Collision with spawnProjectile does not collide with static objects

[underlabs]

Hi All,

I’ve been loving Corona SDK for it’s ease of use of lua and the features Corona hands out of the box.

I’ve been blocked for a while on this scene where the Projectile (ball) after it releasing an elastic band does not collide with static objects.

This is the Ball Class:
[lua]module(…, package.seeall)
– Pass state reference
state = {};
– Bullet starts off in-active
ready = false;
– Pass audio references
shot = {};
band_stretch = {};

function newProjectile()

– Import easing plugin
local easingx = require(“easing”);

– Bullet properties
local bun_bullet = {
name = “pepsiBall”, – bun
type = “bullet”,
density=0.8,
friction=0.3,
bounce=0.6,
size = 49,
rotation = 30
}

– Init bullet
local bullet = display.newImage(“images/ammo/” … bun_bullet.name … “.png”);
– Place bullet
bullet.x = 170; bullet.y = _H + 20;
– Set up physical properties
physics.addBody(bullet, “kinematic”, {density=bun_bullet.density, friction=bun_bullet.friction, bounce=bun_bullet.bounce, radius=bun_bullet.size});

bullet.linearDamping = 0.3;
bullet.angularDamping = 0.8;
bullet.isBullet = true;
bullet.isSensor = true;
– Transition the bullet into position each time it’s spawned
transition.to(bullet, {time=600, y=_H - 140, transition = easingx.easeOutElastic});

return bullet;

end[/lua]

and this is the main scene
[lua]local storyboard = require( “storyboard” )
local scene = storyboard.newScene()

local ui = require “scripts.lib.ui”
local radlib = require “scripts.lib.radlib”

local physics = require “physics”
physics.start()
physics.setGravity(9.81) – 9.81 m/s*s in the positive y direction
physics.setScale(80) – 80 pixels per meter
physics.setDrawMode(“normal”)

local _WCenter = display.contentWidth/2;
local _HCenter = display.contentHeight/2;

local _W = display.contentWidth;
local _H = display.contentHeight + 20;

---

– BEGINNING OF YOUR IMPLEMENTATION

function scene:createScene( event )
local screenGroup = self.view
– Create the bounds of the “arena”
local background = display.newImage( “assets/playground.png” )
background.x = _WCenter;
background.y = _HCenter;

– Screen borders
local floor = display.newRect(_W, 0, 1, _H)
local lWall = display.newRect(0, _H, _W, 1)
local rWall = display.newRect(0, -1, _W, 1)
local ceiling = display.newRect(-1, 0, 1, _H)
screenGroup:insert(background)
screenGroup:insert(floor)
screenGroup:insert(lWall)
screenGroup:insert(rWall)
screenGroup:insert(ceiling)

staticMaterial = {density=2, friction=.3, bounce=.4}
physics.addBody(floor, “static”, staticMaterial)
physics.addBody(lWall, “static”, staticMaterial)
physics.addBody(rWall, “static”, staticMaterial)
physics.addBody(ceiling, “static”, staticMaterial)
–BALL
local ball = display.newImage( “assets/pepsiBall.png”)
ball.y = 150

physics.addBody(ball, {density=.8, friction=.3, bounce=.6, radius=49})
screenGroup:insert(ball)

– SCORE
local score = display.newText(“Score: 0”, _WCenter + 60, 5)
score:setTextColor(255, 255, 255, 255)
score.size = 25
screenGroup:insert(score)
– End step 2

local speedX = 0
local speedY = 0
local prevTime = 0
local prevX = 0
local prevY = 0

– A basic function for dragging physics objects
local function drag( event )
local ball = event.target

local phase = event.phase
if “began” == phase then
display.getCurrentStage():setFocus( ball )

– Store initial position
ball.x0 = event.x - ball.x
ball.y0 = event.y - ball.y

– Make body type temporarily “kinematic” (to avoid gravitional forces)
event.target.bodyType = “kinematic”

