I made my own collision detection code

I made a collision detection code:

init = function()
  posdistx = sqrt(mouse.x-0)
  posdisty = sqrt(mouse.y-0)
  negdistx = sqrt(0-mouse.x)
  negdisty = sqrt(0-mouse.y)
end

update = function()
  posdistx = sqrt(mouse.x-0)
  posdisty = sqrt(mouse.y-0)
  negdistx = sqrt(0-mouse.x)
  negdisty = sqrt(0-mouse.y)
end

draw = function()
  screen.clear("rgb(0,0,0)")
  screen.fillRect(0,0,50,20,"rgb(0,255,0")
  if negdistx <= 5 then
    if posdistx <= 5 then
      if negdisty <= 3 then
        if posdisty <= 3 then
          screen.drawText("hit"0,0,20,"rgb(255,255,255")
        end
      end
    end
  end
end

Will I ever use this, maybe.

What i tend to do with collision is just detect if its in between the x and y values of the collision box and then run a bit of code based on that (like if its in this box set x to 67) by making four of the colliders around the square that will set x y or z to a certain value that will cause a box of collision that will reset population.

What i tend to do with collision is just detect if its in between the x and y values of the collision box and then run a bit of code based on that (like if its in this box set x to 67) by making four of the colliders around the square that will set x y or z to a certain value that will cause a box of collision that will reset population.

I noticed a problem with it.

this is the distance equation:

dist sqrt{(x_2 - x_1)^2 + (y_2-y_1)^2}. what I did is 

This is what I did with it

sqrt{(x_2 - x_1)}

But I was supposed to do this

sqrt{(x_2 - x_1)*(x_2 - x_1)}

here it is fixed

init = function()
  posdistx = sqrt((mouse.x-0)*(mouse.x-0))
  posdisty = sqrt((mouse.y-0)*(mouse.y-0))
  negdistx = sqrt((0-mouse.x)*(0-mouse.x))
  negdisty = sqrt((0-mouse.y)*(0-mouse.y))
end

update = function()
  posdistx = sqrt((mouse.x-0)*(mouse.x-0))
  posdisty = sqrt((mouse.y-0)*(mouse.y-0))
  negdistx = sqrt((0-mouse.x)*(0-mouse.x))
  negdisty = sqrt((0-mouse.y)*(0-mouse.y))
end

draw = function()
  screen.clear("rgb(0,0,0)")
  screen.fillRect(0,0,50,20,"rgb(0,255,0")
  if negdistx <= 25 then
    if posdistx <= 25 then
      if negdisty <= 15 then
        if posdisty <= 15 then
          screen.drawText("hit"0,0,20,"rgb(255,255,255")
        end
      end
    end
  end
end

AABB is the best algorithm for detecting collisions with rectangles if they are parallel to the coordinate axes.

You don't use square root in this algorithm.

You don't ? I was just basing it off the distance equation. Also I am trying to make it so it is all my own code so I don't have to use any libraries

I also just updated the code so it is a whole lot better so I'm just gonna stick to this

collision = function(x,y,w,h)
  hit = false
  posdistx = sqrt((mouse.x-x)*(mouse.x-y))
  posdisty = sqrt((mouse.y-y)*(mouse.y-y))
  negdistx = sqrt((x-mouse.x)*(x-mouse.x))
  negdisty = sqrt((y-mouse.y)*(y-mouse.y))
  if negdistx <= w/2 then
    if posdistx <= w/2 then
      if negdisty <= h/2 then
        if posdisty <= h/2 then
          hit = true
        else
        end
      end
    end
  end
end

collision = function(x,y,w,h, mouse_x, mouse_y)
  hit = false
  posdistx = sqrt((mouse_x-x)*(mouse_x-y))
  posdisty = sqrt((mouse_y-y)*(mouse_y-y))
  negdistx = sqrt((x-mouse_x)*(x-mouse_x))
  negdisty = sqrt((y-mouse_y)*(y-mouse_y))
  if negdistx <= w/2 then
    if posdistx <= w/2 then
      if negdisty <= h/2 then
        if posdisty <= h/2 then
          hit = true
        else
        end
      end
    end
  end
end

init = function()
  screen.fillRect(-80,-10,150,40,"rgb(0,255,0")
  for x = - screen.width / 2 to screen.width / 2 by 2
    for y = - screen.height /2 to screen.height / 2 by 2
      if collision( -80, -10, 150, 40, x, y ) then 
        screen.drawRound( x, y, 1, 1,"rgb(255,0,0)" )
      else 
        screen.drawRound( x, y, 1, 1,"rgb(255,255,255)" )
      end
        
    end
  end
  screen.drawRect(-80,-10,150,40,"rgb(0,255,0")
end

update = function()

end

draw = function()
  if collision( -80, - 10, 150, 40, mouse.x, mouse.y ) then 
    print( "Hit")
  else 
    print( "no hit ")
  end
end

