close out the restructure's open items

- boot_info: label the ESP32 reset reasons Zephyr's hwinfo driver maps to 0
  (USB-Serial-JTAG/JTAG reset -> DEBUG, power glitch -> BROWNOUT, CPU lockup,
  eFuse -> HARDWARE); get pwrmgt.bootreason no longer says Unknown after a flash
- mqtt: the uplink credentials struct moves to adapters/mqtt/uplink_creds.h,
  so the adapter no longer includes an app header (layout unchanged: the
  struct is persisted raw)
- gps: one off-levels routine for standby/off and System OFF; the sleep line
  stays asserted in standby and drops at System OFF, as upstream's
  sleep_gps/stop_gps/powerOff; System OFF now asserts reset before cutting
  GPS_EN
- doom: sprites solid with a one-pixel black halo, boss drawn 1.5x on the
  floor; the L2 boss was invisible from the spawn on 1-bit panels

docs/ARCHITECTURE.md

@@ -85,6 +85,7 @@ zephcore/
 │   ├── gps/ZephyrGPSManager.cpp/h      # GNSS state machine, fix validation, public API
 │   ├── gps/gps_power.cpp, gps_module_cfg.cpp, gps_internal.h  # module power; module configuration + diag
 │   ├── mqtt/ZephyrMQTTPublisher.c/h    # MQTT packet publisher (observer / uplink)
+│   ├── mqtt/uplink_creds.h             # WiFi/MQTT/location credentials struct (persisted by app/observer_creds)
 │   ├── ota/wifi_ota.c/h           # WiFi SoftAP + HTTP firmware upload
 │   ├── rng/ZephyrRNG.cpp/h        # Hardware CSPRNG with PRNG fallback
 │   ├── sensors/                   # ZephyrSensorManager (upstream SensorManager) over the I2C env sensors + power monitors
@@ -1271,7 +1272,10 @@ cleared register. nRF implements `hwinfo_clear_reset_cause()`;
 ESP32 does not, so the weak stub returns `-ENOSYS` and nothing is cleared
 there. That is harmless on ESP32, whose cause comes from `esp_reset_reason()`
 and does not accumulate across boots, but the capture is what readers should
-rely on rather than the register.
+rely on rather than the register. Zephyr's ESP32 hwinfo driver returns 0 for
+the reasons it has no case for; `boot_info` maps those itself (USB-Serial-JTAG
+and JTAG resets, i.e. every esptool flash, to `DEBUG`; power glitch to
+`BROWNOUT`; CPU lockup; eFuse error to `HARDWARE`).
 
 Everything below is software: bounded stall detection in the layer that owns the
 state machine. Each entry names what it recovers, because several are

docs/DESIGN.md

@@ -185,7 +185,7 @@ flowchart TB
 | V2 | `helpers/CommonCLI.cpp` includes the GPS manager, `ZephyrBoard`, WiFi OTA and UI headers (it serves `gps sync`, `start dfu`, `start ota`, display and input rotation). Sensors and GPS settings go through upstream's `SensorManager` since 2026-09-25. | Accepted: the remaining includes serve ZephCore-only commands. |
 | V3 | `helpers/boot_prefs.h` includes the GPS manager (applies GPS prefs at boot, as upstream's `applyGpsPrefs()`). | Accepted. |
 | V4 | The joystick UI calls `CompanionMesh` directly. | **Accepted by decision**: it runs on the main thread, so the calls are safe, and upstream's UITask reads `the_mesh` the same way. One access point (`JoystickUITask::getMesh()`). |
-| V5 | The MQTT adapter includes `app/observer_creds.h`. | Open, small. |
+| V5 | The MQTT adapter included `app/observer_creds.h`. | **Resolved 2026-09-26**: the credentials struct lives in `adapters/mqtt/uplink_creds.h`; the roles keep its persistence. |
 
 ### 5.4 Component inventory
 
@@ -358,6 +358,6 @@ upstream alignment (§9).
 
