Implemented color triangle calculations.

Author: Tim Niggemann

libsrc/leddevice/LedDevicePhilipsHue.cpp

@@ -10,6 +10,8 @@
 #include <QHttpRequestHeader>
 #include <QEventLoop>
 
+#include <set>
+
 LedDevicePhilipsHue::LedDevicePhilipsHue(const std::string& output) :
 		host(output.c_str()), username("newdeveloper") {
 	http = new QHttp(host);
@@ -24,18 +26,21 @@ LedDevicePhilipsHue::~LedDevicePhilipsHue() {
 
 int LedDevicePhilipsHue::write(const std::vector<ColorRgb> & ledValues) {
 	// Save light states if not done before.
-	if (!statesSaved()) {
-		saveStates(ledValues.size());
-		switchOn(ledValues.size());
+	if (!areStatesSaved()) {
+		saveStates((unsigned int) ledValues.size());
+		switchOn((unsigned int) ledValues.size());
 	}
 	// Iterate through colors and set light states.
 	unsigned int lightId = 1;
 	for (const ColorRgb& color : ledValues) {
-		float x, y, b;
+		// Find triangle.
+		CGTriangle triangle = triangles.at(lightId - 1);
 		// Scale colors from [0, 255] to [0, 1] and convert to xy space.
-		rgbToXYBrightness(color.red / 255.0f, color.green / 255.0f, color.blue / 255.0f, x, y, b);
+		CGPoint xy;
+		float b;
+		rgbToXYBrightness(color.red / 255.0f, color.green / 255.0f, color.blue / 255.0f, triangle, xy, b);
 		// Send adjust color command in JSON format.
-		put(getStateRoute(lightId), QString("{\"xy\": [%1, %2]}").arg(x).arg(y));
+		put(getStateRoute(lightId), QString("{\"xy\": [%1, %2]}").arg(xy.x).arg(xy.y));
 		// Send brightness color command in JSON format.
 		put(getStateRoute(lightId), QString("{\"bri\": %1}").arg(qRound(b * 255.0f)));
 		// Next light id.
@@ -48,7 +53,7 @@ int LedDevicePhilipsHue::write(const std::vector<ColorRgb> & ledValues) {
 int LedDevicePhilipsHue::switchOff() {
 	timer.stop();
 	// If light states have been saved before, ...
-	if (statesSaved()) {
+	if (areStatesSaved()) {
 		// ... restore them.
 		restoreStates();
 	}
@@ -93,6 +98,27 @@ QString LedDevicePhilipsHue::getRoute(unsigned int lightId) {
 	return QString("lights/%1").arg(lightId);
 }
 
+CGTriangle LedDevicePhilipsHue::getTriangle(QString modelId) {
+	const std::set<QString> HUE_BULBS_MODEL_IDS = { "LCT001", "LCT002", "LCT003" };
+	const std::set<QString> LIVING_COLORS_MODEL_IDS = { "LLC001", "LLC005", "LLC006", "LLC007", "LLC011", "LLC012",
+			"LLC013", "LST001" };
+	CGTriangle triangle;
+	if (HUE_BULBS_MODEL_IDS.find(modelId) != HUE_BULBS_MODEL_IDS.end()) {
+		triangle.red = {0.675f, 0.322f};
+		triangle.green = {0.4091f, 0.518f};
+		triangle.blue = {0.167f, 0.04f};
+	} else if (LIVING_COLORS_MODEL_IDS.find(modelId) != LIVING_COLORS_MODEL_IDS.end()) {
+		triangle.red = {0.703f, 0.296f};
+		triangle.green = {0.214f, 0.709f};
+		triangle.blue = {0.139f, 0.081f};
+	} else {
+		triangle.red = {1.0f, 0.0f};
+		triangle.green = {0.0f, 1.0f};
+		triangle.blue = {0.0f, 0.0f};
+	}
+	return triangle;
+}
+
 void LedDevicePhilipsHue::saveStates(unsigned int nLights) {
 	// Clear saved light states.
 	states.clear();
@@ -116,8 +142,12 @@ void LedDevicePhilipsHue::saveStates(unsigned int nLights) {
 			state["xy"] = json["state"]["xy"];
 			state["bri"] = json["state"]["bri"];
 		}
+		// Save id.
+		ids.push_back(QString(writer.write(json["modelid"]).c_str()).trimmed().replace("\"", ""));
 		// Save state object.
 		states.push_back(QString(writer.write(state).c_str()).trimmed());
+		// Determine triangle.
+		triangles.push_back(getTriangle(ids.back()));
 	}
 }
 
