Add cathedral scene generator, render script, and design docs

Makefile

@@ -272,10 +272,13 @@ gen_scene:
 			@$(CC) -Wall -Wextra -Werror -o gen_scene tools/gen_scene.c -lm
 			@echo "Built gen_scene tool"
 
+render-cathedral:	$(NAME) gen_scene
+			@scripts/render_cathedral.sh $(ARGS)
+
 testclean:
 			$(RM) run_test_math run_test_camera run_test_intersections run_test_lighting run_test_parsing run_test_pbr run_benchmark
 			$(RM) cov_test_math cov_test_intersections cov_test_lighting cov_test_parsing cov_test_all
 			$(RM) -r coverage
 			$(RM) *.gcno *.gcda src/*.gcno src/*.gcda tests/*.gcno tests/*.gcda
 
-.PHONY:		re all clean fclean sanitize debug release test testclean coverage regression regression-generate lint benchmark gen_scene
+.PHONY:		re all clean fclean sanitize debug release test testclean coverage regression regression-generate lint benchmark gen_scene render-cathedral

README.md

@@ -1,6 +1,6 @@
 # miniRT
 
-![Cathedral Ruins](./saves/cathedral_ruins.bmp?raw=true)
+![Cathedral Ruins](./renders_preview/cathedral_ruins.png?raw=true)
 
 **A basic RayTracer using minilibX**    
 project of 42 Paris's common-core

scenes/cathedral_ruins.rt

@@ -2,7 +2,10 @@ R	2560	1440
 A	0.08	200,190,170
 E
 
-c	0.0,6.0,12.0	0.03,0,0	70
+c	0.0,12.0,25.0	0.055,0,0	70
+c	-4.0,7.0,18.0	0.04,-0.03,0	70
+c	8.0,6.0,-15.0	0.03,0.3,0	70
+c	0.0,2.0,16.0	0.0,0,0	70
 
 l	-3.0,25.0,-5.0	0.9	255,240,200
 l	5.0,20.0,5.0	0.6	255,235,190

scripts/bmp2png.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+"""Convert BMP files to PNG format."""
+import sys
+from PIL import Image
+
+def convert(src, dst=None):
+    if dst is None:
+        dst = src.rsplit('.', 1)[0] + '.png'
+    img = Image.open(src)
+    img.save(dst, 'PNG')
+    print(f"{src} -> {dst} ({img.width}x{img.height})")
+
+if __name__ == '__main__':
+    if len(sys.argv) < 2:
+        print("Usage: bmp2png.py <input.bmp> [output.png]")
+        sys.exit(1)
+    convert(sys.argv[1], sys.argv[2] if len(sys.argv) > 2 else None)

