CODEWITHSUNDEEP
eventsluatouchcoronasdktransparency
Guilherme Oliveira
Guilherme Oliveira

Reputation: 11

Corona SDK - touch transparency issue. Event on physics body?

Newbie here! :P

I'm trying to create a game in Corona where animals falls from the top of the screen and keep bouncing. When you touch an animal it disappears.

I've drawn all the animals like circles, then, I added a circular physics body to it. The images are PNG with transparency.

The problem is, some details of the animals, such as ears and paws, they are outside of the physics body (what I want, because it seems a better collision this way). Moreover, when I touch outside the animal image sometimes it is pressed on the alpha region of my image and it is counted as a tap, but I have not actually tapped in the animal.

I would like to it disappear when i click only on its physical body region.

Anyone knows how to handle this? Is there a way to add a touch handler for the physics body? (The collision works pretty fine, it's just the touch that is related to the image instead of the physics body).

local rect = display.newImage("img/Animals/cow_a1.png");
rect.x = 60 + math.random( 160 )
rect.y = -100
physics.addBody( rect, { density=9, friction=0.3, bounce=0.3,radius=27} )
function rect:touch(e)
            -- Remove the animals from screen and memory
            removeAnimal(self);
end
-- Add event listener to the cow
rect:addEventListener("touch", rect);

Upvotes: 1

Views: 392

Answers (1)

Mohammad Ali Saatchi
Mohammad Ali Saatchi

Reputation: 124

This is because of the rectangular image space. try using MASK on your animal objet with HIT TEST option on (true): try this link for masking images

here is an example:

local displayGroupTmp = display.newGroup( )
    displayGroupTmp.id = id + 1
    -- creating a slice
    local circleSize = Constants.screenX*3.8/4 - 20
    local background = display.newImageRect( displayGroupTmp, "images/slice.png", circleSize/2, circleSize*1.5/2 )
    background.anchorX = 0
    background.anchorY = 0.66
    background.x = Constants.screenX/2 + deltaX
    background.y = Constants.screenY/2 + deltaY
    background:setFillColor( color[1], color[2], color[3] )
    -- setting mask of an object to identify the true bounding of the background
    local mask = graphics.newMask( "images/sliceMask.png" )
    -- mask.anchorX = 0
    background.maskX = background.x
    background.maskY = background.y
    background:setMask( mask )
    background.maskScaleX, background.maskScaleY = 0.38,0.38
    background.isHitTestMasked = true

Upvotes: 2

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