Collision (Need Help)

[TheScriptan]

I've been working with simple rectangle collision, and got an error: "attempt to index global 'rectangle' (a nil value) '".
What does it means? Btw here is the code:

Code: Select all

function game_load()
	rectangle = {
		{x = 0, y = 0, w = 128, h = 128},
		{x = 400, y = 300, w = 128, h = 128}
	}
end

function game_update(dt)
	player_update(dt)
	
	if player.x > love.graphics.getWidth() / 2 then
		camera.x = player.x - love.graphics.getWidth() / 2
	end
	if player.y > love.graphics.getWidth() / 2 then
		camera.y = player.y - love.graphics.getWidth() / 2
	end
end

function game_draw()
	camera:set()
	if CheckCollision(player.x, player.y, player.w, player.h, rectangle[2].x, rectangle[2].y, rectangle[2].w, rectangle[2].h) then
		love.graphics.setColor(255,0,0)
	else
	love.graphics.setColor(255,255,255)
	end
	for i=1, #rectangle do
		love.graphics.rectangle("fill",rect[i].x,rectangle[i].y,rectangle[i].w,rectangle[i].h)
	end
	love.graphics.print("FPS: ".. love.timer.getFPS(),camera.x+16,camera.y+16)
	player_draw()
	
	camera:unset()
end

function CheckCollision(x1, y1, w1, h1, x2, y2, w2, h2)
	if x1 > (x2 + w2) or (x1 + w1) < x2 then return false end
	if y1 > (y2 + h2) or (y1 + h1) < y2 then return false end
	return true
end

[Hexenhammer]

for i=1, #rectangle do
love.graphics.rectangle("fill",rect.x,rectangle.y,rectangle.w,rectangle.h)
end

I think you mean "rectangle" here, right?

[TheScriptan]

Umm, yeah, but the error goes to 23 line, which is

Code: Select all

if CheckCollision bla bla bla

[Hexenhammer]

"attempt to index global 'rectangle' (a nil value) '"

That just means you try to use an object called "rectanlge" but no such object exists. "A nil value" = does not exist in Luaspeak. It says "global" because all objects are global by default in Lua i.e. they can be used everywhere. According to that logic non-existing objects are "global" too.. in a way. And yes that error message certainly wasn't written to be newbie friendly.

[Hexenhammer]

Umm, yeah, but the error goes to 23 line, which is

Code: Select all

if CheckCollision bla bla bla

I don't see any other obvious problems. Post the entire source (i.e. something people can actually run) then I could easily tell you.

[TheScriptan]

"attempt to index global 'rectangle' (a nil value) '"

"rectanlge"

But there is no words like rectanlge, i can't find it.

[Hexenhammer]

"attempt to index global 'rectangle' (a nil value) '"

"rectanlge"

But there is no words like rectanlge, i can't find it.

I did not write that. I said you wrote "rect" instead of "rectangle", and that causes an error because there is no object called "rect" but there is an object called "rectangle".. all over your code.

[TheScriptan]

Code looks now like this:

Code: Select all

function game_load()
	rectangle = {
		{x = 0, y = 0, w = 128, h = 128},
		{x = 400, y = 300, w = 128, h = 128}
	}
end

function game_update(dt)
	player_update(dt)
	
	if player.x > love.graphics.getWidth() / 2 then
		camera.x = player.x - love.graphics.getWidth() / 2
	end
	if player.y > love.graphics.getWidth() / 2 then
		camera.y = player.y - love.graphics.getWidth() / 2
	end
end

function game_draw()
	camera:set()
	if CheckCollision(player.x, player.y, player.w, player.h, rectangle[2].x, rectangle[2].y, rectangle[2].w, rectangle[2].h) then
		love.graphics.setColor(255,0,0)
	else
	love.graphics.setColor(255,255,255)
	end
	for i=1, #rectangle do
		love.graphics.rectangle("fill",rectangle[i].x,rectangle[i].y,rectangle[i].w,rectangle[i].h)
	end
	love.graphics.print("FPS: ".. love.timer.getFPS(),camera.x+16,camera.y+16)
	player_draw()
	
	camera:unset()
end

function CheckCollision(x1, y1, w1, h1, x2, y2, w2, h2)
	if x1 > (x2 + w2) or (x1 + w1) < x2 then return false end
	if y1 > (y2 + h2) or (y1 + h1) < y2 then return false end
	return true
end

Same error

[Hexenhammer]

Again, post the entire source. I don't get any errors in the parts of the source I can run. I guess you are destroying the "rectangle" object somewhere.. somewhere in the parts of the code you did not post.

[TheScriptan]

Here is .love file, maybe you can find out what is wrong with if, because still can't find it, i used rectangle object only in game.lua