 1. `CompanionMesh.cpp` (~3.5k lines) and `CommonCLI.cpp` (~2k) remain the largest files, though now in upstream's
    shape (one handler per opcode; upstream command layout).
-2. V5 (§5.3).
-3. Merging the GPS standby and shutdown pin sequences needs current measurements first.
-4. ESP32 reset cause is not reported (`get pwrmgt.bootreason` shows `Unknown`).
+
+None beyond that: the items left open at the end of the restructure (V5, the GPS off sequences, the ESP32 reset
+cause) were closed on 2026-09-26.

zephcore/adapters/gps/gps_power.cpp

@@ -151,6 +151,58 @@ static const struct gpio_dt_spec gps_resetb_gpio = GPIO_DT_SPEC_GET(DT_ALIAS(gps
 static bool gps_gpio_configured = false;
 #endif
 
+/* The off levels, shared by gps_power_control(false) and System OFF: reset
+ * and resetb asserted (the module held in reset while its supply is gated,
+ * so it starts cleanly on the next power-on), the enable and rtcint
+ * de-asserted, VRTC de-asserted unless keep_vrtc (warm standby).
+ *
+ * The sleep line is the one difference: runtime standby/off leaves it
+ * asserted, System OFF drops it -- as upstream, whose T1000-E sleep_gps() and
+ * stop_gps() drive GPS_SLEEP_INT HIGH and only powerOff() drives it LOW.
+ *
+ * gpio_pin_configure_dt() on every line: a boot with the GPS off never ran
+ * the power-on path, so the pins may not be outputs yet. */
+static void gps_drive_off_levels(bool keep_vrtc, bool system_off)
+{
+#if HAS_GPS_RESET
+	if (gpio_is_ready_dt(&gps_reset_gpio)) {
+		gpio_pin_configure_dt(&gps_reset_gpio, GPIO_OUTPUT_ACTIVE);
+	}
+#endif
+#if HAS_GPS_VRTC
+	if (!keep_vrtc && gpio_is_ready_dt(&gps_vrtc_gpio)) {
+		gpio_pin_configure_dt(&gps_vrtc_gpio, GPIO_OUTPUT_INACTIVE);
+	}
+#else
+	ARG_UNUSED(keep_vrtc);
+#endif
+#if HAS_GPS_POWER_CONTROL
+	/* INACTIVE, not LOW: physical LOW leaves an active-low enable asserted. */
+	if (gpio_is_ready_dt(&gps_enable_gpio)) {
+		gpio_pin_configure_dt(&gps_enable_gpio, GPIO_OUTPUT_INACTIVE);
+		gps_gpio_configured = true;
+	}
+#endif
+#if HAS_GPS_SLEEP
+	if (system_off && gpio_is_ready_dt(&gps_sleep_gpio)) {
+		gpio_pin_configure_dt(&gps_sleep_gpio, GPIO_OUTPUT_INACTIVE);
+	}
+#else
+	ARG_UNUSED(system_off);
+#endif
+#if HAS_GPS_RTCINT
+	if (gpio_is_ready_dt(&gps_rtcint_gpio)) {
+		gpio_pin_configure_dt(&gps_rtcint_gpio, GPIO_OUTPUT_INACTIVE);
+	}
+#endif
+#if HAS_GPS_RESETB
+	/* Declared GPIO_ACTIVE_LOW, so ACTIVE drives it LOW. */