scripts/render_cathedral.sh

@@ -0,0 +1,129 @@
+#!/bin/bash
+# Render the cathedral ruins scene
+# Generates the .rt file via gen_scene and renders it with miniRT
+#
+# Usage: scripts/render_cathedral.sh [OPTIONS]
+#   --preview         Quick render at 640x360
+#   --full            Full resolution render (2560x1440)
+#   --generate-only   Create .rt file without rendering
+#   --png             Convert output BMP to PNG (requires Pillow)
+#   --width N         Custom width (default: 1280)
+#   --height N        Custom height (default: 720)
+#   --threads N       Thread count (default: auto)
+#   --seed N          RNG seed for debris placement (default: 42)
+#   --output PATH     Output BMP path (default: saves/cathedral_ruins.bmp)
+#   --scene PATH      Use existing .rt file instead of generating
+
+set -euo pipefail
+
+PROJECT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
+
+WIDTH=1280
+HEIGHT=720
+THREADS="auto"
+SEED=42
+OUTPUT="$PROJECT_DIR/saves/cathedral_ruins.bmp"
+SCENE_FILE=""
+GENERATE_ONLY=0
+USE_EXISTING=0
+CONVERT_PNG=0
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --preview)
+            WIDTH=640; HEIGHT=360 ;;
+        --full)
+            WIDTH=2560; HEIGHT=1440 ;;
+        --generate-only)
+            GENERATE_ONLY=1 ;;
+        --png)
+            CONVERT_PNG=1 ;;
+        --width)
+            WIDTH="$2"; shift ;;
+        --height)
+            HEIGHT="$2"; shift ;;
+        --threads)
+            THREADS="$2"; shift ;;
+        --seed)
+            SEED="$2"; shift ;;
+        --output)
+            OUTPUT="$2"; shift ;;
+        --scene)
+            SCENE_FILE="$2"; USE_EXISTING=1; shift ;;
+        --help|-h)
+            head -16 "$0" | tail -14
+            exit 0 ;;
+        *)
+            echo "Unknown option: $1" >&2
+            exit 1 ;;
+    esac
+    shift
+done
+
+# Build miniRT if missing
+if [ ! -f "$PROJECT_DIR/miniRT" ]; then
+    echo "Building miniRT..."
+    make -C "$PROJECT_DIR" -j"$(nproc)" 2>&1 | tail -1
+fi
+
+# Build gen_scene if missing
+if [ ! -f "$PROJECT_DIR/gen_scene" ]; then
+    echo "Building gen_scene..."
+    make -C "$PROJECT_DIR" gen_scene 2>&1
+fi
+
+# Generate scene file
+if [ "$USE_EXISTING" -eq 0 ]; then
+    SCENE_FILE="$PROJECT_DIR/scenes/cathedral_ruins_gen.rt"
+    echo "Generating cathedral scene (${WIDTH}x${HEIGHT}, seed=${SEED})..."
+    "$PROJECT_DIR/gen_scene" --preset cathedral \
+        --width "$WIDTH" --height "$HEIGHT" \
+        --seed "$SEED" \
+        --output "$SCENE_FILE"
+    echo "Scene file: $SCENE_FILE"
+    SHAPE_COUNT=$(grep -c "^[a-z]" "$SCENE_FILE" || true)
+    echo "Shape/element count: $SHAPE_COUNT"
+fi
+
+if [ "$GENERATE_ONLY" -eq 1 ]; then
+    echo "Done (generate-only mode)."
+    exit 0
+fi
+
+# Render
+mkdir -p "$(dirname "$OUTPUT")"
+echo ""
+echo "Rendering ${WIDTH}x${HEIGHT} with --threads=${THREADS}..."
+echo "Output: $OUTPUT"
+echo "This may take a while for large resolutions."
+echo ""
+
+START=$(date +%s)
+
+cd "$PROJECT_DIR"
+xvfb-run -a "$PROJECT_DIR/miniRT" "$SCENE_FILE" -save \
+    --output "$OUTPUT" --threads="$THREADS" || {
+    echo "Retrying with default output path..."
+    xvfb-run -a "$PROJECT_DIR/miniRT" "$SCENE_FILE" -save \
+        --threads="$THREADS"
+    mv -f "$PROJECT_DIR/miniRT.bmp" "$OUTPUT"
+}
+
+END=$(date +%s)
+ELAPSED=$((END - START))
+MINUTES=$((ELAPSED / 60))
+SECONDS=$((ELAPSED % 60))
+
+echo ""
+echo "=== Render Complete ==="
+echo "Time: ${MINUTES}m ${SECONDS}s"
+ls -lh "$OUTPUT" | awk '{print "Size:", $5}'
+file "$OUTPUT" | sed 's/.*: /Format: /'
+
+# Convert to PNG if requested
+if [ "$CONVERT_PNG" -eq 1 ]; then
+    PNG_OUTPUT="${OUTPUT%.bmp}.png"
+    echo ""
+    echo "Converting to PNG..."
+    python3 "$PROJECT_DIR/scripts/bmp2png.py" "$OUTPUT" "$PNG_OUTPUT"
+fi