– Stop current motion, if any
event.target:setLinearVelocity( 0, 0 )
event.target.angularVelocity = 0

else
if “moved” == phase then
ball.x = event.x - ball.x0
ball.y = event.y - ball.y0
elseif “ended” == phase or “cancelled” == phase then
display.getCurrentStage():setFocus( nil )
event.target.bodyType = “dynamic”
ball:setLinearVelocity(speedX, speedY)
end
end

– Stop further propagation of touch event!
return true
end

function trackVelocity(event)
local timePassed = event.time - prevTime
prevTime = prevTime + timePassed
speedX = (ball.x - prevX)/(timePassed/1000)
speedY = (ball.y - prevY)/(timePassed/1000)

prevX = ball.x
prevY = ball.y
end

Runtime:addEventListener(“enterFrame”, trackVelocity)
ball:addEventListener(“touch”, drag)

–Create the hoop and scoring mechanism
local rimNet = display.newRect(_WCenter - 100, 40, 190, 9)
rimNet:setFillColor(255, 255, 255)
rimNet.alpha = 0.8
screenGroup:insert(rimNet)

local leftBorder = display.newRect(_WCenter - 100,30, 9, 25)
leftBorder:setFillColor(89,58,35)
screenGroup:insert(leftBorder)

local rightBorder = display.newRect(_WCenter + 85,30, 9, 25)
rightBorder:setFillColor(89,58,35)
screenGroup:insert(rightBorder)

physics.addBody(leftBorder, “static”, staticMaterial)
physics.addBody(rightBorder, “static”, staticMaterial)

scoreCtr = 0
local lastGoalTime = 1000

function monitorScore(event)
if event.time - lastGoalTime > 500 then
if ball.x > _WCenter - 100 and ball.x < _WCenter + 85 and ball.y < 65 then
scoreCtr = scoreCtr + 1
print(score)
lastGoalTime = event.time
score.text = "Score: " … scoreCtr
if scoreCtr == 1 then
local infoMessage = display.newText(“Mabrouk, one more”, _WCenter, _HCenter)
infoMessage:setTextColor(255, 255, 255, 255)
infoMessage.size = 25
transition.to( infoMessage, { time=2000, alpha=0, x=(_WCenter-50), y=(_HCenter-50) } )
screenGroup:insert(infoMessage)
elseif scoreCtr == 2 then
Runtime:removeEventListener(“enterFrame”, trackVelocity)
Runtime:removeEventListener(“enterFrame”, monitorScore)
storyboard.gotoScene( “play2” )
end
end
end
end

Runtime:addEventListener(“enterFrame”, monitorScore)

end

function scene:enterScene( event )
print(“Play loaded…”)

storyboard.removeAll()
end

function scene:exitScene( event )
end

function scene:destroyScene( event )
end

---

– END OF YOUR IMPLEMENTATION

–
– “createScene” event is dispatched if scene’s view does not exist
scene:addEventListener( “createScene”, scene )

– “enterScene” event is dispatched whenever scene transition has finished
scene:addEventListener( “enterScene”, scene )

– “exitScene” event is dispatched before next scene’s transition begins
scene:addEventListener( “exitScene”, scene )

– “destroyScene” event is dispatched before view is unloaded, which can be
– automatically unloaded in low memory situations, or explicitly via a call to
– storyboard.purgeScene() or storyboard.removeScene().
scene:addEventListener( “destroyScene”, scene )

return scene[/lua]

If you run this code, you’ll notice once you e.phase ends, I change t.bodyType = “dynamic”; and yet it still dosen’t collide. Any thoughts, or game logic I’m missing? [import]uid: 141821 topic_id: 29622 reply_id: 329622[/import]

[underlabs]

Ignore previous Scene, This is actually the right version for the Scene Class:
[lua]local storyboard = require( “storyboard” )
local scene = storyboard.newScene()

– Global vars set up
_W = display.contentWidth;
_H = display.contentHeight;

– Imports
local movieclip = require(“movieclip”);
local physics = require(“physics”);
physics.start();

m = {}
m.random = math.random;

local state = display.newGroup(); – States where all

– Import projectile classes
local projectile = require(“projectile”);

