animate northing

.gitignore

@@ -1,3 +1,6 @@
 *.o
 /emscripten/main.js
-/emscripten/main.js.map
+/emscripten/main.js.map
+/build
+/xcode
+*.sublime-*

include/llmr/map/transform.hpp

@@ -1,9 +1,12 @@
 #ifndef LLMR_MAP_TRANSFORM
 #define LLMR_MAP_TRANSFORM
 
-#include <cstdint>
 
 #include <llmr/util/vec2.hpp>
+#include <llmr/util/animation.hpp>
+
+#include <cstdint>
+#include <forward_list>
 
 namespace llmr {
 
@@ -15,6 +18,10 @@ class transform {
 public:
     transform();
 
+    // Animations
+    bool needsAnimation() const;
+    void updateAnimations();
+
     // Relative changes
     void moveBy(double dx, double dy);
     void scaleBy(double ds, double cx, double cy);
@@ -22,7 +29,7 @@ public:
 
     // Absolute changes
     void setScale(double scale);
-    void setAngle(double angle);
+    void setAngle(double angle, double duration = 0);
     void setZoom(double zoom);
     void setLonLat(double lon, double lat);
 
@@ -58,6 +65,8 @@ private:
 
     // cache values for spherical mercator math
     double zc, Bc, Cc;
+
+    std::forward_list<util::animation> animations;
 };
 
 }

include/llmr/platform/platform.hpp

@@ -11,6 +11,7 @@ namespace platform {
 
 void restart(void *obj);
 void request(void *obj, std::shared_ptr<tile> tile);
+double time();
 
 }
 

include/llmr/util/animation.hpp

@@ -0,0 +1,30 @@
+#ifndef LLMR_UTIL_ANIMATION
+#define LLMR_UTIL_ANIMATION
+
+namespace llmr {
+namespace util {
+
+class animation {
+public:
+    enum state {
+        running,
+        complete
+    };
+
+    animation(double from, double to, double &value, double duration);
+    animation(const animation &) = delete;
+    animation(const animation &&) = delete;
+    animation &operator=(const animation &) = delete;
+
+    state update() const;
+
+private:
+    const double start, duration;
+    const double from, to;
+    double &value;
+};
+
+}
+}
+
+#endif

include/llmr/util/unitbezier.hpp

@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2008 Apple Inc. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef LLMR_UTIL_UNITBEZIER
+#define LLMR_UTIL_UNITBEZIER
+
+#include <cmath>
+
+namespace llmr {
+namespace util {
+
+struct UnitBezier {
+    UnitBezier(double p1x, double p1y, double p2x, double p2y) {
+        // Calculate the polynomial coefficients, implicit first and last control points are (0,0) and (1,1).
+        cx = 3.0 * p1x;
+        bx = 3.0 * (p2x - p1x) - cx;
+        ax = 1.0 - cx - bx;
+
+        cy = 3.0 * p1y;
+        by = 3.0 * (p2y - p1y) - cy;
+        ay = 1.0 - cy - by;
+    }
+
+    double sampleCurveX(double t) {
+        // `ax t^3 + bx t^2 + cx t' expanded using Horner's rule.
+        return ((ax * t + bx) * t + cx) * t;
+    }
+
+    double sampleCurveY(double t) {
+        return ((ay * t + by) * t + cy) * t;
+    }
+
+    double sampleCurveDerivativeX(double t) {
+        return (3.0 * ax * t + 2.0 * bx) * t + cx;
+    }
+
+    // Given an x value, find a parametric value it came from.
+    double solveCurveX(double x, double epsilon) {
+        double t0;
+        double t1;
+        double t2;
+        double x2;
+        double d2;
+        int i;
+
+        // First try a few iterations of Newton's method -- normally very fast.
+        for (t2 = x, i = 0; i < 8; i++) {
+            x2 = sampleCurveX(t2) - x;
+            if (fabs (x2) < epsilon)
+                return t2;
+            d2 = sampleCurveDerivativeX(t2);
+            if (fabs(d2) < 1e-6)
+                break;
+            t2 = t2 - x2 / d2;
+        }
+
+        // Fall back to the bisection method for reliability.
+        t0 = 0.0;
+        t1 = 1.0;
+        t2 = x;
+
+        if (t2 < t0)
+            return t0;
+        if (t2 > t1)
+            return t1;
+
+        while (t0 < t1) {
+            x2 = sampleCurveX(t2);
+            if (fabs(x2 - x) < epsilon)
+                return t2;
+            if (x > x2)
+                t0 = t2;
+            else
+                t1 = t2;
+            t2 = (t1 - t0) * .5 + t0;
+        }
+
+        // Failure.
+        return t2;
+    }
+
+    double solve(double x, double epsilon) {
+        return sampleCurveY(solveCurveX(x, epsilon));
+    }
+
+private:
+    double ax;
+    double bx;
+    double cx;
+
+    double ay;
+    double by;
+    double cy;
+};
+
+}
+}
+
+#endif

