From 0f34a7427b9f762039c25057a891481030b1bead Mon Sep 17 00:00:00 2001
From: RokkumanX <50436544+RokkumanX@users.noreply.github.com>
Date: Mon, 28 Sep 2020 09:31:33 +0200
Subject: [PATCH] Add PSP color shader

This adds the PSP color shader ported from RetroArch courtesy from @jdgleaver (https://forums.ppsspp.org/showthread.php?tid=6594&pid=130635#pid130635) to PPSSPP

Also updated with up to date changes found here (https://github.com/libretro/glsl-shaders/blob/master/handheld/shaders/color/psp-color.glsl)
---
 assets/shaders/psp_color.fsh | 58 ++++++++++++++++++++++++++++++++++++
 assets/shaders/psp_color.ini |  6 ++++
 assets/shaders/psp_color.vsh | 23 ++++++++++++++
 3 files changed, 87 insertions(+)
 create mode 100644 assets/shaders/psp_color.fsh
 create mode 100644 assets/shaders/psp_color.ini
 create mode 100644 assets/shaders/psp_color.vsh

diff --git a/assets/shaders/psp_color.fsh b/assets/shaders/psp_color.fsh
new file mode 100644
index 0000000000..aad99df883
--- /dev/null
+++ b/assets/shaders/psp_color.fsh
@@ -0,0 +1,58 @@
+/*
+	psp_color vertex shader
+	
+	Original code written by hunterk, modified by Pokefan531 and
+	released into the public domain
+	
+	'Ported' (i.e. copy/paste) to PPSSPP format by jdgleaver
+	
+	This program is free software; you can redistribute it and/or modify it
+	under the terms of the GNU General Public License as published by the Free
+	Software Foundation; either version 2 of the License, or (at your option)
+	any later version.
+	
+	Notes: This shader replicates the LCD dynamics of the PSP 1000 and PSP 2000
+*/
+
+//================
+#ifdef GL_ES
+precision mediump float;
+precision mediump int;
+// For android, use this instead...
+//precision highp float;
+//precision highp int;
+//
+#endif
+
+//================
+#define target_gamma 2.21
+#define display_gamma 2.2
+#define r 0.98
+#define g 0.795
+#define b 0.98
+#define rg 0.04
+#define rb 0.01
+#define gr 0.20
+#define gb 0.01
+#define br -0.18
+#define bg 0.165
+
+//================
+uniform sampler2D sampler0;
+varying vec2 v_texcoord0;
+
+//================
+void main()
+{
+	// Apply colour correction
+	vec3 screen = pow(texture2D(sampler0, v_texcoord0.xy).rgb, vec3(target_gamma));
+	screen = clamp(screen, 0.0, 1.0);
+	screen = pow(
+		mat3(r,  rg, rb,
+			  gr, g,  gb,
+			  br, bg, b) * screen,
+		vec3(1.0 / display_gamma)
+	);
+	
+	gl_FragColor = vec4(screen, 1.0);
+}
diff --git a/assets/shaders/psp_color.ini b/assets/shaders/psp_color.ini
new file mode 100644
index 0000000000..73cae04bb2
--- /dev/null
+++ b/assets/shaders/psp_color.ini
@@ -0,0 +1,6 @@
+[PSP Color]
+Name=PSP Color
+Author=hunterk, Pokefan531 (ported by jdgleaver)
+Fragment=psp_color.fsh
+Vertex=psp_color.vsh
+OutputResolution=True
diff --git a/assets/shaders/psp_color.vsh b/assets/shaders/psp_color.vsh
new file mode 100644
index 0000000000..0353e17dae
--- /dev/null
+++ b/assets/shaders/psp_color.vsh
@@ -0,0 +1,23 @@
+/*
+	psp_color vertex shader
+	
+	Original code written by hunterk, modified by Pokefan531 and
+	released into the public domain
+	
+	'Ported' (i.e. copy/paste) to PPSSPP format by jdgleaver
+	
+	This program is free software; you can redistribute it and/or modify it
+	under the terms of the GNU General Public License as published by the Free
+	Software Foundation; either version 2 of the License, or (at your option)
+	any later version.
+*/
+
+attribute vec4 a_position;
+attribute vec2 a_texcoord0;
+varying vec2 v_texcoord0;
+
+void main()
+{
+	v_texcoord0 = a_texcoord0; // + 0.000001; // HLSL precision workaround (is this needed???)
+	gl_Position = a_position;
+}