@@ -322,6 +322,7 @@ void GBAGPIOInitLightSensor(struct GBACartridgeGPIO* gpio) {
 	gpio->gpioDevices |= GPIO_LIGHT_SENSOR;
 	gpio->lightCounter = 0;
 	gpio->lightEdge = false;
+	gpio->lightSample = 0xFF;
 }
 
 void _lightReadPins(struct GBACartridgeGPIO* gpio) {
@@ -330,15 +331,22 @@ // Boktai chip select
 		return;
 	}
 	if (gpio->p1) {
+		struct GBALuminanceSource* lux = gpio->p->luminanceSource;
 		GBALog(0, GBA_LOG_DEBUG, "[SOLAR] Got reset");
 		gpio->lightCounter = 0;
+		if (lux) {
+			lux->sample(lux);
+			gpio->lightSample = lux->readLuminance(lux);
+		} else {
+			gpio->lightSample = 0xFF;
+		}
 	}
 	if (gpio->p0 && gpio->lightEdge) {
 		++gpio->lightCounter;
 	}
 	gpio->lightEdge = !gpio->p0;
 
-	bool sendBit = gpio->lightCounter >= 0x80;
+	bool sendBit = gpio->lightCounter >= gpio->lightSample;
 	_outputPins(gpio, sendBit << 3);
 	GBALog(0, GBA_LOG_DEBUG, "[SOLAR] Output %u with pins %u", gpio->lightCounter, gpio->pinState);
 }

@@ -104,7 +104,8 @@
 	uint16_t gyroSample;
 	bool gyroEdge;
 
-	int lightCounter : 12;
+	unsigned lightCounter : 12;
+	uint8_t lightSample;
 	bool lightEdge;
 };
 

@@ -17,4 +17,10 @@
 	int32_t (*readGyroZ)(struct GBARotationSource*);
 };
 
+struct GBALuminanceSource {
+	void (*sample)(struct GBALuminanceSource*);
+
+	uint8_t (*readLuminance)(struct GBALuminanceSource*);
+};
+
 #endif

@@ -732,6 +732,10 @@ if (_overrides[i].gpio & GPIO_RUMBLE) {
 				GBAGPIOInitRumble(&gba->memory.gpio);
 			}
 
+			if (_overrides[i].gpio & GPIO_LIGHT_SENSOR) {
+				GBAGPIOInitLightSensor(&gba->memory.gpio);
+			}
+
 			gba->busyLoop = _overrides[i].busyLoop;
 			return;
 		}

@@ -115,7 +115,9 @@ uint32_t biosChecksum;
 	int* keySource;
 	uint32_t busyLoop;
 	struct GBARotationSource* rotationSource;
+	struct GBALuminanceSource* luminanceSource;
 	struct GBARumble* rumble;
+
 	struct GBARRContext* rr;
 	void* pristineRom;
 	size_t pristineRomSize;