macosx/main.mm

@@ -255,6 +255,10 @@ void request(void *, tile::ptr tile) {
     }];
 }
 
+double time() {
+    return glfwGetTime();
+}
+
 }
 }
 

src/CMakeLists.txt

@@ -9,6 +9,7 @@ SET(llmr_SOURCES
     renderer/shader-line.cpp
     renderer/shader.cpp
     shader/shaders.c
+    util/animation.cpp
     util/mat4.c
 )
 
@@ -25,6 +26,7 @@ SET(llmr_HEADERS
     ../include/llmr/renderer/shader-fill.hpp
     ../include/llmr/renderer/shader-line.hpp
     ../include/llmr/renderer/shader.hpp
+    ../include/llmr/util/animation.hpp
     ../include/llmr/util/math.hpp
     ../include/llmr/util/vec2.hpp
 )

src/map/map.cpp

@@ -65,7 +65,7 @@ void map::rotateBy(double cx, double cy, double sx, double sy, double ex, double
 }
 
 void map::resetNorth() {
-    transform->setAngle(0);
+    transform->setAngle(0, 0.5); // 500 ms
     update();
 
     settings->angle = transform->getAngle();
@@ -261,6 +261,8 @@ void map::updateTiles() {
 }
 
 bool map::render() {
+    transform->updateAnimations();
+
     painter->clear();
 
     for (tile::ptr& tile : tiles) {
@@ -270,7 +272,7 @@ bool map::render() {
         }
     }
 
-    return false;
+    return transform->needsAnimation();
 }
 
 void map::tileLoaded(tile::ptr tile) {

src/map/transform.cpp

@@ -1,5 +1,4 @@
 #include <llmr/map/transform.hpp>
-
 #include <llmr/util/mat4.h>
 #include <llmr/util/math.hpp>
 #include <cmath>
@@ -29,6 +28,16 @@ transform::transform()
     setAngle(angle);
 }
 
+bool transform::needsAnimation() const {
+    return !animations.empty();
+}
+
+void transform::updateAnimations() {
+    animations.remove_if([](const util::animation& animation) {
+        return animation.update() == util::animation::complete;
+    });
+}
+
 void transform::moveBy(double dx, double dy) {
     x += cos(angle) * dx + sin(angle) * dy;
     y += cos(angle) * dy + sin(-angle) * dx;
@@ -82,10 +91,15 @@ void transform::rotateBy(double anchor_x, double anchor_y, double start_x, doubl
     setAngle(ang);
 }
 
-void transform::setAngle(double new_angle) {
-    angle = new_angle;
-    while (angle > M_PI) angle -= M2PI;
-    while (angle <= -M_PI) angle += M2PI;
+void transform::setAngle(double new_angle, double duration) {
+    while (new_angle > M_PI) new_angle -= M2PI;
+    while (new_angle <= -M_PI) new_angle += M2PI;
+
+    if (duration == 0) {
+        angle = new_angle;
+    } else {
+        animations.emplace_front(angle, new_angle, angle, duration);
+    }
 }
 
 void transform::setScale(double new_scale) {

src/util/animation.cpp

@@ -0,0 +1,26 @@
+#include <llmr/util/animation.hpp>
+#include <llmr/util/unitbezier.hpp>
+#include <llmr/platform/platform.hpp>
+
+using namespace llmr::util;
+
+UnitBezier ease(0.25, 0.1, 0.25, 1);
+
+animation::animation(double from, double to, double &value, double duration)
+    : start(platform::time()),
+      duration(duration),
+      from(from),
+      to(to),
+      value(value) {
+}
+
+animation::state animation::update() const {
+    double t = (platform::time() - start) / duration;
+    if (t >= 1) {
+        value = to;
+        return complete;
+    } else {
+        value = from + (to - from) * ease.solve(t, 0.001);
+        return running;
+    }
+}