From daf4721fa94880e6e12eb725a9f983053061f720 Mon Sep 17 00:00:00 2001
From: samuncle <samuncle06@gmail.com>
Date: Sat, 7 Apr 2018 04:11:11 +0200
Subject: [PATCH] Add a mitigation for tilling textures. Very usefull for
 terrains, etc

---
 data/shaders/sp_tilling_mitigation.frag     | 21 +-----
 data/shaders/utils/sp_texture_sampling.frag | 78 +++++++++++++++++++++
 2 files changed, 81 insertions(+), 18 deletions(-)

diff --git a/data/shaders/sp_tilling_mitigation.frag b/data/shaders/sp_tilling_mitigation.frag
index 5186ef89f..8a2f46d10 100644
--- a/data/shaders/sp_tilling_mitigation.frag
+++ b/data/shaders/sp_tilling_mitigation.frag
@@ -15,22 +15,7 @@ layout(location = 1) out vec4 o_normal_color;
 
 void main()
 {
-    vec4 col = sampleTextureLayer0(uv);
-    vec4 col2 = sampleTextureLayer0(uv * 2.0);
-    vec4 col3 = sampleTextureLayer0(uv * 4.0);
-
-    // From Low to medium
-    float factor = camdist * 0.01;
-    factor = pow(factor - 0.1, 1.4);
-    factor = clamp(factor, 0.0, 1.0);
-    col = mix(col2, col, factor);
-    
-    // From medium to high
-    factor = camdist * 0.01;
-    factor = pow(factor - 0.1, 0.4);
-    factor = clamp(factor, 0.0, 1.0);
-
-    col = mix(col3, col, factor);
+    vec4 col = multi_sampleTextureLayer0(uv, camdist);
 
     if (hue_change > 0.0)
     {
@@ -52,8 +37,8 @@ void main()
     vec3 final_color = col.xyz * color.xyz;
 
 #if defined(Advanced_Lighting_Enabled)
-    vec4 layer_2 = sampleTextureLayer2(uv);
-    vec4 layer_3 = sampleTextureLayer3(uv);
+    vec4 layer_2 = multi_sampleTextureLayer2(uv, camdist);
+    vec4 layer_3 = multi_sampleTextureLayer3(uv, camdist);
     o_diffuse_color = vec4(final_color, layer_2.z);
 
     vec3 tangent_space_normal = 2.0 * layer_3.xyz - 1.0;
diff --git a/data/shaders/utils/sp_texture_sampling.frag b/data/shaders/utils/sp_texture_sampling.frag
index 1dfbab0df..3ff725185 100644
--- a/data/shaders/utils/sp_texture_sampling.frag
+++ b/data/shaders/utils/sp_texture_sampling.frag
@@ -6,11 +6,43 @@ uniform sampler2D tex_layer_3;
 uniform sampler2D tex_layer_4;
 uniform sampler2D tex_layer_5;
 
+#define HIGH_SAMPLING   4.0
+#define MEDIUM_SAMPLING 2.0
+#define LOW_SAMPLING    1.0
+
 vec4 sampleTextureLayer0(vec2 uv)
 {
     return texture(tex_layer_0, uv);
 }
 
+vec4 multi_sampleTextureLayer0(vec2 uv, float distance)
+{
+
+    vec4 l_col = sampleTextureLayer0(uv * LOW_SAMPLING);
+    vec4 m_col = sampleTextureLayer0(uv * MEDIUM_SAMPLING);
+    vec4 h_col = sampleTextureLayer0(uv * HIGH_SAMPLING);
+
+    /* debug
+    l_col = vec4(1.0, 0.0, 0.0, 1.0);
+    m_col = vec4(0.0, 1.0, 0.0, 1.0);
+    h_col = vec4(0.0, 0.0, 1.0, 1.0);*/
+
+    // From Low to medium
+    float factor = distance * 0.02;
+    factor = pow(factor, 2.5);
+    factor = clamp(factor, 0.0, 1.0);
+    vec4 f_col = mix(m_col, l_col, factor);
+    
+    // From medium to high
+    factor = distance * 0.1;
+    factor = pow(factor, 2.5);
+    factor = clamp(factor, 0.0, 1.0);
+
+    f_col = mix(h_col, f_col, factor);
+
+    return f_col;
+}
+
 vec4 sampleTextureLayer1(vec2 uv)
 {
     return texture(tex_layer_1, uv);
@@ -21,11 +53,57 @@ vec4 sampleTextureLayer2(vec2 uv)
     return texture(tex_layer_2, uv);
 }
 
+vec4 multi_sampleTextureLayer2(vec2 uv, float distance)
+{
+
+    vec4 l_col = sampleTextureLayer2(uv * LOW_SAMPLING);
+    vec4 m_col = sampleTextureLayer2(uv * MEDIUM_SAMPLING);
+    vec4 h_col = sampleTextureLayer2(uv * HIGH_SAMPLING);
+
+    // From Low to medium
+    float factor = distance * 0.02;
+    factor = pow(factor, 2.5);
+    factor = clamp(factor, 0.0, 1.0);
+    vec4 f_col = mix(m_col, l_col, factor);
+    
+    // From medium to high
+    factor = distance * 0.1;
+    factor = pow(factor, 2.5);
+    factor = clamp(factor, 0.0, 1.0);
+
+    f_col = mix(h_col, f_col, factor);
+
+    return f_col;
+}
+
 vec4 sampleTextureLayer3(vec2 uv)
 {
     return texture(tex_layer_3, uv);
 }
 
+vec4 multi_sampleTextureLayer3(vec2 uv, float distance)
+{
+
+    vec4 l_col = sampleTextureLayer3(uv * LOW_SAMPLING);
+    vec4 m_col = sampleTextureLayer3(uv * MEDIUM_SAMPLING);
+    vec4 h_col = sampleTextureLayer3(uv * HIGH_SAMPLING);
+
+    // From Low to medium
+    float factor = distance * 0.02;
+    factor = pow(factor, 2.5);
+    factor = clamp(factor, 0.0, 1.0);
+    vec4 f_col = mix(m_col, l_col, factor);
+    
+    // From medium to high
+    factor = distance * 0.1;
+    factor = pow(factor, 2.5);
+    factor = clamp(factor, 0.0, 1.0);
+
+    f_col = mix(h_col, f_col, factor);
+
+    return f_col;
+}
+
 vec4 sampleTextureLayer4(vec2 uv)
 {
     return texture(tex_layer_4, uv);