From 90f2879e9afb948fd106ce7813ea482cea63fb5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Sat, 10 Jul 2021 00:03:57 +0300
Subject: [PATCH] lua-test-202107100001

---
 lua-test/main.lua | 140 +++++++++++++++++++++-------------------------
 1 file changed, 65 insertions(+), 75 deletions(-)

diff --git a/lua-test/main.lua b/lua-test/main.lua
index 544be06..d040b28 100644
--- a/lua-test/main.lua
+++ b/lua-test/main.lua
@@ -1,26 +1,19 @@
-local fov = 90 * math.pi / 180
-
 local playerx = 10
 local playery = 10
-local angle = 0
+local angle = 1
 
 local playerspeed = 0
 local playerswspeed = 0
 local playermaxspeed = 100
 
-function love.load()
-	love.mouse.setRelativeMode(true)
-end
-
-function love.mousemoved(x, y, dx, dy)
-	angle = angle - dx / love.graphics.getWidth() * 2 * math.pi
-end
+local sin = {0, 0.707, 1, 0.707, 0, -0.707, -1, -0.707}
+local cos = {1, 0.707, 0, -0.707, -1, -0.707, 0, 0.707}
 
 function love.update(dt)
-	playerx = playerx + math.sin(angle) * playerspeed * dt
-	playerx = playerx + math.cos(angle) * playerswspeed * dt
-	playery = playery + math.cos(angle) * playerspeed * dt
-	playery = playery - math.sin(angle) * playerswspeed * dt
+	playerx = playerx + sin[angle] * playerspeed * dt
+	playerx = playerx + cos[angle] * playerswspeed * dt
+	playery = playery + cos[angle] * playerspeed * dt
+	playery = playery - sin[angle] * playerswspeed * dt
 end
 
 function love.keypressed(key)
@@ -32,11 +25,13 @@ function love.keypressed(key)
 		playerswspeed = playerswspeed + playermaxspeed
 	elseif key == 'd' then
 		playerswspeed = playerswspeed - playermaxspeed
-	elseif key == 'o' then
-		fov = fov + 10 * math.pi / 180
-	elseif key == 'p' then
-		fov = fov - 10 * math.pi / 180
 	elseif key == 'q' then
+		angle = angle + 1
+		if angle > 8 then angle = 1 end
+	elseif key == 'e' then
+		angle = angle - 1
+		if angle < 1 then angle = 8 end
+	elseif key == 'escape' then
 		love.event.quit()
 	end
 end
@@ -59,13 +54,13 @@ function transform(wx, wy)
 	local ty = wy - playery
 
 	-- Player-relative space (rotation)
-	local rx = math.cos(angle) * tx - math.sin(angle) * ty
-	local ry = math.cos(angle) * ty + math.sin(angle) * tx
+	local rx = cos[angle] * tx - sin[angle] * ty
+	local ry = cos[angle] * ty + sin[angle] * tx
 
 	-- -1.0 to +1.0 abstract screen space (perspective)
 	-- Player-relative x maps to *-x*
 	-- Player-relative y maps to *z*
-	local px = -rx / ry / math.tan(fov / 2)
+	local px = -rx / ry
 
 	-- Screen space (scaling and translation)
 	local hwidth = love.graphics.getWidth() / 2
@@ -82,88 +77,83 @@ function drawWall(wx1, wy1, wx2, wy2)
 	local x2, z2 = transform(wx2, wy2)
 
 	if z1 < 0 and z2 < 0 then
-		love.graphics.setColor(0.8, 0.7, 0.7)
-		love.graphics.line(wx1 + hwidth, wy1 + hheight, wx2 + hwidth, wy2 + hheight)
 		-- Fully outside of viewport, don't bother
 		return
 	end
 
-	love.graphics.setColor(1, 0, 0)
-	love.graphics.line(wx1 + hwidth, wy1 + hheight, wx2 + hwidth, wy2 + hheight)
-
 	if z1 < 0 or z2 < 0 then
-		local clippingx = playerx + 0.001*math.sin(angle)
-		local clippingy = playery + 0.001*math.cos(angle)
+		local clippingx = playerx + 0.001*sin[angle]
+		local clippingy = playery + 0.001*cos[angle]
 