+	if (gpio_is_ready_dt(&gps_resetb_gpio)) {
+		gpio_pin_configure_dt(&gps_resetb_gpio, GPIO_OUTPUT_ACTIVE);
+	}
+#endif
+}
+
 /* GPS power control with warm standby support.
  * @param on        true = power on, false = power off
  * @param keep_vrtc When powering off: true = keep VRTC alive (warm standby,
@@ -263,62 +315,7 @@ void gps_power_control(bool on, bool keep_vrtc)
 		}
 #endif
 	} else {
-		/* Power off sequence */
-#if HAS_GPS_RESET
-		/* Hold GPS in reset during power-off — matches Arduino sleep_gps()/stop_gps().
-		 * Ensures chip sees RESET asserted when GPS_EN is asserted on next
-		 * power-on, preventing uncontrolled startup before the reset pulse.
-		 * Configure-on-first-use (mirrors the GPS_EN pin below): on a
-		 * boot-with-GPS-off the power-on path never ran, so the pin isn't an
-		 * output yet — gpio_pin_set_dt() alone would leave it floating instead
-		 * of asserting reset. GPIO_OUTPUT_ACTIVE drives the active (asserted)
-		 * level directly. */
-		if (gpio_is_ready_dt(&gps_reset_gpio)) {
-			if (!gps_gpio_configured) {
-				gpio_pin_configure_dt(&gps_reset_gpio, GPIO_OUTPUT_ACTIVE);
-			} else {
-				gpio_pin_set_dt(&gps_reset_gpio, 1);
-			}
-		}
-#endif
-
-#if HAS_GPS_VRTC
-		if (!keep_vrtc) {
-			/* Full power-off: VRTC off too (cold start on next wake) */
-			if (gpio_is_ready_dt(&gps_vrtc_gpio)) {
-				if (!gps_gpio_configured) {
-					gpio_pin_configure_dt(&gps_vrtc_gpio, GPIO_OUTPUT_INACTIVE);
-				} else {
-					gpio_pin_set_dt(&gps_vrtc_gpio, 0);
-				}
-			}
-		}
-		/* else: warm standby — VRTC stays asserted, preserving
-		 * ephemeris/almanac/RTC for fast re-acquisition (~1-2 µA) */
-#endif
-		if (gpio_is_ready_dt(&gps_enable_gpio)) {
-			if (!gps_gpio_configured) {
-				gpio_pin_configure_dt(&gps_enable_gpio, GPIO_OUTPUT_INACTIVE);
-				gps_gpio_configured = true;
-			} else {
-				gpio_pin_set_dt(&gps_enable_gpio, 0);
-			}
-		}
-
-#if HAS_GPS_RESETB
-		/* Assert RESETB when GPS is off (Arduino sleep_gps/stop_gps).
-		 * The alias is declared GPIO_ACTIVE_LOW, so this drives it LOW. */
-		if (gpio_is_ready_dt(&gps_resetb_gpio)) {
-			gpio_pin_configure_dt(&gps_resetb_gpio, GPIO_OUTPUT_ACTIVE);
-		}
-#endif
-
-#if HAS_GPS_RTCINT
-		/* GPS_RTC_INT stays de-asserted during sleep/off (same as normal operation) */
-		if (gpio_is_ready_dt(&gps_rtcint_gpio)) {
-			gpio_pin_configure_dt(&gps_rtcint_gpio, GPIO_OUTPUT_INACTIVE);
-		}
-#endif
+		gps_drive_off_levels(keep_vrtc, false);
 