@@ -137,27 +167,94 @@ void LedDevicePhilipsHue::restoreStates() {
 	states.clear();
 }
 
-bool LedDevicePhilipsHue::statesSaved() {
+bool LedDevicePhilipsHue::areStatesSaved() {
 	return !states.empty();
 }
 
-void LedDevicePhilipsHue::rgbToXYBrightness(float red, float green, float blue, float& x, float& y, float& brightness) {
+float LedDevicePhilipsHue::crossProduct(CGPoint p1, CGPoint p2) {
+	return p1.x * p2.y - p1.y * p2.x;
+}
+
+bool LedDevicePhilipsHue::isPointInLampsReach(CGTriangle triangle, CGPoint p) {
+	CGPoint v1 = { triangle.green.x - triangle.red.x, triangle.green.y - triangle.red.y };
+	CGPoint v2 = { triangle.blue.x - triangle.red.x, triangle.blue.y - triangle.red.y };
+	CGPoint q = { p.x - triangle.red.x, p.y - triangle.red.y };
+	float s = crossProduct(q, v2) / crossProduct(v1, v2);
+	float t = crossProduct(v1, q) / crossProduct(v1, v2);
+	if ((s >= 0.0f) && (t >= 0.0f) && (s + t <= 1.0f)) {
+		return true;
+	} else {
+		return false;
+	}
+}
+
+CGPoint LedDevicePhilipsHue::getClosestPointToPoint(CGPoint A, CGPoint B, CGPoint P) {
+	CGPoint AP = { P.x - A.x, P.y - A.y };
+	CGPoint AB = { B.x - A.x, B.y - A.y };
+	float ab2 = AB.x * AB.x + AB.y * AB.y;
+	float ap_ab = AP.x * AB.x + AP.y * AB.y;
+	float t = ap_ab / ab2;
+	if (t < 0.0f) {
+		t = 0.0f;
+	} else if (t > 1.0f) {
+		t = 1.0f;
+	}
+	return {A.x + AB.x * t, A.y + AB.y * t};
+}
+
+float LedDevicePhilipsHue::getDistanceBetweenTwoPoints(CGPoint one, CGPoint two) {
+	// Horizontal difference.
+	float dx = one.x - two.x;
+	// Vertical difference.
+	float dy = one.y - two.y;
+	float dist = sqrt(dx * dx + dy * dy);
+	return dist;
+}
+
+void LedDevicePhilipsHue::rgbToXYBrightness(float red, float green, float blue, CGTriangle triangle, CGPoint& xyPoint,
+		float& brightness) {
 	// Apply gamma correction.
-	red = (red > 0.04045f) ? qPow((red + 0.055f) / (1.0f + 0.055f), 2.4f) : (red / 12.92f);
-	green = (green > 0.04045f) ? qPow((green + 0.055f) / (1.0f + 0.055f), 2.4f) : (green / 12.92f);
-	blue = (blue > 0.04045f) ? qPow((blue + 0.055f) / (1.0f + 0.055f), 2.4f) : (blue / 12.92f);
+	float r = (red > 0.04045f) ? powf((red + 0.055f) / (1.0f + 0.055f), 2.4f) : (red / 12.92f);
+	float g = (green > 0.04045f) ? powf((green + 0.055f) / (1.0f + 0.055f), 2.4f) : (green / 12.92f);
+	float b = (blue > 0.04045f) ? powf((blue + 0.055f) / (1.0f + 0.055f), 2.4f) : (blue / 12.92f);
 	// Convert to XYZ space.
-	float X = red * 0.649926f + green * 0.103455f + blue * 0.197109f;
-	float Y = red * 0.234327f + green * 0.743075f + blue * 0.022598f;
-	float Z = red * 0.0000000f + green * 0.053077f + blue * 1.035763f;
+	float X = r * 0.649926f + g * 0.103455f + b * 0.197109f;
+	float Y = r * 0.234327f + g * 0.743075f + b * 0.022598f;
+	float Z = r * 0.0000000f + g * 0.053077f + b * 1.035763f;
 	// Convert to x,y space.
-	x = X / (X + Y + Z);
-	y = Y / (X + Y + Z);
-	if (isnan(x)) {
-		x = 0.0f;
+	float cx = X / (X + Y + Z + 0.0000001f);
+	float cy = Y / (X + Y + Z + 0.0000001f);
+	if (isnan(cx)) {
+		cx = 0.0f;
+	}
+	if (isnan(cy)) {
+		cy = 0.0f;
 	}
-	if (isnan(y)) {
-		y = 0.0f;
+	xyPoint.x = cx;
+	xyPoint.y = cy;
+	// Check if the given XY value is within the colourreach of our lamps.
+	if (!isPointInLampsReach(triangle, xyPoint)) {
+		// It seems the colour is out of reach let's find the closes colour we can produce with our lamp and send this XY value out.
+		CGPoint pAB = getClosestPointToPoint(triangle.red, triangle.green, xyPoint);
+		CGPoint pAC = getClosestPointToPoint(triangle.blue, triangle.red, xyPoint);
+		CGPoint pBC = getClosestPointToPoint(triangle.green, triangle.blue, xyPoint);
+		// Get the distances per point and see which point is closer to our Point.
+		float dAB = getDistanceBetweenTwoPoints(xyPoint, pAB);
+		float dAC = getDistanceBetweenTwoPoints(xyPoint, pAC);
+		float dBC = getDistanceBetweenTwoPoints(xyPoint, pBC);
+		float lowest = dAB;
+		CGPoint closestPoint = pAB;
+		if (dAC < lowest) {
+			lowest = dAC;
+			closestPoint = pAC;
+		}
+		if (dBC < lowest) {
+			lowest = dBC;
+			closestPoint = pBC;
+		}
+		// Change the xy value to a value which is within the reach of the lamp.
+		xyPoint.x = closestPoint.x;
+		xyPoint.y = closestPoint.y;
 	}
 	// Brightness is simply Y in the XYZ space.
 	brightness = Y;

