Fixed collision conditions

[lightcycles-love.git] / scene.lua

diff --git a/scene.lua b/scene.lua
index 3460899aa5dfe11add47fa59fad7b8bfc2f944c4..08b96de3dcdd39f9e7f4f2c04a3c927891e2133c 100644 (file)
--- a/scene.lua
+++ b/scene.lua
@@ -5,6 +5,7 @@ require 'player'
 
 
 scene = {}
+scene.paused = false
 scene.width = love.graphics.getWidth()
 scene.height = love.graphics.getHeight()
 scene.players = {}
@@ -16,7 +17,7 @@ scene.grid.delta = 50
 -- load
 function scene:load()
     table.insert(scene.players, require('players/1'))
-    table.insert(scene.players, require('players/2'))
+    --table.insert(scene.players, require('players/2'))
 end
 
 -- draw
@@ -41,6 +42,14 @@ end
 function scene:draw()
     self:drawGrid()
     self:drawPlayers()
+
+    -- draw intersection if it's there
+    if self.intersection then
+        love.graphics.setColor(0, 255, 0)
+        love.graphics.line(self.intersection.a)
+        love.graphics.setColor(0, 0, 255)
+        love.graphics.line(self.intersection.b)
+    end
 end
 
 -- update
@@ -50,13 +59,91 @@ function scene:updatePlayers(dt)
     end
 end
 
+function doLinesIntersect(x1,y1, x2,y2, x3,y3, x4,y4)
+    if x1 == x2 and x3 == x4
+    or y1 == y2 and y3 == y4
+    then
+        -- if lines are parallel, no intersection!
+        return false
+    else
+        -- if lines are not parallel, they must intersect
+        -- do segments overlap?
+        if
+            (
+                (x1 <= x3 and x3 <= x2 or x1 <= x4 and x4 <= x2)
+                or
+                (x3 <= x1 and x1 <= x4 or x3 <= x2 and x2 <= x4)
+            ) and (
+                (y1 <= y3 and y3 <= y2 or y1 <= y4 and y4 <= y2)
+                or
+                (y3 <= y1 and y1 <= y4 or y3 <= y2 and y2 <= y4)
+            )
+        then
+            scene.paused = true
+            scene.intersection = {
+                a = {x1,y1, x2,y2},
+                b = {x3,y3, x4,y4},
+                }
+            return true
+        end
+    end
+end
+
+function doesLineIntersectPlayerPaths(path, x1,y1, x2,y2)
+    local cache = {}
+    cache.a = {}
+    cache.b = {}
+    -- for every line in path,
+    -- check intersection with player line
+    for k,v in pairs(path) do
+        if #cache.a == 2 then
+            if #cache.b == 2 then
+                if doLinesIntersect(x1,y1, x2,y2, cache.a[1],cache.a[2], cache.b[1],cache.b[2]) then
+                    return true
+                end
+            end
+            cache.b = cache.a
+            cache.a = {}
+        end
+        table.insert(cache.a,v)
+    end
+    return false
+end
+
+-- love collision handler
+function collision(player)
+    print('Player '..tostring(player)..' crashed!')
+    --love.event.quit()
+end
+love.handlers.collision = collision
+
+function scene:handleCollisions()
+    -- calculate the last line for each player from current position
+    -- check if line intersects any other path line
+    -- if so, raise collision event for player
+    for _,player in pairs(self.players) do
+        local x1 = player.path[#player.path-1]
+        local y1 = player.path[#player.path]
+        local x2 = player.position.x
+        local y2 = player.position.y
+
+        -- check intersection against each existing path
+        for _,player2 in pairs(self.players) do
+            if doesLineIntersectPlayerPaths(player2.path, x1, y1, x2, y2) then
+                love.event.push('collision', player)
+            end
+        end
+    end
+end
+
 function scene:update(dt)
     self:updatePlayers(dt)
+    self:handleCollisions()
 end
 
 -- quit
 function scene:quit()
-    for i,player in pairs(self.players) do
-        print('Player '..i..' generated '.. #player.path / 2 .. ' path points')
+    for _,player in pairs(self.players) do
+        print(tostring(player)..' generated '.. #player.path / 2 .. ' path points')
     end
 end