From adf11abd163d423d53cd1b10dc93b82cb452aef2 Mon Sep 17 00:00:00 2001
From: "Daniele Verducci (Slimpenguin)" <daniele.verducci@gmail.com>
Date: Fri, 6 Jan 2023 10:44:40 +0100
Subject: [PATCH] Rendering textures (for now, a single texture row))

---
 v2/raycaster.py | 41 +++++++++++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/v2/raycaster.py b/v2/raycaster.py
index 52f918a..8bf3079 100755
--- a/v2/raycaster.py
+++ b/v2/raycaster.py
@@ -12,8 +12,8 @@ import time
 
 MAP_WIN_WIDTH = 640
 MAP_WIN_HEIGHT = 640
-RAYCAST_WIN_WIDTH = 800
-RAYCAST_WIN_HEIGHT = 480
+RAYCAST_WIN_WIDTH = 400
+RAYCAST_WIN_HEIGHT = 255
 DUNGEON_WIDTH = MAP_WIN_WIDTH
 DUNGEON_HEIGHT = MAP_WIN_HEIGHT
 PLAYER_SPEED = 10
@@ -43,6 +43,14 @@ MAP = [
 MAP_SIZE = 16
 DOF = 2*MAP_SIZE	# Depth Of Field
 
+TEXTURE = [
+	1, 0, 1, 0,
+	0, 1, 0, 1,
+	1, 0, 1, 0,
+	0, 1, 0, 1,
+]
+TEXTURE_SIZE = 4
+
 class Main:
 
 	def __init__(self):
@@ -274,18 +282,31 @@ class Main:
 
 			# Calculate line height based on distance
 			lineHeight = MAP_SCALE * RAYCAST_WIN_HEIGHT / shortestDist
-			if lineHeight > RAYCAST_WIN_HEIGHT:
-				lineHeight = RAYCAST_WIN_HEIGHT
 			# Center line vertically in window
 			lineOffset = RAYCAST_WIN_HEIGHT / 2 - lineHeight / 2
 
-			# Simulate lighting based on wall incidence
-			color = sdl2.ext.Color(255,255,255,255)
-			if vertDist > horizDist:
-				color = sdl2.ext.Color(200,200,200,255)
+			# Draw pixels vertically from top to bottom to obtain a line
+			for textureColumnPixel in range(0, TEXTURE_SIZE):
+				# Calc texture segment length on screen
+				textureSegmentLength = lineHeight / TEXTURE_SIZE
+				textureSegmentStart = lineOffset + textureColumnPixel * textureSegmentLength
+				textureSegmentEnd = textureSegmentStart + textureSegmentLength
+				# Obtain texture value in the pixel representing the current segment
+				texColumn = 1
+				texel = TEXTURE[texColumn + textureColumnPixel * TEXTURE_SIZE]
+				# Calculate shading
+				shading = 255
+				if vertDist > horizDist:
+					shading = 127
+				# Calculate color resulting from texture pixel value + shading
+				color = sdl2.ext.Color(texel*shading,texel*shading,texel*shading,255)
+				# Clipping
+				lineEnd = textureSegmentEnd
+				if textureSegmentEnd > lineOffset + lineHeight:
+					textureSegmentEnd = lineOffset + lineHeight
+				# Draw segment
+				sdl2.ext.draw.line(self.raycastSurface, color, (i, int(textureSegmentStart), i, int(textureSegmentEnd)))
 
-			# Draw line
-			sdl2.ext.draw.line(self.raycastSurface, color, (i, int(lineOffset), i, int(lineOffset + lineHeight)))
 
 	def dist(self, ax, ay, bx, by):
 		return math.sqrt((bx-ax)*(bx-ax) + (by-ay)*(by-ay))