From 325208d460a737cbcf3b041c4e925aa678d9cac5 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Thu, 22 Sep 2022 16:07:58 -0300
Subject: [PATCH] feat: implement better Colour Emulation

---
 src/platform.zig         | 11 ++++++-----
 src/shader/pixelbuf.frag | 24 ++++++++++++++++++------
 src/shader/pixelbuf.vert | 16 ++++++++--------
 3 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/src/platform.zig b/src/platform.zig
index f9b7d4d..3d3328a 100644
--- a/src/platform.zig
+++ b/src/platform.zig
@@ -25,10 +25,10 @@ pub const Gui = struct {
     // zig fmt: off
     const vertices: [32]f32 = [_]f32{
         // Positions        // Colours      // Texture Coords
-         1.0,  -1.0, 0.0,    1.0, 0.0, 0.0,  1.0, 1.0, // Top Right
-         1.0, 1.0, 0.0,    0.0, 1.0, 0.0,  1.0, 0.0, // Bottom Right
-        -1.0, 1.0, 0.0,    0.0, 0.0, 1.0,  0.0, 0.0, // Bottom Left
-        -1.0,  -1.0, 0.0,    1.0, 1.0, 0.0,  0.0, 1.0, // Top Left
+         1.0, -1.0, 0.0,    1.0, 0.0, 0.0,  1.0, 1.0, // Top Right
+         1.0,  1.0, 0.0,    0.0, 1.0, 0.0,  1.0, 0.0, // Bottom Right
+        -1.0,  1.0, 0.0,    0.0, 0.0, 1.0,  0.0, 0.0, // Bottom Left
+        -1.0, -1.0, 0.0,    1.0, 1.0, 0.0,  0.0, 1.0, // Top Left
     };
 
     const indices: [6]u32 = [_]u32{
@@ -236,7 +236,8 @@ pub const Gui = struct {
 
     pub fn deinit(self: *Self) void {
         self.audio.deinit();
-
+        // TODO: Buffer deletions
+        gl.deleteProgram(self.program_id);
         SDL.SDL_GL_DeleteContext(self.ctx);
         SDL.SDL_DestroyWindow(self.window);
         SDL.SDL_Quit();
diff --git a/src/shader/pixelbuf.frag b/src/shader/pixelbuf.frag
index f867bde..c45efae 100644
--- a/src/shader/pixelbuf.frag
+++ b/src/shader/pixelbuf.frag
@@ -1,13 +1,25 @@
 #version 330 core
-out vec4 FragColor;
+out vec4 frag_color;
 
-in vec3 ourColor;
-in vec2 TexCoord;
+in vec3 color;
+in vec2 uv;
 
-// texture sampler
-uniform sampler2D texture1;
+uniform sampler2D screen;
 
 void main() {
-	FragColor = texture(texture1, TexCoord);
+	// https://near.sh/video/color-emulation
+	// Thanks to Talarubi + Near for the Colour Correction
+	// Thanks to fleur + mattrb for the Shader Impl
+
+	vec4 color = texture(screen, uv);
+	color.rgb = pow(color.rgb, vec3(4.0)); // LCD Gamma
+  
+	frag_color = vec4(
+		pow(vec3(
+		  	  0 * color.b +  50 * color.g + 255 * color.r,
+	     	 30 * color.b + 230 * color.g +  10 * color.r,
+			220 * color.b +  10 * color.g +  50 * color.r
+		) / 255, vec3(1.0 / 2.2)), // Out Gamma
+	1.0); 
 }
 
diff --git a/src/shader/pixelbuf.vert b/src/shader/pixelbuf.vert
index 0738b36..43ef32e 100644
--- a/src/shader/pixelbuf.vert
+++ b/src/shader/pixelbuf.vert
@@ -1,13 +1,13 @@
 #version 330 core
-layout (location = 0) in vec3 aPos;
-layout (location = 1) in vec3 aColor;
-layout (location = 2) in vec2 aTexCoord;
+layout (location = 0) in vec3 pos;
+layout (location = 1) in vec3 in_color;
+layout (location = 2) in vec2 in_uv;
 
-out vec3 ourColor;
-out vec2 TexCoord;
+out vec3 color;
+out vec2 uv;
 
 void main() {
-	gl_Position = vec4(aPos, 1.0);
-	ourColor = aColor;
-	TexCoord = aTexCoord;
+	color = in_color;
+	uv = in_uv;
+	gl_Position = vec4(pos, 1.0);
 }
\ No newline at end of file