From 7ea0e906782a9ed8f4bdb89c87024b318f8a529c Mon Sep 17 00:00:00 2001
From: Gregory Hainaut <gregory.hainaut@gmail.com>
Date: Thu, 6 Oct 2016 20:15:50 +0200
Subject: [PATCH] gsdx mipmap:ogl: extend shader to support trilinear filtering

---
 plugins/GSdx/GSDeviceOGL.cpp      |  2 ++
 plugins/GSdx/GSDeviceOGL.h        |  4 +++-
 plugins/GSdx/res/glsl/tfx_fs.glsl | 19 +++++++++++++++++++
 plugins/GSdx/res/glsl_source.h    | 19 +++++++++++++++++++
 4 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/plugins/GSdx/GSDeviceOGL.cpp b/plugins/GSdx/GSDeviceOGL.cpp
index 3913747b4d..c7d4d91d6a 100644
--- a/plugins/GSdx/GSDeviceOGL.cpp
+++ b/plugins/GSdx/GSDeviceOGL.cpp
@@ -954,6 +954,8 @@ GLuint GSDeviceOGL::CompilePS(PSSelector sel)
 		+ format("#define PS_CLR1 %d\n", sel.clr1)
 		+ format("#define PS_FBA %d\n", sel.fba)
 		+ format("#define PS_LTF %d\n", sel.ltf)
+		+ format("#define PS_AUTOMATIC_LOD %d\n", sel.automatic_lod)
+		+ format("#define PS_MANUAL_LOD %d\n", sel.manual_lod)
 		+ format("#define PS_COLCLIP %d\n", sel.colclip)
 		+ format("#define PS_DATE %d\n", sel.date)
 		+ format("#define PS_TCOFFSETHACK %d\n", sel.tcoffsethack)
diff --git a/plugins/GSdx/GSDeviceOGL.h b/plugins/GSdx/GSDeviceOGL.h
index 60d5560916..522fb06490 100644
--- a/plugins/GSdx/GSDeviceOGL.h
+++ b/plugins/GSdx/GSDeviceOGL.h
@@ -293,8 +293,10 @@ public:
 				uint32 urban_chaos_hle:1;
 				uint32 tales_of_abyss_hle:1;
 				uint32 tex_is_fb:1; // Jak Shadows
+				uint32 automatic_lod:1;
+				uint32 manual_lod:1;
 
-				uint32 _free2:13;
+				uint32 _free2:11;
 			};
 
 			uint64 key;
diff --git a/plugins/GSdx/res/glsl/tfx_fs.glsl b/plugins/GSdx/res/glsl/tfx_fs.glsl
index 5eb59313c3..530b3d4f7b 100644
--- a/plugins/GSdx/res/glsl/tfx_fs.glsl
+++ b/plugins/GSdx/res/glsl/tfx_fs.glsl
@@ -78,7 +78,26 @@ vec4 sample_c(vec2 uv)
 #if PS_TEX_IS_FB == 1
     return texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0);
 #else
+
+#if PS_AUTOMATIC_LOD == 1
     return texture(TextureSampler, uv);
+#elif PS_MANUAL_LOD == 1
+    // FIXME add LOD: K - ( LOG2(Q) * (1 << L))
+    float K = MinMax.x;
+    float L = MinMax.y;
+    float bias = MinMax.z;
+    float max_lod = MinMax.w;
+
+    float gs_lod = K - log2(abs(PSin.t_float.w)) * L;
+    // FIXME max useful ?
+    //float lod = max(min(gs_lod, max_lod) - bias, 0.0f);
+    float lod = min(gs_lod, max_lod) - bias;
+
+    return textureLod(TextureSampler, uv, lod);
+#else
+    return textureLod(TextureSampler, uv, 0); // No lod
+#endif
+
 #endif
 }
 
diff --git a/plugins/GSdx/res/glsl_source.h b/plugins/GSdx/res/glsl_source.h
index b004cdf88e..b71f146f99 100644
--- a/plugins/GSdx/res/glsl_source.h
+++ b/plugins/GSdx/res/glsl_source.h
@@ -998,7 +998,26 @@ static const char* const tfx_fs_all_glsl =
 	"#if PS_TEX_IS_FB == 1\n"
 	"    return texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0);\n"
 	"#else\n"
+	"\n"
+	"#if PS_AUTOMATIC_LOD == 1\n"
 	"    return texture(TextureSampler, uv);\n"
+	"#elif PS_MANUAL_LOD == 1\n"
+	"    // FIXME add LOD: K - ( LOG2(Q) * (1 << L))\n"
+	"    float K = MinMax.x;\n"
+	"    float L = MinMax.y;\n"
+	"    float bias = MinMax.z;\n"
+	"    float max_lod = MinMax.w;\n"
+	"\n"
+	"    float gs_lod = K - log2(abs(PSin.t_float.w)) * L;\n"
+	"    // FIXME max useful ?\n"
+	"    //float lod = max(min(gs_lod, max_lod) - bias, 0.0f);\n"
+	"    float lod = min(gs_lod, max_lod) - bias;\n"
+	"\n"
+	"    return textureLod(TextureSampler, uv, lod);\n"
+	"#else\n"
+	"    return textureLod(TextureSampler, uv, 0); // No lod\n"
+	"#endif\n"
+	"\n"
 	"#endif\n"
 	"}\n"
 	"\n"