Different Collision Reactions to Different Parts of an Image

Caleb_P · November 12, 2015, 4:25pm

Try the ‘isSensor’ property: it stops objects from bouncing off of each other but keeps them checking collisions.

https://docs.coronalabs.com/api/type/Body/isSensor.html

Caleb

InfiSnyp · November 12, 2015, 4:27pm

Are you using physics?

mtuo · November 12, 2015, 5:23pm

Yes, and have done addBody and all that stuff. Im just trying to get them to react differently to different parts of the characters.

InfiSnyp · November 12, 2015, 5:49pm

Can you draw out a sample of what you want on paint? Or something along that time? Like I did a couple posts back.

Thanks!

mtuo · November 12, 2015, 6:43pm

alright so basically if they green cube hits the blue, they score a point, if they hit the red, they lose

InfiSnyp · November 12, 2015, 6:51pm

Does the blue part move up and down?

–SonicX278

Caleb_P · November 12, 2015, 8:55pm

All you’ll need to do is add a body to the red object and a body to the blue object. Set the isSensor parameter on both objects (or maybe just the blue object; all you need is for at least one to have isSensor), then listen for collisions.

To assure that the blue object registers collisions before the red object, you can make the blue object’s physics body just a tiny bit bigger in the X-axis than the red object’s physics body.

A complete working code example:

display.setStatusBar(display.HiddenStatusBar) math.randomseed(os.time()) require("physics") physics.start() physics.setGravity(0, 0) physics.setDrawMode("hybrid") local redWidth = display.contentCenterX \* 0.5 local redHeight = display.contentHeight local blueWidth = display.contentCenterX \* 0.05 local blueHeight = display.contentHeight \* 0.2 local blueMargin = 10 local playerRadius = 20 local red = display.newRect(display.screenOriginX + redWidth \* 0.5, display.contentCenterY, redWidth, redHeight) red:setFillColor(1, 0, 0) red.id = "red" local blue = display.newRect(redWidth - blueWidth \* 0.5, math.random(blueHeight \* 0.5, display.contentHeight - blueHeight \* 0.5), blueWidth, blueHeight) blue:setFillColor(0.5, 0.5, 1) blue.id = "blue" physics.addBody(red, "static", { isSensor = true }) physics.addBody(blue, "static", { isSensor = true, box = { halfWidth = blue.width \* 0.5 + blueMargin \* 0.5, halfHeight = blue.height \* 0.5 } }) local player = display.newCircle(display.contentWidth, display.contentCenterY, playerRadius) player.isBullet = true physics.addBody(player, { radius = player.width \* 0.5 }) function player:collision(event) if event.phase == "began" and not player.collidedAlready then if event.other.id == "red" then print("YOU DIED!") elseif event.other.id == "blue" then print("YOU LIVED!") end player.collidedAlready = true player:setLinearVelocity(0, 0) end end player:setLinearVelocity(-1000, 0) player:addEventListener("collision")

Caleb

InfiSnyp · November 12, 2015, 9:00pm

Thanks Caleb! I’m currently at work so kinda was trying to help with my mobile phone so I can’t check the sample but I’m sure it spot on!

Thanks and good luck!

mtuo · November 12, 2015, 9:15pm

Caleb\_P:

All you’ll need to do is add a body to the red object and a body to the blue object. Set the isSensor parameter on both objects (or maybe just the blue object; all you need is for at least one to have isSensor), then listen for collisions.

To assure that the blue object registers collisions before the red object, you can make the blue object’s physics body just a tiny bit bigger in the X-axis than the red object’s physics body.

A complete working code example:

display.setStatusBar(display.HiddenStatusBar) math.randomseed(os.time()) require("physics") physics.start() physics.setGravity(0, 0) physics.setDrawMode("hybrid") local redWidth = display.contentCenterX \* 0.5 local redHeight = display.contentHeight local blueWidth = display.contentCenterX \* 0.05 local blueHeight = display.contentHeight \* 0.2 local blueMargin = 10 local playerRadius = 20 local red = display.newRect(display.screenOriginX + redWidth \* 0.5, display.contentCenterY, redWidth, redHeight) red:setFillColor(1, 0, 0) red.id = "red" local blue = display.newRect(redWidth - blueWidth \* 0.5, math.random(blueHeight \* 0.5, display.contentHeight - blueHeight \* 0.5), blueWidth, blueHeight) blue:setFillColor(0.5, 0.5, 1) blue.id = "blue" physics.addBody(red, "static", { isSensor = true }) physics.addBody(blue, "static", { isSensor = true, box = { halfWidth = blue.width \* 0.5 + blueMargin \* 0.5, halfHeight = blue.height \* 0.5 } }) local player = display.newCircle(display.contentWidth, display.contentCenterY, playerRadius) player.isBullet = true physics.addBody(player, { radius = player.width \* 0.5 }) function player:collision(event) if event.phase == "began" and not player.collidedAlready then if event.other.id == "red" then print("YOU DIED!") elseif event.other.id == "blue" then print("YOU LIVED!") end player.collidedAlready = true player:setLinearVelocity(0, 0) end end player:setLinearVelocity(-1000, 0) player:addEventListener("collision")

Caleb

Wow this is great, thank you. I have been stuck on this for weeks and this will finally let me finish what I am working on. I truly appreciate it!

mtuo · November 12, 2015, 9:15pm

Thank you for you help!

Caleb_P · November 12, 2015, 9:21pm

Excellent. Glad to help

Caleb