.y ) * ALIEN_SPEED
alien.transition = transition.to( alien, { y=alien_target_y,
time=t,
delay=300,
onComplete=remove_alien } )
end
else
remove_alien( alien )
end
remove_bullet( bullet )
break
end
end
end
end
local function check_enemies()
for a = 1, #alien_array, 1 do
local alien = alien_array[a]
for d = 1, #defense_array, 1 do
local defense = defense_array[d]
if hit_test_bounds( alien.contentBounds, defense.contentBounds ) then
remove_defense( defense )
break
end
end
end
end
local function on_enterframe( event )
check_bullets()
check_enemies()
end
Runtime:addEventListener( "enterFrame", on_enterframe )
make_grid()
alien_timer = timer.performWithDelay( 5300, make_alien, -1 )
-------------------------------------------------------------------------------------
local memory_text = display.newText( "Hello", 5, 5, native.systemFont, 16 )
memory_text:setTextColor( 255, 0, 0 )
memory_text.x = display.contentCenterX
local monitorMem = function()
collectgarbage()
local textMem = system.getInfo( "textureMemoryUsed" ) / 1000000
memory_text.text = "Mem:"..collectgarbage("count") .. " tex:".. textMem
end
Runtime:addEventListener( "enterFrame", monitorMem )