From 32a80bf865ea61f9abba6295abb33577002f93aa Mon Sep 17 00:00:00 2001
From: falsycat <me@falsy.cat>
Date: Tue, 8 Oct 2019 00:00:00 +0000
Subject: [PATCH] [add] Added Actor.

---
 sjplayer/src/sjplayer/Actor.d      | 119 +++++++++++++++++++++++++++++
 sjplayer/src/sjplayer/ProgramSet.d |   4 +-
 2 files changed, 122 insertions(+), 1 deletion(-)
 create mode 100644 sjplayer/src/sjplayer/Actor.d

diff --git a/sjplayer/src/sjplayer/Actor.d b/sjplayer/src/sjplayer/Actor.d
new file mode 100644
index 0000000..6862f5b
--- /dev/null
+++ b/sjplayer/src/sjplayer/Actor.d
@@ -0,0 +1,119 @@
+/// License: MIT
+module sjplayer.Actor;
+
+import gl4d;
+
+///
+class Actor {
+ public:
+  ///
+  this(ActorProgram program) {
+    pos   = vec2(0, 0);
+    accel = vec2(0, 0);
+    color = vec4(0, 0, 0, 0);
+
+    program_ = program;
+  }
+
+  ///
+  void Draw() {
+    program_.Draw(pos, accel, color);
+  }
+
+  vec2 pos;
+  vec2 accel;
+  vec4 color;
+
+ private:
+  ActorProgram program_;
+}
+
+///
+class ActorProgram {
+ public:
+  ///
+  enum ShaderHeader = "#version 330 core
+#extension GL_ARB_explicit_uniform_location : enable";
+
+  ///
+  enum VertexShaderSrc = ShaderHeader ~ q{
+    layout(location = 0) in vec2 vert;
+
+    out vec2 uv_;
+
+    void main() {
+      uv_         = vert;
+      gl_Position = vec4(vert, 0, 1);
+    }
+  };
+  ///
+  enum FragmentShaderSrc = ShaderHeader ~ q{
+    layout(location = 0) uniform vec2 pos;
+    layout(location = 1) uniform vec2 accel;
+    layout(location = 2) uniform vec4 color;
+
+    in vec2  uv_;
+
+    out vec4 pixel_;
+
+    float line(float ux, float px, float a) {
+      return
+        (1 - smoothstep(0, 0.003, abs(ux - px)));
+    }
+
+    void main() {
+      pixel_    = color;
+      pixel_.a *=
+        clamp(0, 1, line(uv_.y, pos.y, accel.y) + line(uv_.x, pos.x, accel.x));
+    }
+  };
+
+  ///
+  this() {
+    ProgramLinker linker;
+    linker.vertex   = VertexShader.Compile(VertexShaderSrc);
+    linker.fragment = FragmentShader.Compile(FragmentShaderSrc);
+    program_ = linker.Link();
+    program_.Validate();
+
+    vao_   = VertexArray.Create();
+    verts_ = ArrayBuffer.Create();
+
+    vao_.Bind();
+    VertexArrayAttacher attacher;
+    with (attacher) {
+      index     = 0;
+      type      = GL_FLOAT;
+      dimension = 2;
+      Attach(vao_, verts_);
+    }
+
+    verts_.Bind();
+    ArrayBufferAllocator verts_allocator;
+    with (verts_allocator) {
+      const v = [vec2(-1, 1), vec2(1, 1), vec2(1, -1), vec2(-1, -1),];
+      data  = v.ptr;
+      size  = typeof(v[0]).sizeof * v.length;
+      usage = GL_STATIC_DRAW;
+      Allocate(verts_);
+    }
+  }
+
+  ///
+  void Draw(vec2 pos, vec2 accel, vec4 color) {
+    program_.Use();
+    program_.uniform!0 = pos;
+    program_.uniform!1 = accel;
+    program_.uniform!2 = color;
+
+    vao_.Bind();
+    gl.DrawArrays(GL_TRIANGLE_FAN, 0, 4);
+  }
+
+ private:
+  ProgramRef program_;
+
+  ArrayBufferRef verts_;
+
+  VertexArrayRef vao_;
+}
diff --git a/sjplayer/src/sjplayer/ProgramSet.d b/sjplayer/src/sjplayer/ProgramSet.d
index 2392fa5..7225c60 100644
--- a/sjplayer/src/sjplayer/ProgramSet.d
+++ b/sjplayer/src/sjplayer/ProgramSet.d
@@ -4,7 +4,8 @@ module sjplayer.ProgramSet;
 import std.meta,
        std.typecons;
 
-import sjplayer.Background,
+import sjplayer.Actor,
+       sjplayer.Background,
        sjplayer.CircleElement;
 
 ///
@@ -12,6 +13,7 @@ class ProgramSet {
  public:
   ///
   alias Programs = Tuple!(
+      ActorProgram,
       BackgroundProgram,
       CircleElementProgram
     );