Hello fellow Corona Developers!
I have been having some major issues with implementing the “Angry Bunny” slingshot example by FIXDIT Ltd. (Thank you for sharing your code! :).
Anyways, I have the slingshot part to quite well. However, when I try to make the projectile to trigger and event when it hits a dynamic object flying from the bottom of the screen, it works rather strangely. What I mean is that I have noticed that most of the times the projectile goes THROUGH the objects that’s supposed to hit and create the event (collision). In other cases, the projectile, according to some print I have included within the collision function, hits the flying dynamic objects, but at a rather strange, x,y location: the collision happens at a different X and Y location on the screen.
Here’s the projectile.lua file, from the code example by FIXDIT Ltd.
--
-- Abstract: Part of a tutorial documenting how to put together an 'Angry Birds'/'Hot Cross Bunnies' elastic catapult in CoronaSDK.
-- Visit: http://www.fixdit.com regarding support and more information on this tutorial.
-- Hot Cross Bunnies is now available in the iTunes App Store: http://itunes.apple.com/app/hot-cross-bunnies/id432734772?mt=8
--
-- Version: 1.0
--
-- Copyright (C) 2011 FIXDIT Ltd. All Rights Reserved.
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy of
-- this software and associated documentation files (the "Software"), to deal in the
-- Software without restriction, including without limitation the rights to use, copy,
-- modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
-- and to permit persons to whom the Software is furnished to do so, subject to the
-- following conditions:
--
-- The above copyright notice and this permission notice shall be included in all copies
-- or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-- INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-- PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-- FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-- OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-- DEALINGS IN THE SOFTWARE.
-- main.lua (Part of a tutorial documenting how to put together an 'Angry Birds'/'Hot Cross Bunnies' elastic catapult in CoronaSDK.)
module(..., package.seeall)
\_W = display.contentWidth
\_H = display.contentHeight
-- Pass state reference
state = {};
-- Bullet starts off in-active
ready = false;
-- Pass audio references
shot = {};
band\_stretch = {};
pop = {}
local tin\_sound = audio.loadSound("tin\_sound.mp3")
local playTinSound = function()
audio.play(tinsound)
end
function newProjectile()
-- Import easing plugin
local easingx = require("easing");
-- Bullet properties
local bun\_bullet = {
name = "fruta",
type = "bullet",
density=0.15,
friction=0.2,
bounce=0.5,
size = 26,
rotation = 1
}
-- Init bullet
local bullet = display.newImageRect("" .. bun\_bullet.name .. ".png", 40,40);
-- Place bullet
bullet.x = 149; bullet.y = \_H + 123 ;
bullet.myName = "bullet"
bullet.hit = "bullet"
bullet.type = "bullet"
bullet.isBullet = true
-- 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 = 0.2;
bullet.isBullet = true;
bullet.isSensor = true;
-- add collision here to see..
--OnCollision With floor
local function onBulletCollision(self, event)
bullet.bodyType = "dynamic"
if (event.other.hit == "obstacle") then
audio.play(tin\_sound)
print("Hit BARREL")
end
if ( event.other.hit == "vase" ) then
audio.play(tin\_sound)
print("BULLET!")
