added new sanity checks and compile-time assertions to prevent errors

fixed stair-building issue
new test-cases
added elevator support
fixed/improved some walker modules

grid/walk/v2/modules/WalkModuleHeading.h

@@ -4,10 +4,52 @@
 #include "WalkModule.h"
 #include "WalkStateHeading.h"
 
+#include "../../../../Assertions.h"
+
 #include "../../../../geo/Heading.h"
 #include "../../../../math/Distributions.h"
 
 
+#include "../../../../geo/Heading.h"
+
+/**
+ * base-class e.g. needed for GridWalkHeading and GridWalkHeadingControl to work
+ */
+struct WalkStateHeading {
+
+	/** used for better naming: heading.error instead of headingError */
+	struct _Heading {
+
+		/**
+		 * the direction [0:2pi] the walk should move to
+		 * e.g. indiciated by:
+		 *		compass
+		 *		integration over gyroscope values
+		 */
+		Heading direction;
+
+		/**
+		 * (cumulative) error between walked edges and requested direction (above).
+		 * is used to ensure that (even though the grid contains only 45° edges) we
+		 * approximately walk into the requested direction.
+		 */
+		float error = 0;
+
+		/** ctor */
+		_Heading(const Heading direction, const float error) : direction(direction), error(error) {;}
+
+	} heading;
+
+
+
+
+	/** ctor */
+	explicit WalkStateHeading(const Heading& direction, const float error) : heading(direction, error) {;}
+
+};
+
+
+
 /** keep the state's heading */
 template <typename Node, typename WalkState> class WalkModuleHeading : public WalkModule<Node, WalkState> {
 
@@ -23,7 +65,10 @@ public:
 
 	/** ctor */
 	WalkModuleHeading() : dist(Distribution::VonMises<double>(0.0f, 1.0f).getLUT()), draw(dist.getDrawList()) {
-		;
+
+		// ensure the template WalkState inherits from 'WalkStateHeading'!
+		StaticAssert::AinheritsB<WalkState, WalkStateHeading>();
+
 	}
 
 	virtual void updateBefore(WalkState& state) override {