From 7f2ada6982c6313fffc4ad5889ff5b635cd27163 Mon Sep 17 00:00:00 2001
From: falsycat <me@falsy.cat>
Date: Wed, 9 Oct 2019 00:00:00 +0000
Subject: [PATCH] [update] Implemented player's moving calculation.

---
 sjplayer/src/sjplayer/Actor.d           | 18 +++++++++---------
 sjplayer/src/sjplayer/ActorController.d | 24 +++++++++++++++++++-----
 sjplayer/standalone/main.d              | 19 +++++++++++++++++++
 3 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/sjplayer/src/sjplayer/Actor.d b/sjplayer/src/sjplayer/Actor.d
index 2bdf5dd..299e023 100644
--- a/sjplayer/src/sjplayer/Actor.d
+++ b/sjplayer/src/sjplayer/Actor.d
@@ -9,7 +9,7 @@ class Actor {
   ///
   this(ActorProgram program) {
     pos   = vec2(0, 0);
-    accel = vec2(0, 0);
+    speed = vec2(0, 0);
     color = vec4(0, 0, 0, 0);
 
     program_ = program;
@@ -17,11 +17,11 @@ class Actor {
 
   ///
   void Draw() {
-    program_.Draw(pos, accel, color);
+    program_.Draw(pos, speed, color);
   }
 
   vec2 pos;
-  vec2 accel;
+  vec2 speed;
   vec4 color;
 
  private:
@@ -49,22 +49,22 @@ class ActorProgram {
   ///
   enum FragmentShaderSrc = ShaderHeader ~ q{
     layout(location = 0) uniform vec2 pos;
-    layout(location = 1) uniform vec2 accel;
+    layout(location = 1) uniform vec2 speed;
     layout(location = 2) uniform vec4 color;
 
     in vec2  uv_;
 
     out vec4 pixel_;
 
-    float line(float u, float p, float a) {
+    float line(float u, float p, float s) {
       return
         (1-smoothstep(0, 0.003, abs(u-p)));
     }
 
     void main() {
       float alpha =
-        line(uv_.x, pos.x, accel.x) +
-        line(uv_.y, pos.y, accel.y);
+        line(uv_.x, pos.x, speed.x) +
+        line(uv_.y, pos.y, speed.y);
       pixel_    = color;
       pixel_.a *= clamp(alpha, 0, 1);
     }
@@ -102,10 +102,10 @@ class ActorProgram {
   }
 
   ///
-  void Draw(vec2 pos, vec2 accel, vec4 color) {
+  void Draw(vec2 pos, vec2 speed, vec4 color) {
     program_.Use();
     program_.uniform!0 = pos;
-    program_.uniform!1 = accel;
+    program_.uniform!1 = speed;
     program_.uniform!2 = color;
 
     vao_.Bind();
diff --git a/sjplayer/src/sjplayer/ActorController.d b/sjplayer/src/sjplayer/ActorController.d
index c62f59b..427076a 100644
--- a/sjplayer/src/sjplayer/ActorController.d
+++ b/sjplayer/src/sjplayer/ActorController.d
@@ -19,7 +19,11 @@ import sjplayer.AbstractScheduledController,
 class ActorController : ActorScheduledController, ActorControllerInterface {
  public:
   ///
-  enum MaxAccel = 1e-1;
+  enum AccelAdjustment = 0.005;
+  ///
+  enum MaxSpeed = 0.03;
+  ///
+  enum SpeedAttenuation = 0.05;
 
   ///
   this(
@@ -30,17 +34,25 @@ class ActorController : ActorScheduledController, ActorControllerInterface {
     actor_      = actor;
     varstore_   = varstore;
     operations_ = operations;
+
+    accel_ = vec2(0, 0);
   }
 
   override void Accelarate(vec2 accel) {
-    actor_.accel += accel;
+    accel_ = accel * AccelAdjustment;
   }
   override void Update() {
-    actor_.accel.x = actor_.accel.x.clamp(-MaxAccel, MaxAccel);
-    actor_.accel.y = actor_.accel.y.clamp(-MaxAccel, MaxAccel);
+    actor_.speed += accel_;
 
-    actor_.pos += actor_.accel;
+    const speed_length = actor_.speed.length;
+    if (speed_length > MaxSpeed) {
+      actor_.speed = actor_.speed / speed_length * MaxSpeed;
+    }
+
+    actor_.pos += actor_.speed;
     // TODO: clamping the actor position
+
+    actor_.speed *= 1-SpeedAttenuation;
   }
 
  private:
@@ -49,6 +61,8 @@ class ActorController : ActorScheduledController, ActorControllerInterface {
   const VarStoreInterface varstore_;
 
   const ParametersBlock[] operations_;
+
+  vec2 accel_;
 }
 
 private alias ActorScheduledController = ScheduledController!(
diff --git a/sjplayer/standalone/main.d b/sjplayer/standalone/main.d
index ac124f2..c95ebea 100644
--- a/sjplayer/standalone/main.d
+++ b/sjplayer/standalone/main.d
@@ -37,6 +37,8 @@ int main(string[] args) {
     const msecs = sfMusic_getPlayingOffset(music).microseconds * 1e-6f;
     const beat  = msecs/60f * bpm;
 
+    context.actor.Accelarate(GetAccelarationInput());
+
     context.OperateScheduledControllers(beat);
     context.actor.Update();
     context.posteffect.Update();
@@ -53,6 +55,23 @@ int main(string[] args) {
   return 0;
 }
 
+vec2 GetAccelarationInput() {
+  auto result = vec2(0, 0);
+  if (sfKeyboard_isKeyPressed(sfKeyLeft)) {
+    result.x -= 1;
+  }
+  if (sfKeyboard_isKeyPressed(sfKeyRight)) {
+    result.x += 1;
+  }
+  if (sfKeyboard_isKeyPressed(sfKeyUp)) {
+    result.y += 1;
+  }
+  if (sfKeyboard_isKeyPressed(sfKeyDown)) {
+    result.y -= 1;
+  }
+  return result;
+}
+
 sfWindow* Initialize() {
   DerelictSFML2System.load();
   DerelictSFML2Window.load();