self:removeSelf()
return true
end
end
bullet.collision = onBulletCollision
bullet:addEventListener( "collision" , bullet )
-- Transition the bullet into position each time it's spawned
transition.to(bullet, {time=900, y=\_H - 140, transition = easingx.easeOutElastic});
return bullet;
end
And here’s the targetVase.lua file which creates a vase object that I later use to spawn flying vases (IGNORE FUNCTION checkThreshold():
module(..., package.seeall);
\_W = display.contentWidth
\_H = display.contentHeight
--Thresholds fed from game.lua
thresholds = {};
--Pass the state machine reference
state = {};
--Helper function for comparing balloon height (obj1) to threshold (obj2)
local function checkThreshold(obj1,obj2)
if(obj1 and obj2) then
if(obj1.y \< obj2[1].boundary and obj1.y \> obj2[2].boundary) then
--Fire a method once, if you want
if(obj1.multiplier == nil) then
--Do something
end
--In case you want to see the threshold change in the terminal window
--print(obj2[1].multiplier .. ": thresh 1");
obj1.multiplier = obj2[1].multiplier;
elseif(obj1.y \< obj2[2].boundary and obj1.y \> obj2[3].boundary) then
--Fire a method once, if you want
if(obj1.multiplier == obj2[1].multiplier) then
obj1:flash();
end
--In case you want to see the threshold change in the terminal window
--print(obj2[2].multiplier .. ": thresh 2");
obj1.multiplier = obj2[2].multiplier;
elseif(obj1.y \< obj2[3].boundary and obj1.y \> -10) then
--Fire a method once, if you want
if(obj1.multiplier == obj2[2].multiplier) then
obj1:flash();
end
--In case you want to see the threshold change in the terminal window
--print(obj2[3].multiplier .. ": thresh 3");
obj1.multiplier = obj2[3].multiplier;
elseif(obj1.y \< -10) then
if(obj1.timer) then
obj1:pop();
end
end
end
end
function newVase(velocity)
local vase = display.newImageRect("vase.png", 45, 50)
vase.x = math.random(\_W \* 0.5 + 139, \_W\*0.5 + 149)
vase.y = 400
vase.rotation = -90
physics.addBody(vase, { radius = 25});
--physics.addBody(cherries, {density=1.2, bounce = 0, radius = 5})
vase.type = "vase"
vase.hit = false
vase.multiplier = nil
vase.points = 1
vase.myName = "vase"
--[[local balloon = display.newCircle(0, 0, 40);
balloon:setFillColor(m.random(1,255), m.random(1,255), m.random(1,255));
balloon.x = \_W/2; balloon.y = \_H+20;
--Set up some custom properties
balloon.type = "balloon";
balloon.hit = false;
balloon.multiplier = nil;
balloon.points = 1;--]]
--Set up properties to store transition.to's
vase.tween = {start={},finish={}};
function vase:flash()
local xS = self.xScale;
local yS = self.yScale;
local factor = 0.3
local function tweenBack()
transition.to(self, {time=150, xScale = 1, yScale = 1})
end
self.tween.finish = tweenBack;
self.tween.start = transition.to(self, {time=100, xScale = xS + factor, yScale = yS + factor, onComplete = self.tween.finish});
end
-- Collision Detection for the bullet
function vase:collision(e)
if(e.phase == "began") then
if (e.other.type == "bullet") then
print("Hit Vase!!")
audio.play(tin\_sound)
-- self: removeSelf()
local function collide()
--do points and stuff here..
end
local tmr = timer.performWithDelay(1, collide, 1)
elseif(e.other.type == "rightWall") then
print("RIGHT WALL")
end
elseif(e.phase == "ended") then
--if bullet collides with vase
if (e.other.type == "vase") then
local function collide()
--e.other.
