Why doesn't the collision work?

magicskillz · December 18, 2016, 11:11pm

@dave1707
I’m using physics but I can’t figure out why the collision doesn’t work

function setup()
p_rect = physics.body(POLYGON,vec2(-10,10),vec2(-10,0),vec2(10,-10),vec2(10,0))
p_rect.x = 0
p_rect.y = 7
p_rect.gravityScale=0   
p_rect.radius = 50
character = physics.body(CIRCLE,50)
    character.x = WIDTH/2
    character.y = 300
    -- Start in the center of the screen
    position = vec2( WIDTH/2, HEIGHT/2 )
    
    -- Create two parameters to play with
    parameter.number( "yCalibration", 0, 2.0, 0.6 )
    parameter.number( "tiltStrength", 1, 40, 10 )
    tab={     -- top      1=draw  0=no draw
            {0,0,0,0,0,0,0,0,1,0},
            {1,1,1,1,1,1,1,1,1,1},  -- bottom
        }
end

function draw()
    background(0, 145, 255, 255)
    --fill(0, 145, 255, 255)
     rect(p_rect.x,p_rect.y,WIDTH,100)
    for x=1,#tab do
        for y=1,#tab[1] do
            if tab[x][y]==1 then
                sprite("Platformer Art:Block Grass",y*70,(#tab+1-x)*70)
            end
        end
    end
    

    moveVec = vec2(Gravity.x, Gravity.y) + vec2( 0, yCalibration )

    position = position + moveVec * tiltStrength
fill(255, 0, 0, 255)
    ellipse(  position.x, character.y, character.radius*2)
    
   
    
end
function collide(contact)
    print("collide")
end

dave1707 · December 18, 2016, 11:37pm

Not sure what you’re doing, but cam.x=cam.x-10 but xx=xx-1 .

magicskillz · December 19, 2016, 12:00am

I’m working on a 2d side scroller game
xx is for the sprite
Cam.x is for the camera

dave1707 · December 19, 2016, 12:08am

OK, but you’re moving xx at a speed of -1 and cam at a speed of -10. So cam is moving 10 times faster then xx.

magicskillz · December 19, 2016, 12:17am

@dave1707
Even once I change x to move at -10
The sprite still disappears off the screen

dave1707 · December 19, 2016, 12:56am

@magicskillz Do a forum search for camera scrolling. There are a lot of examples doing what you’re trying.

magicskillz · December 19, 2016, 10:53pm

New Question:
Can someone explain go you can use a table to store all the ‘tiles’ for the game
Ps:I already saw @Ignatz’s 2d platform game on his blog!

dave1707 · December 19, 2016, 11:21pm

supportedOrientations(LANDSCAPE_ANY)
displayMode(FULLSCREEN)

function setup()
    tab={}
    for z=1,14 do
        table.insert(tab,vec2(z*70,100))    -- 70 is the width of the sprite
    end
end

function draw()
    background(40, 40, 50)
    for a,b in pairs(tab) do
        sprite("Platformer Art:Block Grass",b.x,b.y)
    end
end

magicskillz · December 19, 2016, 11:37pm

@dave1707
What about using a table like this?

N=No block
1=Block

    local world={ 
    'nnn1n1111',
    '1111111111',
    'n1n1n1n11',
    '1nn111n11'

dave1707 · December 20, 2016, 12:05am

displayMode(FULLSCREEN)
supportedOrientations(PORTRAIT_ANY)

function setup()
    tab={   {0,0,1,1,0,0,1,1,1,0},  -- top      1=draw  0=no draw
            {0,1,1,1,1,0,0,1,1,1},
            {1,0,0,1,1,0,0,0,1,1},
            {0,1,1,1,1,1,0,0,0,0},
            {0,0,0,1,1,1,0,0,0,1},
            {1,1,1,0,0,0,1,0,1,0},
            {0,0,0,0,0,1,1,1,1,1},
            {1,0,0,1,1,0,0,0,1,1},
            {0,1,1,1,1,1,0,0,0,0},
            {0,0,0,1,1,1,0,0,0,1},
            {0,0,0,0,0,1,1,1,1,1},
            {1,0,0,1,1,0,0,0,1,1},
            {0,1,1,1,1,1,0,0,0,0},  -- bottom
        }
end

function draw()
    background(40, 40, 50)
    for x=1,#tab do
        for y=1,#tab[1] do
            if tab[x][y]==1 then
                sprite("Platformer Art:Block Grass",y*70,(#tab+1-x)*70)
            end
        end
    end
end

magicskillz · December 20, 2016, 4:34am

I’m using physics but I can’t figure out why the collsiom doesn’t work

Correct Code:

function setup()
p_rect = physics.body(POLYGON,vec2(-10,10),vec2(-10,0),vec2(10,-10),vec2(10,0))
p_rect.x = 0
p_rect.y = 7
p_rect.gravityScale=0   
p_rect.radius = 50
character = physics.body(CIRCLE,50)
    character.x = WIDTH/2
    character.y = 300
    -- Start in the center of the screen
    position = vec2( WIDTH/2, HEIGHT/2 )
    