Your code is incorrect. The red area is the one for which your function returns true (it has to be exactly the same as the green rectangle frame). The area returned depends on the location and dimensions of the area you are testing.

AABB is a few lines of code in it

• one is the name of the function
• one starts with return
• one is the end of the function with the word "end"

https://microstudio.dev/i/HomineLudens/aabb/

But all i'm doing is detecting if a mouse is hitting the rectangle, NOT another rectangle.

Here it is detecting two rectangles

init = function()
  player_x = 0
  player_y = -50
  block_x = 0
  block_y = 0
  block_w = 25
  player_w = 20
  block_h = 20
  player_h = 15
  hit = false
end

update = function()
  collision(player_x,player_y,player_w,player_h,block_x,block_y,block_w,block_h)//end       
  if keyboard.UP then
    player_y = player_y + 1
  end
  if keyboard.DOWN then
    player_y = player_y - 1
  end
  if keyboard.LEFT then
    player_x = player_x - 1
  end
  if keyboard.RIGHT then
    player_x = player_x + 1
  end
end

draw = function()
  screen.clear()
  if hit == false then
    screen.fillRect(block_x,block+y,block_w,block_h,"rgb(255,255,0)")
  else
    screen.drawRect(block_x,block+y,block_w,block_h,"rgb(255,255,0)")
  end
  screen.fillRect(player_x,player_y,player_w,player_h,"rgb(255,0,0)")
end




collision = function(x1,y1,w1,h2,x2,y2,w2,h2)
  hit = false
  posdistx = sqrt((x1-x2)*(x1-x2))
  posdisty = sqrt((y1-y2)*(y1-y2))
  negdistx = sqrt((x2-x1)*(x2-x1))
  negdisty = sqrt((y2-y1)*(y2-y1))
  if negdistx <= w2 then
    if posdistx <= w2 then
      if negdisty <= h2 then
        if posdisty <= h2 then
          hit = true
        else
        end
      end
    end
  end
end

set

  block_x = 50
  block_y = 50

and run the code you recently provided. The field returned as true does not match the field seen on the screen.

Check out this code >> https://microstudio.dev/i/microstudio/collisions/ << The official implementation of collision checking - created by MicroStudio developers.

init = function()
  player_x = 0
  player_y = -50
  block_x = 0
  block_y = 0
  block_w = 25
  player_w = 20
  block_h = 20
  player_h = 15
  hit = false
end

update = function()
  collision(player_x,player_y,player_w,player_h,block_x,block_y,block_w,block_h)//end       
  if keyboard.UP then
    player_y = player_y + 1
  end
  if keyboard.DOWN then
    player_y = player_y - 1
  end
  if keyboard.LEFT then
    player_x = player_x - 1
  end
  if keyboard.RIGHT then
    player_x = player_x + 1
  end
end

draw = function()
  screen.clear()
  if hit == false then
    screen.fillRect(block_x,block+y,block_w,block_h,"rgb(255,255,0)")
  else
    screen.drawRect(block_x,block+y,block_w,block_h,"rgb(255,255,0)")
  end
  screen.fillRect(player_x,player_y,player_w,player_h,"rgb(255,0,0)")
end




collision = function(x1,y1,w1,h1,x2,y2,w2,h2)
  hit = false
  posdistx = sqrt((x1-x2)*(x1-x2))
  posdisty = sqrt((y1-y2)*(y1-y2))
  negdistx = sqrt((x2-x1)*(x2-x1))
  negdisty = sqrt((y2-y1)*(y2-y1))
  if negdistx <= w2/2 + w1/2 then
    if posdistx <= w2/2 + w1/2 then
      if negdisty <= h2/2 + h1/2 then
        if posdisty <= h2/2 + h1/2 then
          hit = true
        else
        end
      end
    end
  end
end