end
elseif (e.other.type =="floor") then
local function collide()
self:removeSelf()
self = nil
end
local tmr = timer.performWithDelay(1,collide, 1)
end
end
end --end of bullet function collision
function vase:pop()
--Tell the state machine that a pop has happened
state:dispatchEvent({name="change", state="pop"})
--Cancel the object's timer
if(self.timer) then
timer.cancel(self.timer);
self.timer = nil;
end
--immediately hide the object;
self.isVisible = false
if(self.tween.start) then
self.tween.start = nil;
end
if(self.tween.finish) then
self.tween.finish = nil;
end
self.tween = nil;
--Finally, remove the object
self:removeSelf();
self = nil;
collectgarbage("collect");
end
--Start checking the y threshold continuously using the helper function defined earlier
vase.timer = timer.performWithDelay(20, function(e)
checkThreshold(balloon, thresholds);
end, -1)
physics.addBody(vase, "kinematic", {density=0, bounce=0, friction=0, radius=40});
vase:setLinearVelocity(0,velocity \* -2.5);
return vase;
end And here’s PART of main.lua file where I call all other files for instantiating the vase and slingshot etc…
--------------------------
--THE HEART OF SLINGSHOT-
--------------------------
-- BULLET COLLISION
--SPAWN CHERRIES UPWARDS--
local spawnCherries = function()
physics.setGravity(0, - 0.6);
--cherries = display.newImage("cherries.png", math.random(206), 406);
cherries = display.newImageRect("vase.png", 45, 50)
-- cherries = display.newImageRect("cherries.png", 40,40)
-- cherries.x = math.random( 12, 50)
cherries.x = math.random(\_W \* 0.5 + 139, \_W\*0.5 + 149)
cherries.y = 400
cherries.rotation = -90
physics.addBody(cherries, { radius = 25});
--physics.addBody(cherries, {density=1.2, bounce = 0, radius = 5})
cherries.hit = "cherries"
cherries.myName = "cherries"
local function splashPoints300(object)
gushCircle = display.newImageRect ( "points\_300.png",64, 64 )
gushCircle.x = \_W\*0.5 + 200
gushCircle.y = \_H\*0.5 + 12
function transtion1( event )
trans = transition.to(gushCircle, { tim = 1000, alpha = 0.8, onComplete=finishFunction1})
end
function finishFunction1( event )
trans = transition.to(gushCircle, { time = 10100, alpha = 0, onComplete=transition1})
end
transition.to(gushCircle, { time = 1600, y = gushCircle.y - 110, x = gushCircle.x +20, alpha = 0,onComplete= transition1} )
end
local function splashAnimation800(object)
audio.play(tin\_sound)
print("Vase Hit from splash!")
gushCircle = display.newImageRect ( "grapes\_splash.png",64, 64 )
gushCircle.x = \_W\*0.5 + 200
gushCircle.y = \_H\*0.5 + 59
function transtion1( event )
trans = transition.to(gushCircle, { time = 1000, alpha = 0.8, onComplete=finishFunction1})
end
function finishFunction1( event )
trans = transition.to(gushCircle, { time = 10100, alpha = 0, onComplete=transition1})
end
transition.to(gushCircle, { time = 1600, y = gushCircle.y - 110, x = gushCircle.x + 24, alpha = 0,onComplete= transition1} )
end
--onCollision With barrel
local function onObstacleCollision(self, event)
if ( event.other.hit == "obstacle" ) then
--audio.play(tin\_sound)
--splashAnimationGrapes()
print("HIT OBSTACLE!")
splashAnimation800()
splashPoints300()
--print("Vase Hit!")
self:removeSelf()
return true
elseif ( event.other.hit =="rightWall") then
print("HIT WALL!")
end
end
obstacle.collision = onObstacleCollision
obstacle:addEventListener( "collision" , obstacle )
--OnCollision With floor
local function onCherriesCollision(self, event)
if ( event.other.hit == "bullet" ) then
--audio.play(tin\_sound)
--splashAnimationGrapes()
splashAnimation800()
splashPoints300()
--print("Vase Hit!")
self:removeSelf()
return true
elseif ( event.other.hit =="rightWall") then
self:removeSelf()
print("HIT WALL!")
