From 142a92b2fca47475132b4deed2d81f8418549e5f Mon Sep 17 00:00:00 2001
From: "Daniele Verducci (Slimpenguin)" <daniele.verducci@gmail.com>
Date: Mon, 2 Jan 2023 10:36:31 +0100
Subject: [PATCH] Working horizontal ray casting and interception

---
 raycaster.py | 100 +++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 89 insertions(+), 11 deletions(-)

diff --git a/raycaster.py b/raycaster.py
index 2e9f264..c78e5a2 100755
--- a/raycaster.py
+++ b/raycaster.py
@@ -8,22 +8,41 @@
 import sys
 import sdl2.ext
 import math
+from time import time
 
 WIN_WIDTH = 640
-WIN_HEIGHT = 480
+WIN_HEIGHT = 640
 DUNGEON_WIDTH = WIN_WIDTH
 DUNGEON_HEIGHT = WIN_HEIGHT
 PLAYER_SPEED = 10
 RAY_LENGTH = 100
+MAP_SCALE = 80
+DOF = 8	# Depth Of Field
+
+MAP = [
+	1, 1, 1, 1, 1, 1, 1, 1,
+	1, 0, 0, 0, 1, 0, 0, 1,
+	1, 0, 0, 0, 1, 1, 0, 1,
+	1, 0, 0, 0, 0, 0, 0, 1,
+	1, 0, 0, 0, 0, 0, 0, 1,
+	1, 0, 1, 0, 0, 0, 0, 1,
+	1, 0, 0, 0, 0, 0, 0, 1,
+	1, 1, 1, 1, 1, 1, 1, 1,
+]
+MAP_SIZE = 8
 
 class Main:
 
 	def __init__(self):
+		# Check valid map
+		if len(MAP) != MAP_SIZE * MAP_SIZE:
+			raise ValueError("Map size is {}, but should be a power of {}", len(MAP), MAP_SIZE)
+
 		# Graphics
 		sdl2.ext.init()
-		self.window = sdl2.ext.Window("Raycaster", size=(WIN_WIDTH, WIN_HEIGHT))
-		self.window.show()
-		self.surface = self.window.get_surface()
+		self.mapWindow = sdl2.ext.Window("2D Map", size=(WIN_WIDTH, WIN_HEIGHT))
+		self.mapWindow.show()
+		self.mapSurface = self.mapWindow.get_surface()
 
 		# Player
 		self.player_position = {"x": int(DUNGEON_WIDTH/2), "y": int(DUNGEON_HEIGHT/2), "r": 0}	# r is rotation in radiants
@@ -70,24 +89,83 @@ class Main:
 						self.player_position["r"] = 0
 					if self.player_position["r"] < 0:
 						self.player_position["r"] = 2*math.pi
-					print(self.player_position)
 
-			sdl2.ext.draw.fill(self.surface, sdl2.ext.Color(0,0,0,0)) # Clears screen
+			sdl2.ext.draw.fill(self.mapSurface, sdl2.ext.Color(0,0,0,0)) # Clears screen
 			self.draw()
-			self.window.refresh()
+			self.mapWindow.refresh()
 		return 0
 
 	def draw(self):
+		self.draw2Dmap()
+		self.drawPlayer()
+		self.drawRays()
+
+	def drawPlayer(self):
 		# Player in 2D map
-		sdl2.ext.draw.fill(self.surface, sdl2.ext.Color(0,255,0,255), (self.player_position["x"] - 2, self.player_position["y"] - 2, 4, 4))
+		sdl2.ext.draw.fill(self.mapSurface, sdl2.ext.Color(0,255,0,255), (self.player_position["x"] - 2, self.player_position["y"] - 2, 4, 4))
 		# Player line of sight in 2D map
 		ray = {
 			"x": int(self.player_position["x"] + math.cos(self.player_position["r"]) * 50), # deltaX + playerX
 			"y": int(self.player_position["y"] + math.sin(self.player_position["r"]) * 50)  # deltaY + playerY
 		}
-		print(self.player_position)
-		sdl2.ext.draw.line(self.surface, sdl2.ext.Color(255,0,0,255), (self.player_position["x"], self.player_position["y"], ray["x"], ray["y"]))
-		return
+		sdl2.ext.draw.line(self.mapSurface, sdl2.ext.Color(255,0,0,255), (self.player_position["x"], self.player_position["y"], ray["x"], ray["y"]))
+
+	def draw2Dmap(self):
+		# 2D map
+		for i in range(len(MAP)):
+			posX = i % MAP_SIZE * MAP_SCALE
+			posY = math.floor(i / MAP_SIZE) * MAP_SCALE
+			color = 0
+			if MAP[i] == 1:
+				color = 255
+			sdl2.ext.draw.fill(self.mapSurface, sdl2.ext.Color(color,color,color,255), (posX, posY, MAP_SCALE - 1, MAP_SCALE - 1))
+
+	def drawRays(self):
+		# Casts rays for raycasting
+		rayAngle = self.player_position["r"]
+		for r in range(1):
+			# Check horizontal lines
+			dof = 0 # Depth of field
+			if rayAngle == 0 or rayAngle == math.pi:
+				print("horiz")
+				# Looking left or right (ray will never intersect parallel lines)
+				rayY = self.player_position["y"]
+				rayX = self.player_position["x"]
+				dof = DOF	# Set depth of field to maximum to avoid unneeded checks
+			elif rayAngle > math.pi:
+				aTan = -1/math.tan(rayAngle)
+				print("down")
+				# Looking up
+				rayY = (int(self.player_position["y"] / MAP_SCALE) * MAP_SCALE) - 0.00001
+				rayX = (self.player_position["y"] - rayY) * aTan + self.player_position["x"]
+				yOffset = -MAP_SCALE
+				xOffset = -yOffset * aTan
+			else:
+				aTan = -1/math.tan(rayAngle)
+				print("up")
+				# Looking down
+				rayY = (int(self.player_position["y"] / MAP_SCALE) * MAP_SCALE) + MAP_SCALE
+				rayX = (self.player_position["y"] - rayY) * aTan + self.player_position["x"]
+				yOffset = MAP_SCALE
+				xOffset = -yOffset * aTan
+
+			# Check if we reached a wall
+			while dof < 8:
+				mapX = int(rayX / MAP_SCALE)
+				mapY = int(rayY / MAP_SCALE)
+				mapArrayPosition = mapY * MAP_SIZE + mapX
+				if mapArrayPosition < MAP_SIZE*MAP_SIZE and MAP[mapArrayPosition] != 0:
+					dof = 8	# Hit the wall: we are done, no need to do other checks
+				else:
+					# Didn't hit the wall: check successive horizontal line
+					rayX = rayX + xOffset
+					rayY = rayY + yOffset
+					dof = dof + 1
+
+			# Draw ray
+			sdl2.ext.draw.line(self.mapSurface, sdl2.ext.Color(0,255,0,255), (self.player_position["x"], self.player_position["y"], rayX, rayY))
+
+