Improve deadzone algorithm and use it for SDL_GameController, fix #111

jhasse · Jan 27, 2025 · 9aee239 · 9aee239
1 parent 008f3bd
commit 9aee239
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Showing 2 changed files with 20 additions and 4 deletions.
diff --git a/src/sdl/controller/SdlController.cpp b/src/sdl/controller/SdlController.cpp
@@ -122,12 +122,26 @@ float SdlController::stateImpl(controller::Button button) const {
 		otherState *= std::sqrt(1 - 0.5 * state * state);
 		state = static_cast<float>(tmp);
 	}
-	if (model != Model::XBOX_WIRED && model != Model::XBOX) {
+	if (!gameController && model != Model::XBOX_WIRED && model != Model::XBOX) {
 		return state; // no deadzone needed
 	}
-	if (state * state + otherState * otherState < 0.1) { // inside deadzone circle?
+	const auto lengthSquared = state * state + otherState * otherState;
+	const float DEADZONE_RADIUS = 0.2;
+	if (lengthSquared < DEADZONE_RADIUS * DEADZONE_RADIUS) { // inside deadzone circle?
 		return 0;
 	}
+
+	// smooth out transition out of deadzone to 2 * deadzone:
+	if (lengthSquared < DEADZONE_RADIUS * 2 * DEADZONE_RADIUS * 2) {
+		float directionVectorInDeadzone = state / std::sqrt(lengthSquared) * DEADZONE_RADIUS;
+		return (state - directionVectorInDeadzone) * 2;
+	}
+
+	// not a perfect square, but most controllers are returning coordinates outside of a circle:
+	if (lengthSquared > 1) {
+		return state / std::sqrt(lengthSquared);
+	}
+
 	return state;
 }
 

diff --git a/src/test/test.cpp b/src/test/test.cpp
@@ -513,8 +513,10 @@ void testKeys() {
 				auto circleModelview = jngl::modelview().translate(
 				    { 530, static_cast<double>(-40 + controllerNr * 110) });
 				jngl::drawEllipse(circleModelview, circleRadius, circleRadius);
-				jngl::setColor(255, 255, 255, 255);
-				jngl::drawCircle(circleModelview.translate(circleRadius * stick), 4);
+				const double length = boost::qvm::mag(stick);
+				jngl::drawCircle(circleModelview.translate(circleRadius * stick), 4,
+				                 length > 1 ? jngl::Rgba(1, 2 - length, 2 - length, 1)
+				                            : 0xffffffff_rgba);
 				jngl::translate(0, 2 * circleRadius + 10);
 			}