end
end
cherries.collision = onCherriesCollision
cherries:addEventListener( "collision" , cherries )
end
local function spawnVase(number)
local function spawn(e)
--Create an instance of a balloon
--and assign it a random linear velocity
-- local v = vases.newVase(m.random(100,370));
local v = vases.newVase(m.random(50, 100))
--Store the balloon instance in the balloons table
--using the table number as the index
vaso[v] =v;
vaso[v].x = m.random(\_W \* 0.5 + 139, \_W\*0.5 + 149);
--Flag the balloon for removal later
vaso[v].remove = true;
--insert the balloon into the foreground group
localGroup:insert(vaso[v]);
--cancel and nil timer when done
if(e.count == number) then
timer.cancel(tmr);
tmr = nil;
end
end
tmr = timer.performWithDelay(2000, spawn, number);
end
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
-------------------
---Change Scene-----
-------------------
local moveToScene = function(event)
--Example scene change with parameters
--director:changeScene( { label="Scene Reloaded" }, "screen2","moveFromRight" )
--Example scene change without parameters
--director:changeScene( "screen1", "crossfade" )
end
------------------
-- Code here
------------------
background\_image = display.newImageRect("mode\_3\_bg.png", 480, 320)
slingshot\_strut\_front = display.newImage("sling\_left.png", true)
slingshot\_strut\_back = display.newImage("sling\_right.png", true)
--spring = display.newImageRect("spring\_good.png", 98, 98)
obstacle = display.newImageRect("barrel.png", 64, 64)
obstacle.myName = "obstacle"
obstacle.hit = "obstacle"
leftWall = display.newRect(0,0,0, \_H);
leftWall.myName = "leftWall"
rightWall = display.newRect(\_W, 0, 1, \_H);
rightWall.hit = "rightWall"
--invisible\_floor = display.newImageRect("invisible\_floor.png", 980, 1)
--====================================================================--
-- INITIALIZE, Every Display Object must get shoved into the local Display Group
-- Example: localGroup:insert( background )
--====================================================================--
local initVars = function ()
localGroup:insert(background\_image)
localGroup:insert(leftWall)
localGroup:insert(rightWall)
localGroup:insert(obstacle)
--localGroup:insert(invisible\_floor)
slingshot\_container:insert(slingshot\_strut\_front)
slingshot\_container:insert(slingshot\_strut\_back)
--slingshot\_container:insert(projectiles\_container)
--localGroup:insert(spring)
-- Transfer variables to the projectile classes
projectile.shot = shot
projectile.band\_stretch = band\_stretch
--POSITION OBJECTS
background\_image.x = \_W\*0.5
background\_image.y = \_H\*0.5
--[[invisible\_floor.x = \_W;
invisible\_floor.y = \_H;
physics.addBody ( invisible\_floor, "static", {bounce=0} )
invisible\_floor.hit = "floor"
invisible\_floor.myName = "floor"--]]
--slingshot
slingshot\_strut\_front.x = 138
slingshot\_strut\_front.y = \_H - 123
slingshot\_strut\_front.rotation = -30
slingshot\_strut\_back.x = 189
slingshot\_strut\_back.y = \_H - 147
slingshot\_strut\_back.rotation = -23
obstacle.x = \_W\*0.5 + 120
obstacle.y = \_H - 45
--[[spring.x = \_W\*0.5 + 230
spring.y = \_W\*0.5 - 200
spring.hit = "trampoline"
physics.addBody(spring, "static", { bounce = 1.4, friction = 0.4})
spring.rotation = 230--]]
-- Move catapult up
slingshot\_container.y = 98;
slingshot\_container.x = -98
--WRAPPIN WALLS WITH PHYSICS ENGINE --
physics.addBody(leftWall, "static", {bounce = 0.01});
physics.addBody(rightWall, "static", {bounce = 0.01});
physics.addBody(obstacle, "static", {bounce = 0.04})
----LISTENERS---
-- 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);
timerSpawnCherries = timer.performWithDelay( 2000, spawnCherries, 0)
-- spawnVase(21)
end I have been trying to figure this one out for a while now, and I can’t seem to find the solution for this. Essentially, all I want to be able to do is have the player stretch the slingshot( which is working fine), and launch the projectile, which in return will hit flying objects and destroy/break that object (or objects if it hits more than one at once). That’s all I want to be able to do. Your help will be highly appreciated.
Thank you in advance. [import]uid: 75258 topic_id: 20126 reply_id: 320126[/import]
[import]uid: 52491 topic_id: 20126 reply_id: 78649[/import]