libsrc/leddevice/LedDevicePhilipsHue.h

@@ -12,6 +12,15 @@
 // Leddevice includes
 #include <leddevice/LedDevice.h>
 
+struct CGPoint {
+	float x;
+	float y;
+};
+
+struct CGTriangle {
+	CGPoint red, green, blue;
+};
+
 /**
  * Implementation for the Philips Hue system.
  *
@@ -56,6 +65,10 @@ private slots:
 private:
 	/// Array to save the light states.
 	std::vector<QString> states;
+	/// Array to save model ids.
+	std::vector<QString> ids;
+	/// Color triangles.
+	std::vector<CGTriangle> triangles;
 	/// Ip address of the bridge
 	QString host;
 	/// User name for the API ("newdeveloper")
@@ -114,7 +127,7 @@ private slots:
 	///
 	/// @return true if light states have been saved.
 	///
-	bool statesSaved();
+	bool areStatesSaved();
 
 	///
 	/// Converts an RGB color to the Hue xy color space and brightness
@@ -126,12 +139,16 @@ private slots:
 	///
 	/// @param blue the blue component in [0, 1]
 	///
-	/// @param x converted x component
-	///
-	/// @param y converted y component
+	/// @param xyPoint converted xy component
 	///
 	/// @param brightness converted brightness component
 	///
-	void rgbToXYBrightness(float red, float green, float blue, float& x, float& y, float& brightness);
+	void rgbToXYBrightness(float red, float green, float blue, CGTriangle triangle, CGPoint& xyPoint, float& brightness);
+
+	CGTriangle getTriangle(QString modelId);
+	float crossProduct(CGPoint p1, CGPoint p2);
+	bool isPointInLampsReach(CGTriangle triangle, CGPoint p);
+	CGPoint getClosestPointToPoint(CGPoint a, CGPoint b, CGPoint p);
+	float getDistanceBetweenTwoPoints(CGPoint one, CGPoint two);
 
 };