– Variables setup
local projectiles_container = nil; – Where the Balls are!
local force_multiplier = 4;
local velocity = m.random(50,100);

– Visible groups setup
local background = display.newGroup();
local slingshot_container = display.newGroup();

– Build the catapult
– Front strut
local slingshot_strut_front = display.newImage(“images/slingshot_strut_front.png”,true);
slingshot_strut_front.x = 210;
slingshot_strut_front.y = _H - 25;
– Back strut
local slingshot_strut_back = display.newImage(“images/slingshot_strut_back.png”,true);
slingshot_strut_back.x = 210;
slingshot_strut_back.y = _H - 25;

– Move catapult up
slingshot_container.y = -25;

local state_value = nil;

– Audio
local shot = audio.loadSound(“sounds/band-release.aif”);
local band_stretch = audio.loadSound(“sounds/stretch-1.aif”);

– Transfer variables to the projectile classes
projectile.shot = shot;
projectile.band_stretch = band_stretch;

– Background image
local bg_image = display.newImage(“assets/playground.png”,true);
background:insert(bg_image);

local rimNet = display.newRect((_W/2), 40, 90, 9)
rimNet:setFillColor(255, 255, 255)
rimNet.alpha = 0.8

local leftBorder = display.newRect((_W/2)-5, 35, 9, 25)
leftBorder:setFillColor(89,58,35)

local rightBorder = display.newRect((_W/2)+90, 35, 9, 25)
rightBorder:setFillColor(89,58,35)

physics.addBody(leftBorder, “static”, staticMaterial)
physics.addBody(rightBorder, “static”, staticMaterial)

---

– BEGINNING OF YOUR IMPLEMENTATION

function scene:createScene( event )
local screenGroup = self.view
screenGroup:insert(background)
screenGroup:insert(slingshot_container)
screenGroup:insert(rimNet)
screenGroup:insert(leftBorder)
screenGroup:insert(rightBorder)
end

local function projectileTouchListener(e)
– The current projectile on screen
local t = e.target;
– If the projectile is ‘ready’ to be used
if(t.ready) then
– if the touch event has started…
if(e.phase == “began”) then
– Play the band stretch
audio.play(band_stretch);
– Set the stage focus to the touched projectile
display.getCurrentStage():setFocus( t );
t.isFocus = true;
t.bodyType = “kinematic”;

– Stop current physics motion, if any
t:setLinearVelocity(0,0);
t.angularVelocity = 0;

– Init the elastic band.
local myLine = nil;
local myLineBack = nil;

– Bunny eyes animation
–bunny_eyes:stopAtFrame(2);

– If the target of the touch event is the focus…
elseif(t.isFocus) then
– If the target of the touch event moves…
if(e.phase == “moved”) then

– If the band exists… refresh the drawing of the line on the stage.
if(myLine) then
myLine.parent:remove(myLine); – erase previous line
myLineBack.parent:remove(myLineBack); – erase previous line
myLine = nil;
myLineBack = nil;
end

– If the projectile is in the top left position
if(t.x < 105 and t.y < _H - 165)then
myLineBack = display.newLine(t.x - 30, t.y, 196, _H - 165);
myLine = display.newLine(t.x - 30, t.y, 120, _H - 152);
– If the projectile is in the top right position
elseif(t.x > 105 and t.y < _H - 165)then
myLineBack = display.newLine(t.x + 10, t.y - 25, 196, _H - 165);
myLine = display.newLine(t.x + 10, t.y - 25, 120, _H - 152);
– If the projectile is in the bottom left position
elseif(t.x < 105 and t.y > _H - 165)then
myLineBack = display.newLine(t.x - 25, t.y + 20, 196, _H - 165);
myLine = display.newLine(t.x - 25, t.y + 20, 120, _H - 152);
– If the projectile is in the bottom right position
elseif(t.x > 105 and t.y > _H - 165)then
myLineBack = display.newLine(t.x - 15, t.y + 30, 196, _H - 165);
myLine = display.newLine(t.x - 15, t.y + 30, 120, _H - 152);
else
– Default position (just in case).
myLineBack = display.newLine(t.x - 25, t.y, 196, _H - 165);
myLine = display.newLine(t.x - 25, t.y, 120, _H - 152);
end