 #if HAS_GPS_VRTC
 		LOG_INF("GPS power OFF (%s)", keep_vrtc ?
@@ -332,12 +329,9 @@ void gps_power_control(bool on, bool keep_vrtc)
 #endif
 }
 
-/* Put every GPS control line this board declares into its System OFF state:
- * the power enable, and where present VRTC, sleep and rtcint, de-asserted;
- * reset and resetb asserted, holding the module in reset while its supply is
- * gated -- the same levels gps_power_control(false) leaves them at.
- * Uses gpio_pin_configure_dt() so pins are properly set even if
- * gps_power_control() was never called (GPIO not yet configured). */
+/* Put every GPS control line this board declares into its System OFF state
+ * (see gps_drive_off_levels()), the regulator rail off and VRTC off too.
+ * Configures the pins, so it works even if gps_power_control() never ran. */
 void gps_power_off_for_shutdown(void)
 {
 #if HAS_GPS_POWER_REGULATOR
@@ -346,40 +340,7 @@ void gps_power_off_for_shutdown(void)
 		gps_reg_enabled = false;
 	}
 #endif
-#if HAS_GPS_POWER_CONTROL
-	/* INACTIVE: physical LOW leaves an active-low enable asserted, i.e. the
-	 * module still powered across System OFF. */
-	if (gpio_is_ready_dt(&gps_enable_gpio)) {
-		gpio_pin_configure_dt(&gps_enable_gpio, GPIO_OUTPUT_INACTIVE);
-	}
-#endif
-#if HAS_GPS_VRTC
-	if (gpio_is_ready_dt(&gps_vrtc_gpio)) {
-		gpio_pin_configure_dt(&gps_vrtc_gpio, GPIO_OUTPUT_INACTIVE);
-	}
-#endif
-#if HAS_GPS_RESET
-	/* ACTIVE, matching the power-off path: reset stays asserted across
-	 * System OFF, as Arduino stop_gps() leaves it. */
-	if (gpio_is_ready_dt(&gps_reset_gpio)) {
-		gpio_pin_configure_dt(&gps_reset_gpio, GPIO_OUTPUT_ACTIVE);
-	}
-#endif
-#if HAS_GPS_SLEEP
-	if (gpio_is_ready_dt(&gps_sleep_gpio)) {
-		gpio_pin_configure_dt(&gps_sleep_gpio, GPIO_OUTPUT_INACTIVE);
-	}
-#endif
-#if HAS_GPS_RTCINT
-	if (gpio_is_ready_dt(&gps_rtcint_gpio)) {
-		gpio_pin_configure_dt(&gps_rtcint_gpio, GPIO_OUTPUT_INACTIVE);
-	}
-#endif
-#if HAS_GPS_RESETB
-	if (gpio_is_ready_dt(&gps_resetb_gpio)) {
-		gpio_pin_configure_dt(&gps_resetb_gpio, GPIO_OUTPUT_ACTIVE);
-	}
-#endif
+	gps_drive_off_levels(false, true);
 }
 
 #if HAS_GNSS

zephcore/adapters/mqtt/ZephyrMQTTPublisher.c

@@ -13,7 +13,7 @@
 
 #include "ZephyrMQTTPublisher.h"
 #include "ZephyrWiFiStation.h"   /* g_wifi_events, WIFI_READY_BIT, zc_wifi_station_* */
-#include "observer_creds.h"
+#include "uplink_creds.h"
 
 #include <zephyr/kernel.h>
 #include <zephyr/net/mqtt.h>

zephcore/adapters/mqtt/uplink_creds.h

@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: MIT
+ * Uplink credentials: WiFi, MQTT broker and location for the observer and the
+ * repeater uplink. Read by the WiFi station and the MQTT publisher; loaded,
+ * saved and edited by the roles (app/observer_creds.h).
+ *
+ * The struct is persisted as raw bytes (/lfs/repeater/obs_creds): keep the
+ * field order and sizes.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct ObserverCreds {
+	char wifi_ssid[64];      /* WiFi network name */
+	char wifi_psk[64];       /* WiFi password (empty = open network) */
+	char mqtt_host[128];     /* MQTT broker hostname, e.g. "abydos.hu" */
+	uint16_t mqtt_port;      /* MQTT broker port, e.g. 8883 */
+	uint8_t  mqtt_tls;       /* 1 = TLS (no cert verify), 0 = plaintext */
+	char mqtt_user[64];      /* MQTT username */
+	char mqtt_password[64];  /* MQTT password */
+	char mqtt_iata[8];       /* IATA location code, e.g. "BUD", "BTS", "VIE" */
+	uint8_t  _reserved[1];   /* alignment / future use */
+	int32_t  lat_e6;          /* latitude  × 1 000 000 (e.g. 47497900 = 47.497900°N) */
+	int32_t  lon_e6;          /* longitude × 1 000 000 (e.g. 19040200 = 19.040200°E) */
+};
+
+/* Apply sensible defaults to a freshly-zeroed creds struct. */
+static inline void observer_creds_init(struct ObserverCreds *creds)
+{
+	creds->mqtt_port = 8883;
+	creds->mqtt_tls  = 1;
+}
+
+#ifdef __cplusplus
+}
+#endif