    -- Create two parameters to play with
    parameter.number( "yCalibration", 0, 2.0, 0.6 )
    parameter.number( "tiltStrength", 1, 40, 10 )
    tab={     -- top      1=draw  0=no draw
            {0,0,0,0,0,0,0,0,1,0},
            {1,1,1,1,1,1,1,1,1,1},  -- bottom
        }
end

function draw()
    background(0, 145, 255, 255)
    --fill(0, 145, 255, 255)
     rect(p_rect.x,p_rect.y,WIDTH,100)
    for x=1,#tab do
        for y=1,#tab[1] do
            if tab[x][y]==1 then
                sprite("Platformer Art:Block Grass",y*70,(#tab+1-x)*70)
            end
        end
    end
    

    moveVec = vec2(Gravity.x, Gravity.y) + vec2( 0, yCalibration )

    position = position + moveVec * tiltStrength
fill(255, 0, 0, 255)
    ellipse(  position.x, character.y, character.radius*2)
    
   
    
end
function collide(contact)
    print("collide")
end

dave1707 · December 20, 2016, 3:26pm

@magicskillz The collision does work. When the 2 circles collide, the word collision prints. Apparently you’re expecting something to happen that you’re not writing code for. Be more specific about what you think isn’t happening.

magicskillz · December 20, 2016, 4:07pm

@dave1707
Feel so dumb I used the wrong project

This is the correct code

function setup()
p_rect = physics.body(POLYGON,vec2(-10,10),vec2(-10,0),vec2(10,-10),vec2(10,0))
p_rect.x = 0
p_rect.y = 7
p_rect.gravityScale=0   
p_rect.radius = 50
character = physics.body(CIRCLE,50)
    character.x = WIDTH/2
    character.y = 300
    -- Start in the center of the screen
    position = vec2( WIDTH/2, HEIGHT/2 )
    
    -- Create two parameters to play with
    parameter.number( "yCalibration", 0, 2.0, 0.6 )
    parameter.number( "tiltStrength", 1, 40, 10 )
    tab={     -- top      1=draw  0=no draw
            {0,0,0,0,0,0,0,0,1,0},
            {1,1,1,1,1,1,1,1,1,1},  -- bottom
        }
end

function draw()
    background(0, 145, 255, 255)
    --fill(0, 145, 255, 255)
     rect(p_rect.x,p_rect.y,WIDTH,100)
    for x=1,#tab do
        for y=1,#tab[1] do
            if tab[x][y]==1 then
                sprite("Platformer Art:Block Grass",y*70,(#tab+1-x)*70)
            end
        end
    end
    

    moveVec = vec2(Gravity.x, Gravity.y) + vec2( 0, yCalibration )

    position = position + moveVec * tiltStrength
fill(255, 0, 0, 255)
    ellipse(  position.x, character.y, character.radius*2)
    
   
    
end
function collide(contact)
    print("collide")
end

Also fixed code above

dave1707 · December 20, 2016, 6:04pm

@magicskillz Maybe this link will be of interest to you. I wrote the code more than 2 years ago. https://codea.io/talk/discussion/5302/starter-game-4#latest

magicskillz · December 20, 2016, 6:10pm

@dave1707
Thanks for the link but I still don’t see how I could use that for my program above

dave1707 · December 20, 2016, 6:32pm

@magicskillz I thought it might be similar to what you were starting. Does the code you show above work the way you want or is there something wrong. I’m not sure from your comment if you fixed the code. When I run your code, the ball falls thru the blocks. Not sure if it isn’t supposed to or what your intent is.

magicskillz · December 20, 2016, 6:33pm

@dave1707
I don’t want the ball to fall through the ground that’s why I’m asking this question and I didn’t fix my code
I also can’t mess around with the x and y positions of the ground without the code not working or looking weird

dave1707 · December 20, 2016, 6:51pm

@magicskillz You’re going to have to create a physics object for each Sprite position you draw.

magicskillz · December 20, 2016, 6:56pm

@dave1707
Why can’t I just create a large rectangle at the bottom like what I did before?

The reason you couldn’t see the rect when you play the code is because I gave it the same colour as the background

dave1707 · December 20, 2016, 7:23pm

I guess you can do it that way if you’re not going to change the 0’s and 1’s in the table once it’s set up.