First pass at Rig timeScaling and blending between slow, walk and run.

interface/resources/meshes/defaultAvatar_full/avatar-animation.json

@@ -4,7 +4,7 @@
         "id": "ikOverlay",
         "type": "overlay",
         "data": {
-            "alpha": 1.0,
+            "alpha": 0.0,
             "boneSet": "fullBody"
         },
         "children": [
@@ -532,7 +532,8 @@
                                                     "alpha": 0.0,
                                                     "sync": true,
                                                     "timeScale": 1.0,
-                                                    "timeScaleVar": "walkTimeScale"
+                                                    "timeScaleVar": "walkTimeScale",
+                                                    "alphaVar": "walkAlpha"
                                                 },
                                                 "children": [
                                                     {
@@ -558,6 +559,18 @@
                                                             "loopFlag": true
                                                         },
                                                         "children": []
+                                                    },
+                                                    {
+                                                        "id": "walkFwdRun",
+                                                        "type": "clip",
+                                                        "data": {
+                                                            "url": "https://hifi-public.s3.amazonaws.com/ozan/anim/standard_anims/run_fwd.fbx",
+                                                            "startFrame": 0.0,
+                                                            "endFrame": 21.0,
+                                                            "timeScale": 1.0,
+                                                            "loopFlag": true
+                                                        },
+                                                        "children": []
                                                     }
                                                 ]
                                             },

libraries/animation/src/Rig.cpp

@@ -408,6 +408,41 @@ glm::mat4 Rig::getJointTransform(int jointIndex) const {
     return _jointStates[jointIndex].getTransform();
 }
 
+void Rig::calcWalkForwardAlphaAndTimeScale(float speed, float* alphaOut, float* timeScaleOut) {
+
+    // filter speed using a moving average.
+    _averageForwardSpeed.updateAverage(speed);
+    speed = _averageForwardSpeed.getAverage();
+
+    const int NUM_FWD_SPEEDS = 3;
+    float FWD_SPEEDS[NUM_FWD_SPEEDS] = { 0.3f, 1.4f, 2.7f }; // m/s
+
+    // first calculate alpha by lerping between speeds.
+    float alpha = 0.0f;
+    if (speed <= FWD_SPEEDS[0]) {
+        alpha = 0.0f;
+    } else if (speed > FWD_SPEEDS[NUM_FWD_SPEEDS - 1]) {
+        alpha = (float)(NUM_FWD_SPEEDS - 1);
+    } else {
+        for (int i = 0; i < NUM_FWD_SPEEDS - 1; i++) {
+            if (FWD_SPEEDS[i] < speed && speed < FWD_SPEEDS[i + 1]) {
+                alpha = (float)i + ((speed - FWD_SPEEDS[i]) / (FWD_SPEEDS[i + 1] - FWD_SPEEDS[i]));
+                break;
+            }
+        }
+    }
+
+    // now keeping the alpha fixed compute the timeScale.
+    // NOTE: This makes the assumption that the velocity of a linear blend between two animations is also linear.
+    int prevIndex = glm::floor(alpha);
+    int nextIndex = glm::ceil(alpha);
+    float animSpeed = lerp(FWD_SPEEDS[prevIndex], FWD_SPEEDS[nextIndex], (float)glm::fract(alpha));
+    float timeScale = glm::clamp(0.5f, 2.0f, speed / animSpeed);
+
+    *alphaOut = alpha;
+    *timeScaleOut = timeScale;
+}
+
 void Rig::computeMotionAnimationState(float deltaTime, const glm::vec3& worldPosition, const glm::vec3& worldVelocity, const glm::quat& worldRotation) {
 
     glm::vec3 front = worldRotation * IDENTITY_FRONT;
@@ -435,10 +470,13 @@ void Rig::computeMotionAnimationState(float deltaTime, const glm::vec3& worldPos
 
         // sine wave LFO var for testing.
         static float t = 0.0f;
-        _animVars.set("sine", static_cast<float>(0.5 * sin(t) + 0.5));
+        _animVars.set("sine", 2.0f * static_cast<float>(0.5 * sin(t) + 0.5));
 
-        const float ANIM_WALK_SPEED = 1.4f; // m/s
+        float walkAlpha, walkTimeScale;
-        _animVars.set("walkTimeScale", glm::clamp(0.5f, 2.0f, glm::length(localVel) / ANIM_WALK_SPEED));
+        calcWalkForwardAlphaAndTimeScale(glm::length(localVel), &walkAlpha, &walkTimeScale);
+
+        _animVars.set("walkTimeScale", walkTimeScale);
+        _animVars.set("walkAlpha", walkAlpha);
 
         const float MOVE_ENTER_SPEED_THRESHOLD = 0.2f; // m/sec
         const float MOVE_EXIT_SPEED_THRESHOLD = 0.07f;  // m/sec

libraries/animation/src/Rig.h

@@ -42,6 +42,7 @@
 
 #include "AnimNode.h"
 #include "AnimNodeLoader.h"
+#include "SimpleMovingAverage.h"
 
 class AnimationHandle;
 typedef std::shared_ptr<AnimationHandle> AnimationHandlePointer;
@@ -206,6 +207,7 @@ public:
     void updateLeanJoint(int index, float leanSideways, float leanForward, float torsoTwist);
     void updateNeckJoint(int index, const HeadParameters& params);
     void updateEyeJoint(int index, const glm::vec3& modelTranslation, const glm::quat& modelRotation, const glm::quat& worldHeadOrientation, const glm::vec3& lookAt, const glm::vec3& saccade);
+    void calcWalkForwardAlphaAndTimeScale(float speed, float* alphaOut, float* timeScaleOut);
 
     QVector<JointState> _jointStates;
     int _rootJointIndex = -1;
@@ -240,6 +242,8 @@ public:
     float _desiredStateAge = 0.0f;
     float _leftHandOverlayAlpha = 0.0f;
     float _rightHandOverlayAlpha = 0.0f;
+
+    SimpleMovingAverage _averageForwardSpeed{ 25 };
 };
 
 #endif /* defined(__hifi__Rig__) */

libraries/shared/src/GLMHelpers.h

@@ -183,6 +183,11 @@ T toNormalizedDeviceScale(const T& value, const T& size) {
 #define PITCH(euler) euler.x
 #define ROLL(euler) euler.z
 
+// float - linear interpolate
+inline float lerp(float x, float y, float a) {
+    return x * (1.0f - a) + (y * a);
+}
+
 // vec2 lerp - linear interpolate
 template<typename T, glm::precision P>
 glm::detail::tvec2<T, P> lerp(const glm::detail::tvec2<T, P>& x, const glm::detail::tvec2<T, P>& y, T a) {