animate northing

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;
+    }
+}