zephcore/app/observer_creds.h

@@ -11,24 +11,12 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#include "../adapters/mqtt/uplink_creds.h"  /* struct ObserverCreds, observer_creds_init() */
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-struct ObserverCreds {
-	char wifi_ssid[64];      /* WiFi network name */
-	char wifi_psk[64];       /* WiFi password (empty = open network) */
-	char mqtt_host[128];     /* MQTT broker hostname, e.g. "abydos.hu" */
-	uint16_t mqtt_port;      /* MQTT broker port, e.g. 8883 */
-	uint8_t  mqtt_tls;       /* 1 = TLS (no cert verify), 0 = plaintext */
-	char mqtt_user[64];      /* MQTT username */
-	char mqtt_password[64];  /* MQTT password */
-	char mqtt_iata[8];       /* IATA location code, e.g. "BUD", "BTS", "VIE" */
-	uint8_t  _reserved[1];   /* alignment / future use */
-	int32_t  lat_e6;          /* latitude  × 1 000 000 (e.g. 47497900 = 47.497900°N) */
-	int32_t  lon_e6;          /* longitude × 1 000 000 (e.g. 19040200 = 19.040200°E) */
-};
-
 /* Load creds from /lfs/repeater/obs_creds.
  * Returns true on success; on failure fills struct with safe zero defaults. */
 bool observer_creds_load(struct ObserverCreds *creds, const char *base_path);
@@ -36,13 +24,6 @@ bool observer_creds_load(struct ObserverCreds *creds, const char *base_path);
 /* Save creds to /lfs/repeater/obs_creds. Returns true on success. */
 bool observer_creds_save(const struct ObserverCreds *creds, const char *base_path);
 
-/* Apply sensible defaults to a freshly-zeroed creds struct. */
-static inline void observer_creds_init(struct ObserverCreds *creds)
-{
-	creds->mqtt_port = 8883;
-	creds->mqtt_tls  = 1;
-}
-
 #ifdef __cplusplus
 }
 #endif

zephcore/helpers/boot_info.c

@@ -12,11 +12,38 @@
 
 #include <stdio.h>
 
+#if defined(CONFIG_SOC_FAMILY_ESPRESSIF_ESP32)
+#include <esp_system.h>
+#endif
+
 LOG_MODULE_REGISTER(zephcore_boot, CONFIG_ZEPHCORE_MAIN_LOG_LEVEL);
 
 static uint32_t s_reset_cause;
 static bool s_reset_cause_valid;
 
+#if defined(CONFIG_SOC_FAMILY_ESPRESSIF_ESP32)
+/* Zephyr's ESP32 hwinfo driver reports 0 for the reasons it has no case for,
+ * the commonest being ESP_RST_USB: esptool's reset over USB-Serial-JTAG, i.e.
+ * every flash. Map those onto the nearest RESET_* bit so they are labelled
+ * instead of "Unknown". */
+static uint32_t esp_unmapped_reset_cause(void)
+{
+	switch (esp_reset_reason()) {
+	case ESP_RST_USB:
+	case ESP_RST_JTAG:
+		return RESET_DEBUG;
+	case ESP_RST_PWR_GLITCH:
+		return RESET_BROWNOUT;
+	case ESP_RST_CPU_LOCKUP:
+		return RESET_CPU_LOCKUP;
+	case ESP_RST_EFUSE:
+		return RESET_HARDWARE;
+	default:
+		return 0;
+	}
+}
+#endif
+
 /* POST_KERNEL: before main() on every role. */
 static int boot_info_init(void)
 {
@@ -27,6 +54,12 @@ static int boot_info_init(void)
 		return 0;
 	}
 
