From 9d562a454b570d7f83c5483e98003901417bd030 Mon Sep 17 00:00:00 2001
From: KrossX <krossx@yahoo.com>
Date: Tue, 2 Oct 2018 21:42:02 +0200
Subject: [PATCH] GSdx: Limit Wrap negative UV when PS_FST is 0 only.

---
 plugins/GSdx/res/glsl/tfx_fs.glsl | 18 ++++++++++++++----
 plugins/GSdx/res/tfx.fx           | 17 ++++++++++++++---
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/plugins/GSdx/res/glsl/tfx_fs.glsl b/plugins/GSdx/res/glsl/tfx_fs.glsl
index 8c475f162d..3fec14f638 100644
--- a/plugins/GSdx/res/glsl/tfx_fs.glsl
+++ b/plugins/GSdx/res/glsl/tfx_fs.glsl
@@ -127,7 +127,12 @@ vec4 clamp_wrap_uv(vec4 uv)
 #if PS_WMS == 2
     uv_out = clamp(uv, MinMax.xyxy, MinMax.zwzw);
 #elif PS_WMS == 3
-    uv_out = vec4((uvec4(fract(uv) * WH.xyxy) & ivec4(MskFix.xyxy)) | ivec4(MskFix.zwzw)) / WH.xyxy;
+    #if PS_FST == 0
+    // wrap negative uv coords to avoid an off by one error that shifted
+    // textures. Fixes Xenosaga's hair issue.
+    uv = fract(uv);
+    #endif
+    uv_out = vec4((uvec4(uv * WH.xyxy) & ivec4(MskFix.xyxy)) | ivec4(MskFix.zwzw)) / WH.xyxy;
 #endif
 
 #else // PS_WMS != PS_WMT
@@ -136,7 +141,10 @@ vec4 clamp_wrap_uv(vec4 uv)
     uv_out.xz = clamp(uv.xz, MinMax.xx, MinMax.zz);
 
 #elif PS_WMS == 3
-    uv_out.xz = vec2((uvec2(fract(uv.xz) * WH.xx) & ivec2(MskFix.xx)) | ivec2(MskFix.zz)) / WH.xx;
+    #if PS_FST == 0
+    uv.xz = fract(uv.xz);
+    #endif
+    uv_out.xz = vec2((uvec2(uv.xz * WH.xx) & ivec2(MskFix.xx)) | ivec2(MskFix.zz)) / WH.xx;
 
 #endif
 
@@ -144,8 +152,10 @@ vec4 clamp_wrap_uv(vec4 uv)
     uv_out.yw = clamp(uv.yw, MinMax.yy, MinMax.ww);
 
 #elif PS_WMT == 3
-
-    uv_out.yw = vec2((uvec2(fract(uv.yw) * WH.yy) & ivec2(MskFix.yy)) | ivec2(MskFix.ww)) / WH.yy;
+    #if PS_FST == 0
+    uv.yw = fract(uv.yw);
+    #endif
+    uv_out.yw = vec2((uvec2(uv.yw * WH.yy) & ivec2(MskFix.yy)) | ivec2(MskFix.ww)) / WH.yy;
 #endif
 
 #endif
diff --git a/plugins/GSdx/res/tfx.fx b/plugins/GSdx/res/tfx.fx
index d54417dac8..fb61020386 100644
--- a/plugins/GSdx/res/tfx.fx
+++ b/plugins/GSdx/res/tfx.fx
@@ -254,7 +254,12 @@ float4 clamp_wrap_uv(float4 uv)
 		else if(PS_WMS == 3)
 		{
 			#if SHADER_MODEL >= 0x400
-			uv = (float4)(((uint4)(frac(uv) * WH.xyxy) & MskFix.xyxy) | MskFix.zwzw) / WH.xyxy;
+			#if PS_FST == 0
+			// wrap negative uv coords to avoid an off by one error that shifted
+			// textures. Fixes Xenosaga's hair issue.
+			uv = frac(uv);
+			#endif
+			uv = (float4)(((uint4)(uv * WH.xyxy) & MskFix.xyxy) | MskFix.zwzw) / WH.xyxy;
 			#elif SHADER_MODEL <= 0x300
 			uv.x = tex1D(UMSKFIX, uv.x);
 			uv.y = tex1D(VMSKFIX, uv.y);
@@ -283,7 +288,10 @@ float4 clamp_wrap_uv(float4 uv)
 		else if(PS_WMS == 3)
 		{
 			#if SHADER_MODEL >= 0x400
-			uv.xz = (float2)(((uint2)(frac(uv.xz) * WH.xx) & MskFix.xx) | MskFix.zz) / WH.xx;
+			#if PS_FST == 0
+			uv.xz = frac(uv.xz);
+			#endif
+			uv.xz = (float2)(((uint2)(uv.xz * WH.xx) & MskFix.xx) | MskFix.zz) / WH.xx;
 			#elif SHADER_MODEL <= 0x300
 			uv.x = tex1D(UMSKFIX, uv.x);
 			uv.z = tex1D(UMSKFIX, uv.z);
@@ -307,7 +315,10 @@ float4 clamp_wrap_uv(float4 uv)
 		else if(PS_WMT == 3)
 		{
 			#if SHADER_MODEL >= 0x400
-			uv.yw = (float2)(((uint2)(frac(uv.yw) * WH.yy) & MskFix.yy) | MskFix.ww) / WH.yy;
+			#if PS_FST == 0
+			uv.yw = frac(uv.yw);
+			#endif
+			uv.yw = (float2)(((uint2)(uv.yw * WH.yy) & MskFix.yy) | MskFix.ww) / WH.yy;
 			#elif SHADER_MODEL <= 0x300
 			uv.y = tex1D(VMSKFIX, uv.y);
 			uv.w = tex1D(VMSKFIX, uv.w);