– Set the elastic band’s visual attributes
myLineBack:setColor(214,184,130);
myLineBack.width = 8;

myLine:setColor(243,207,134);
myLine.width = 10;

– Insert the components of the catapult into a group.
slingshot_container:insert(slingshot_strut_back);
slingshot_container:insert(myLineBack);
slingshot_container:insert(t);
slingshot_container:insert(myLine);
slingshot_container:insert(slingshot_strut_front);

– Boundary for the projectile when grabbed
local bounds = e.target.stageBounds;
bounds.xMax = 200;
bounds.yMax = _H - 250;

if(e.y > bounds.yMax) then
t.y = e.y;
else

end

if(e.x < bounds.xMax) then
t.x = e.x;
else
– Do nothing
end

– If the projectile touch event ends (player lets go)…
elseif(e.phase == “ended” or e.phase == “cancelled”) then

– Remove projectile touch so player can’t grab it back and re-use after firing.
projectiles_container:removeEventListener(“touch”, projectileTouchListener);
– Reset the stage focus
display.getCurrentStage():setFocus(nil);
t.isFocus = false;

– Play the release sound
audio.play(shot);

– Remove the elastic band
if(myLine) then
myLine.parent:remove(myLine); – erase previous line
myLineBack.parent:remove(myLineBack); – erase previous line
myLine = nil;
myLineBack = nil;
end

– Launch projectile
t.bodyType = “dynamic”;
t:applyForce((160 - e.x)*force_multiplier, (_H - 160 - e.y)*force_multiplier, t.x, t.y);
t:applyTorque( 100 )
t.isFixedRotation = false;

– Wait a second before the catapult is reloaded (Avoids conflicts).
t.timer = timer.performWithDelay(1000, function(e)
state:dispatchEvent({name=“change”, state=“fire”});

if(e.count == 1) then
timer.cancel(t.timer);
t.timer = nil;
end

end, 1)

end

end

end

end

–[[

SPAWN projectile FUNCTION

]]–
local function spawnProjectile()

– If there is a projectile available then…
if(projectile.ready)then

projectiles_container = projectile.newProjectile();
– Flag projectiles for removal
projectiles_container.ready = true;
projectiles_container.remove = true;

– Reset the indexing for the visual attributes of the catapult.
slingshot_container:insert(slingshot_strut_back);
slingshot_container:insert(projectiles_container);
slingshot_container:insert(slingshot_strut_front);

– Add an event listener to the projectile.
projectiles_container:addEventListener(“touch”, projectileTouchListener);

end

end
–[[

GAME STATE CHANGE FUNCTION

]]–
function state:change(e)

if(e.state == “fire”) then

– You fired…
– new projectile please
spawnProjectile();

end

end

– Tell the projectile it’s good to go!
projectile.ready = true;
– Spawn the first projectile.
spawnProjectile();
– Create listnener for state changes in the game
state:addEventListener(“change”, state);

function scene:enterScene( event )
print(“Play loaded…”)
storyboard.removeAll()
end

function scene:exitScene( event )
end

function scene:destroyScene( event )
end

---

– END OF YOUR IMPLEMENTATION

–
– “createScene” event is dispatched if scene’s view does not exist
scene:addEventListener( “createScene”, scene )

– “enterScene” event is dispatched whenever scene transition has finished
scene:addEventListener( “enterScene”, scene )

– “exitScene” event is dispatched before next scene’s transition begins
scene:addEventListener( “exitScene”, scene )

– “destroyScene” event is dispatched before view is unloaded, which can be
– automatically unloaded in low memory situations, or explicitly via a call to
– storyboard.purgeScene() or storyboard.removeScene().
scene:addEventListener( “destroyScene”, scene )

return scene[/lua] [import]uid: 141821 topic_id: 29622 reply_id: 118901[/import]