+#if defined(CONFIG_SOC_FAMILY_ESPRESSIF_ESP32)
+	if (cause == 0) {
+		cause = esp_unmapped_reset_cause();
+	}
+#endif
+
 	s_reset_cause = cause;
 	s_reset_cause_valid = true;
 

zephcore/helpers/ui/doom_game.c

@@ -606,8 +606,8 @@ static const uint16_t spr_portal_b[16] = {
 
 /*
  * Fireball — a solid ball confined to the middle 8 rows of the 16×16 cell, so
- * it renders at roughly half an enemy's apparent size without the shared
- * sprite blitter needing a scale argument. Solid, unlike the outlined portal
+ * it renders at eye level, at roughly half an enemy's apparent size, through
+ * the shared blitter at scale 100. Solid, unlike the outlined portal
  * diamond, so the two never read as the same thing.
  */
 static const uint16_t spr_fireball[16] = {
@@ -663,14 +663,41 @@ static const uint16_t *get_sprite_16(const struct doom_enemy *e)
 
 /* ========== RAYCASTER ========== */
 
+/* The sprite texel under screen pixel (sc, sr) of a sprite drawn at
+ * [x0, x0 + w) x [y0, y0 + h). */
+static inline bool sprite_texel_on(const uint16_t *sprite, int sc, int sr,
+				   int x0, int y0, int w, int h)
+{
+	int tex_x = (sc - x0) * 16 / w;
+	int tex_y = (sr - y0) * 16 / h;
+
+	if (tex_x > 15) tex_x = 15;
+	if (tex_y > 15) tex_y = 15;
+	return (sprite[tex_y] & (0x8000 >> tex_x)) != 0;
+}
+
+static inline void clear_px(int x, int y)
+{
+	render_fb[(y / 8) * SCREEN_W + x] &= (uint8_t)~(1U << (y & 7));
+}
+
 /*
- * Render one 16×16 sprite at world position (wx, wy).
- * Shared by both the portal and all enemy sprites.
+ * Render one 16×16 sprite at world position (wx, wy), scale_pct percent of a
+ * wall's height with its feet on the floor. Shared by the portal, the enemies
+ * and the fireballs.
+ *
+ * Sprites are solid with a one-pixel black halo, not distance-dithered like
+ * the walls. On a 1-bit panel a dithered sprite ORed over the dithered floor
+ * band at the horizon has nothing to contrast against: the L2 boss, which
+ * starts 8-12 tiles away, was a few dots at best and a grey smudge in the
+ * floor's own pattern at 4 tiles. The halo pass clears first, then the fill
+ * sets; both honour the zbuffer, so a nearer wall is never cut into.
  */
 static void render_one_sprite(const uint16_t *sprite,
 			      fixed_t wx, fixed_t wy,
 			      fixed_t inv_det,
-			      struct doom_player *p)
+			      struct doom_player *p,
+			      int scale_pct)
 {
 	fixed_t sx = wx - p->x;
 	fixed_t sy = wy - p->y;
@@ -686,46 +713,49 @@ static void render_one_sprite(const uint16_t *sprite,
 		fp_to_int(fp_div(fp_mul(transform_x,
 			fp_from_int(SCREEN_W)), transform_y));
 
-	int sprite_h = fp_to_int(fp_abs(fp_div(
+	int base_h = fp_to_int(fp_abs(fp_div(
 		fp_from_int(SCREEN_H), transform_y)));
-	if (sprite_h < 3) return;
-	if (sprite_h > SCREEN_H * 2) sprite_h = SCREEN_H * 2;
+	if (base_h > SCREEN_H * 2) base_h = SCREEN_H * 2;
 
-	int draw_start_y = (SCREEN_H - sprite_h) / 2;
-	int draw_end_y   = draw_start_y + sprite_h;
+	int sprite_h = base_h * scale_pct / 100;
+	if (sprite_h < 3) return;
+
+	int draw_end_y   = (SCREEN_H + base_h) / 2;  /* the floor line */
+	int draw_start_y = draw_end_y - sprite_h;
 	int draw_start_x = sprite_screen_x - sprite_h / 2;
 	int draw_end_x   = sprite_screen_x + sprite_h / 2;
+	int sprite_w     = draw_end_x - draw_start_x;
 
