From 93ac2c1e2a8e1b29390455cb47bc231b9954dd0b Mon Sep 17 00:00:00 2001
From: falsycat <me@falsy.cat>
Date: Wed, 9 Oct 2019 00:00:00 +0000
Subject: [PATCH] [add] Added PostEffect.

---
 sjplayer/src/sjplayer/PostEffect.d | 148 +++++++++++++++++++++++++++++
 sjplayer/src/sjplayer/ProgramSet.d |   6 +-
 2 files changed, 152 insertions(+), 2 deletions(-)
 create mode 100644 sjplayer/src/sjplayer/PostEffect.d

diff --git a/sjplayer/src/sjplayer/PostEffect.d b/sjplayer/src/sjplayer/PostEffect.d
new file mode 100644
index 0000000..3099179
--- /dev/null
+++ b/sjplayer/src/sjplayer/PostEffect.d
@@ -0,0 +1,148 @@
+/// License: MIT
+module sjplayer.PostEffect;
+
+import gl4d;
+
+///
+class PostEffect {
+ public:
+  ///
+  this(PostEffectProgram program, vec2i sz) {
+    size_    = sz;
+    program_ = program;
+    fb_      = Framebuffer.Create();
+    tex_     = TextureRect.Create();
+    sampler_ = Sampler.Create();
+
+    TextureRectAllocator allocator;
+    with (allocator) {
+      internalFormat = GL_RGB;
+      size           = sz;
+      format         = GL_RED;
+      type           = GL_UNSIGNED_BYTE;
+      data           = null;
+      Allocate(tex_);
+    }
+
+    SamplerConfigurer configurer;
+    with (configurer) {
+      filterMin = GL_NEAREST;
+      filterMag = GL_NEAREST;
+      Configure(sampler_);
+    }
+
+    fb_.Bind();
+    fb_.attachment!(GL_COLOR_ATTACHMENT0, 0, GL_TEXTURE_RECTANGLE) = tex_;
+    fb_.attachmentOrder = [GL_COLOR_ATTACHMENT0];
+    fb_.Validate();
+    fb_.Unbind();
+  }
+
+  ///
+  void BindFramebuffer() {
+    fb_.Bind();
+  }
+  ///
+  void UnbindFramebuffer() {
+    fb_.Unbind();
+  }
+  ///
+  void DrawFramebuffer() {
+    program_.Draw(tex_, sampler_, size_);
+  }
+
+ private:
+  const vec2i size_;
+
+  PostEffectProgram program_;
+
+  FramebufferRef fb_;
+
+  TextureRectRef tex_;
+
+  SamplerRef sampler_;
+}
+
+///
+class PostEffectProgram {
+ 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+vec2(1, 1)) / 2;
+      gl_Position = vec4(vert, 0, 1);
+    }
+  };
+  ///
+  enum FragmentShaderSrc = ShaderHeader ~ q{
+    layout(location = 0) uniform sampler2DRect fb;
+    layout(location = 1) uniform ivec2         fb_size;
+
+    in vec2  uv_;
+
+    out vec4 pixel_;
+
+    void main() {
+      pixel_ = texture(fb, fb_size * uv_);
+    }
+  };
+
+  ///
+  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(ref TextureRectRef fb, ref SamplerRef sampler, vec2i size) {
+    program_.Use();
+
+    fb.BindToUnit(GL_TEXTURE0);
+    sampler.Bind(0);
+    program_.uniform!0 = 0;
+    program_.uniform!1 = size;
+
+    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 7225c60..0f7a92c 100644
--- a/sjplayer/src/sjplayer/ProgramSet.d
+++ b/sjplayer/src/sjplayer/ProgramSet.d
@@ -6,7 +6,8 @@ import std.meta,
 
 import sjplayer.Actor,
        sjplayer.Background,
-       sjplayer.CircleElement;
+       sjplayer.CircleElement,
+       sjplayer.PostEffect;
 
 ///
 class ProgramSet {
@@ -15,7 +16,8 @@ class ProgramSet {
   alias Programs = Tuple!(
       ActorProgram,
       BackgroundProgram,
-      CircleElementProgram
+      CircleElementProgram,
+      PostEffectProgram,
     );
 
   ///