From 1dfafec5afaf765fa7b44485efee9888aacbfc75 Mon Sep 17 00:00:00 2001
From: Brad Davis <bdavis@saintandreas.org>
Date: Fri, 9 Oct 2015 15:46:54 -0700
Subject: [PATCH] Prototyping controller refactoring

---
 libraries/controllers/CMakeLists.txt          |  14 ++
 .../src/controllers/ControllerMapping.cpp     | 190 ++++++++++++++++++
 2 files changed, 204 insertions(+)
 create mode 100644 libraries/controllers/CMakeLists.txt
 create mode 100644 libraries/controllers/src/controllers/ControllerMapping.cpp

diff --git a/libraries/controllers/CMakeLists.txt b/libraries/controllers/CMakeLists.txt
new file mode 100644
index 0000000000..fbabbe1463
--- /dev/null
+++ b/libraries/controllers/CMakeLists.txt
@@ -0,0 +1,14 @@
+set(TARGET_NAME controllers)
+
+# set a default root dir for each of our optional externals if it was not passed
+setup_hifi_library(Script)
+
+# use setup_hifi_library macro to setup our project and link appropriate Qt modules
+link_hifi_libraries(shared plugins input-plugins)
+
+GroupSources("src/controllers")
+
+add_dependency_external_projects(glm)
+find_package(GLM REQUIRED)
+target_include_directories(${TARGET_NAME} PUBLIC ${GLM_INCLUDE_DIRS})
+
diff --git a/libraries/controllers/src/controllers/ControllerMapping.cpp b/libraries/controllers/src/controllers/ControllerMapping.cpp
new file mode 100644
index 0000000000..59f8789d31
--- /dev/null
+++ b/libraries/controllers/src/controllers/ControllerMapping.cpp
@@ -0,0 +1,190 @@
+#include <map>
+#include <list>
+
+#include <QtCore/QObject>
+#include <QtScript/QScriptValue>
+
+extern float currentTime();
+
+namespace Controllers {
+
+    /*
+    * Encapsulates a particular input / output,
+    * i.e. Hydra.Button0, Standard.X, Action.Yaw
+    */
+    class Endpoint {
+    public:
+        virtual float value() = 0;
+        virtual void apply(float newValue, float oldValue, const Endpoint& source) = 0;
+    };
+
+    using EndpointList = std::list<Endpoint*>;
+
+    const EndpointList& getHardwareEndpoints();
+
+    // Ex: xbox.RY, xbox.A .... 
+    class HardwareEndpoint : public Endpoint {
+    public:
+        virtual float value() override {
+            // ...
+        }
+
+        virtual void apply(float newValue, float oldValue, const Endpoint& source) override {
+            // Default does nothing, but in theory this could be something like vibration
+            // mapping.from(xbox.X).to(xbox.Vibrate)
+        }
+    };
+
+    class VirtualEndpoint : public Endpoint {
+    public:
+        virtual void apply(float newValue) {
+            if (newValue != _lastValue) {
+                _lastValue = newValue;
+            }
+        }
+
+        virtual float value() {
+            return _lastValue;
+        }
+
+        float _lastValue;
+    };
+
+    /*
+    * A function which provides input
+    */
+    class FunctionEndpoint : public Endpoint {
+    public:
+
+        virtual float value() override {
+            float now = currentTime();
+            float delta = now - _lastCalled;
+            float result = _inputFunction.call(_object, QScriptValue(delta)).toNumber();
+            _lastCalled = now;
+            return result;
+        }
+
+        virtual void apply(float newValue, float oldValue, const Endpoint& source) override {
+            if (newValue != oldValue) {
+                //_outputFunction.call(newValue, oldValue, source);
+            }
+        }
+
+        float _lastValue{ NAN };
+        float _lastCalled{ 0 };
+        QScriptValue _outputFunction;
+        QScriptValue _inputFunction;
+        QScriptValue _object;
+    };
+
+
+    // Encapsulates part of a filter chain
+    class Filter {
+    public:
+        virtual float apply(float newValue, float oldValue) = 0;
+    };
+
+    class ScaleFilter : public Filter {
+    public:
+        virtual float apply(float newValue, float oldValue) {
+            return newValue * _scale;
+        }
+
+        float _scale{ 1.0 };
+    };
+
+    class PulseFilter : public Filter {
+    public:
+        virtual float apply(float newValue, float oldValue) {
+            // ???
+        }
+
+        float _lastEmitValue{ 0 };
+        float _lastEmitTime{ 0 };
+        float _interval{ -1.0f };
+    };
+
+    using FilterList = std::list<Filter*>;
+
+    /*
+    * encapsulates a source, destination and filters to apply
+    */
+    class Route {
+    public:
+        Endpoint* _source;
+        Endpoint* _destination;
+        FilterList _filters;
+    };
+
+    using ValueMap = std::map<Endpoint*, float>;
+
+    class Mapping {
+    public:
+        // List of routes
+        using List = std::list<Route>;
+        // Map of source channels to route lists
+        using Map = std::map<Endpoint*, List>;
+
+        Map _channelMappings;
+        ValueMap _lastValues;
+    };
+
+    class MappingsStack {
+        std::list<Mapping> _stack;
+        ValueMap _lastValues;
+
+        void update() {
+            EndpointList hardwareInputs = getHardwareEndpoints();
+            ValueMap currentValues;
+
+            for (auto input : hardwareInputs) {
+                currentValues[input] = input->value();
+            }
+
+            // Now process the current values for each level of the stack
+            for (auto& mapping : _stack) {
+                update(mapping, currentValues);
+            }
+
+            _lastValues = currentValues;
+        }
+
+        void update(Mapping& mapping, ValueMap& values) {
+            ValueMap updates;
+            EndpointList consumedEndpoints;
+            for (const auto& entry : values) {
+                Endpoint* endpoint = entry.first;
+                if (!mapping._channelMappings.count(endpoint)) {
+                    continue;
+                }
+
+                const Mapping::List& routes = mapping._channelMappings[endpoint];
+                consumedEndpoints.push_back(endpoint);
+                for (const auto& route : routes) {
+                    float lastValue = 0;
+                    if (mapping._lastValues.count(endpoint)) {
+                        lastValue = mapping._lastValues[endpoint];
+                    }
+                    float value = entry.second;
+                    for (const auto& filter : route._filters) {
+                        value = filter->apply(value, lastValue);
+                    }
+                    updates[route._destination] = value;
+                }
+            }
+
+            // Update the last seen values
+            mapping._lastValues = values;
+
+            // Remove all the consumed inputs
+            for (auto endpoint : consumedEndpoints) {
+                values.erase(endpoint); 
+            }
+
+            // Add all the updates (may restore some of the consumed data if a passthrough was created (i.e. source == dest)
+            for (const auto& entry : updates) {
+                values[entry.first] = entry.second;
+            }
+        }
+    };
+}