 		local x = nil
 		local y = nil
 
-		if wx2 ~= wx1 then
-			local clippingslope = -math.sin(angle)/math.cos(angle)
-			local wallslope = (wy2 - wy1)/(wx2 - wx1)
-			x = (-clippingslope*clippingx + clippingy + wallslope*wx1 - wy1)/(wallslope - clippingslope)
-			y = wallslope*(x - wx1) + wy1
-		else
-			local perclippingslope = -math.cos(angle)/math.sin(angle)
-			local perwallslope = (wx2 - wx1)/(wy2 - wy1)
-			y = (-perclippingslope*clippingy + clippingx + perwallslope*wy1 - wx1)/(perwallslope - perclippingslope)
-			x = perwallslope*(y - wy1) + wx1
+		if angle == 1 or angle == 5 then
+			y = clippingy
+			if wx1 == wx2 then x = wx1
+			elseif (wx1 < wx2) == (wy1 < wy2) then x = wx1 - wy1 + y
+			else x = wx1 + wy1 - y
+			end
+		elseif angle == 3 or angle == 7 then
+			x = clippingx
+			if wy1 == wy2 then y = wy1
+			elseif (wx1 < wx2) == (wy1 < wy2) then y = wy1 - wx1 + x
+			else y = wy1 + wx1 - x
+			end
+		elseif angle == 2 or angle == 6 then
+			if wy1 == wy2 then
+				x = clippingx + clippingy - wy1
+				y = wy1
+			elseif wx1 == wx2 then
+				x = wx1
+				y = clippingx + clippingy - wx1
+			else
+				x = (wx1 + clippingx + clippingy - wy1) / 2
+				y = (wy1 + clippingy + clippingx - wx1) / 2
+			end
+		elseif angle == 4 or angle == 8 then
+			if wy1 == wy2 then
+				x = clippingx - clippingy + wy1
+				y = wy1
+			elseif wx1 == wx2 then
+				x = wx1
+				y = clippingy - clippingx + wx1
+			else
+				x = (wx1 + clippingx - clippingy + wy1) / 2
+				y = (wy1 + clippingy - clippingx + wx1) / 2
+			end
 		end
 
-		if z1 < 0 then
-			x1, z1 = transform(x, y)
-			love.graphics.setColor(0.8, 0.5, 0.5)
-			love.graphics.line(wx1 + hwidth, wy1 + hheight, x + hwidth, y + hheight)
-		else
-			x2, z2 = transform(x, y)
-			love.graphics.setColor(0.8, 0.5, 0.5)
-			love.graphics.line(x + hwidth, y + hheight, wx2 + hwidth, wy2 + hheight)
+		if z1 < 0 then x1, z1 = transform(x, y)
+		else x2, z2 = transform(x, y)
 		end
 	end
 
-	local wall1 = hwidth * 60 / z1 / math.tan(fov / 2)
-	local wall2 = hwidth * 60 / z2 / math.tan(fov / 2)
+	local wall1 = hwidth * 60 / z1
+	local wall2 = hwidth * 60 / z2
 
 	love.graphics.setColor(1, 1, 1)
 	love.graphics.line(x1, hheight - wall1, x2, hheight - wall2)
 	love.graphics.line(x1, hheight + wall1, x2, hheight + wall2)
 	love.graphics.line(x1, hheight - wall1, x1, hheight + wall1)
 	love.graphics.line(x2, hheight - wall2, x2, hheight + wall2)
-
-	if z1 < 0 then
-		love.graphics.setColor(0, 0, 1)
-		square = {
-			wx1 - 5 + hwidth, wy1 - 5 + hheight,
-			wx1 + 5 + hwidth, wy1 - 5 + hheight,
-			wx1 + 5 + hwidth, wy1 + 5 + hheight,
-			wx1 - 5 + hwidth, wy1 + 5 + hheight,
-		}
-		love.graphics.polygon('fill', square)
-		love.graphics.line(hwidth+playerx, hheight+playery, hwidth+wx1, hheight+wy1)
-	end
-	if z2 < 0 then
-		love.graphics.setColor(0, 0, 1)
-		square = {
-			wx2 - 5 + hwidth, wy2 - 5 + hheight,
-			wx2 + 5 + hwidth, wy2 - 5 + hheight,
-			wx2 + 5 + hwidth, wy2 + 5 + hheight,
-			wx2 - 5 + hwidth, wy2 + 5 + hheight,
-		}
-		love.graphics.polygon('fill', square)
-		love.graphics.line(hwidth+playerx, hheight+playery, hwidth+wx2, hheight+wy2)
-	end
 end
 
 function love.draw()
 	local hwidth = love.graphics.getWidth() / 2
 	local hheight = love.graphics.getHeight() / 2
 
-	drawWall(-300, -200, -200, 100)
+	drawWall(-300, -200, -100, 0)
+	drawWall(-100, 0, -300, 200)
 	drawWall(-150, 200, 300, 200)
 	drawWall(300, 200, 300, -200)
 	drawWall(300, -200, -300, -200)
 
-	love.graphics.setColor(0, 1, 0)
-	love.graphics.line(hwidth+playerx, hheight+playery, hwidth+playerx + math.sin(angle + fov/2) * 5, hheight+playery + math.cos(angle + fov/2) * 5)
-	love.graphics.line(hwidth+playerx, hheight+playery, hwidth+playerx + math.sin(angle - fov/2) * 5, hheight+playery + math.cos(angle - fov/2) * 5)
+	love.graphics.setColor(1, 1, 1)
+	anglecw = angle - 1
+	if anglecw < 1 then anglecw = 8 end
+	anglecc = angle + 1
+	if anglecc > 8 then anglecc = 1 end
+	love.graphics.line(hwidth, hheight, hwidth + sin[anglecw] * 5, hheight + cos[anglecw] * 5)
+	love.graphics.line(hwidth, hheight, hwidth + sin[anglecc] * 5, hheight + cos[anglecc] * 5)
 end