-	/* Floor for sprites: at 8+ tiles the wall fade (brightness 1) passes one
-	 * dither cell in 16, so the boss, which starts ~11 tiles away in a
-	 * corner, drew as a few dots or nothing while its fireballs hit. Walls
-	 * keep the full fade; sprites keep a silhouette. */
-	int brightness = dist_to_brightness(transform_y);
-	if (brightness < 7) {
-		brightness = 7;
-	}
+	int x_lo = draw_start_x < 0 ? 0 : draw_start_x;
+	int x_hi = draw_end_x > SCREEN_W ? SCREEN_W : draw_end_x;
+	int y_lo = draw_start_y < 0 ? 0 : draw_start_y;
+	int y_hi = draw_end_y > SCREEN_H ? SCREEN_H : draw_end_y;
 
-	for (int sc = draw_start_x; sc < draw_end_x; sc++) {
-		if (sc < 0 || sc >= SCREEN_W) continue;
-		if (transform_y >= zbuffer[sc]) continue;
+	for (int pass = 0; pass < 2; pass++) {
+		for (int sc = x_lo; sc < x_hi; sc++) {
+			if (transform_y >= zbuffer[sc]) continue;
 
-		int tex_x = (sc - draw_start_x) * 16 / sprite_h;
-		if (tex_x < 0) tex_x = 0;
-		if (tex_x > 15) tex_x = 15;
-
-		for (int sr = draw_start_y; sr < draw_end_y; sr++) {
-			if (sr < 0 || sr >= SCREEN_H) continue;
-
-			int tex_y = (sr - draw_start_y) * 16 / sprite_h;
-			if (tex_y < 0) tex_y = 0;
-			if (tex_y > 15) tex_y = 15;
-
-			if (sprite[tex_y] & (0x8000 >> tex_x)) {
-				uint8_t threshold =
-					bayer4x4[sr & 3][sc & 3];
-				if (brightness > threshold) {
+			for (int sr = y_lo; sr < y_hi; sr++) {
+				if (!sprite_texel_on(sprite, sc, sr,
+						     draw_start_x, draw_start_y,
+						     sprite_w, sprite_h)) {
+					continue;
+				}
+				if (pass == 1) {
 					render_fb[(sr / 8) * SCREEN_W + sc] |=
 						(1U << (sr & 7));
+					continue;
+				}
+				for (int hx = sc - 1; hx <= sc + 1; hx++) {
+					if (hx < 0 || hx >= SCREEN_W ||
+					    transform_y >= zbuffer[hx]) {
+						continue;
+					}
+					for (int hy = sr - 1; hy <= sr + 1; hy++) {
+						if (hy >= 0 && hy < SCREEN_H) {
+							clear_px(hx, hy);
+						}
+					}
 				}
 			}
 		}
@@ -748,7 +778,7 @@ static void render_sprites(void)
 		render_one_sprite(pspr,
 			fp_from_int(game.portal_map_x) + FP_HALF,
 			fp_from_int(game.portal_map_y) + FP_HALF,
-			inv_det, p);
+			inv_det, p, 100);
 	}
 
 	/* Collect visible enemies and sort farthest-first */
@@ -781,7 +811,8 @@ static void render_sprites(void)
 
 	for (int i = 0; i < visible; i++) {
 		struct doom_enemy *e = &game.enemies[order[i].idx];
-		render_one_sprite(get_sprite_16(e), e->x, e->y, inv_det, p);
+		render_one_sprite(get_sprite_16(e), e->x, e->y, inv_det, p,
+				  e->type == ENEMY_BOSS ? 150 : 100);
 	}
 
 	/*
@@ -793,7 +824,7 @@ static void render_sprites(void)
 	for (int i = 0; i < MAX_FIREBALLS; i++) {
 		struct doom_fireball *f = &game.fireballs[i];
 		if (!f->active) continue;
-		render_one_sprite(spr_fireball, f->x, f->y, inv_det, p);
+		render_one_sprite(spr_fireball, f->x, f->y, inv_det, p, 100);
 	}
 }