From 054950def946ed7638c2d9c18ef850cbba94d9d7 Mon Sep 17 00:00:00 2001
From: Bartosz Moniewski <monio>
Date: Thu, 26 Mar 2020 14:43:53 +0100
Subject: Shading: add Roughness input to Noise and Wave texture nodes

Currently in fractal_noise functions, each subsequent octave doubles the
frequency and reduces the amplitude by half. This patch introduces Roughness
input to Noise and Wave nodes. This multiplier determines how quickly the
amplitudes of the subsequent octaves decrease.

Value of 0.5 will be the default, generating identical noise we had before.
Values above 0.5 will increase influence of each octave resulting in more
"rough" noise, most interesting pattern changes happen there. Values below
0.5 will result in more "smooth" noise.

Differential Revision: https://developer.blender.org/D7065
---
 .../material/gpu_shader_material_tex_noise.glsl    | 64 +++++++++++++++-------
 1 file changed, 44 insertions(+), 20 deletions(-)

(limited to 'source/blender/gpu/shaders/material/gpu_shader_material_tex_noise.glsl')

diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_tex_noise.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_tex_noise.glsl
index 6aeb23b1f99..d8d9ecdf287 100644
--- a/source/blender/gpu/shaders/material/gpu_shader_material_tex_noise.glsl
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_tex_noise.glsl
@@ -32,23 +32,35 @@ vec4 random_vec4_offset(float seed)
               100.0 + hash_vec2_to_float(vec2(seed, 3.0)) * 100.0);
 }
 
-void node_noise_texture_1d(
-    vec3 co, float w, float scale, float detail, float distortion, out float value, out vec4 color)
+void node_noise_texture_1d(vec3 co,
+                           float w,
+                           float scale,
+                           float detail,
+                           float roughness,
+                           float distortion,
+                           out float value,
+                           out vec4 color)
 {
   float p = w * scale;
   if (distortion != 0.0) {
     p += snoise(p + random_float_offset(0.0)) * distortion;
   }
 
-  value = fractal_noise(p, detail);
+  value = fractal_noise(p, detail, roughness);
   color = vec4(value,
-               fractal_noise(p + random_float_offset(1.0), detail),
-               fractal_noise(p + random_float_offset(2.0), detail),
+               fractal_noise(p + random_float_offset(1.0), detail, roughness),
+               fractal_noise(p + random_float_offset(2.0), detail, roughness),
                1.0);
 }
 
-void node_noise_texture_2d(
-    vec3 co, float w, float scale, float detail, float distortion, out float value, out vec4 color)
+void node_noise_texture_2d(vec3 co,
+                           float w,
+                           float scale,
+                           float detail,
+                           float roughness,
+                           float distortion,
+                           out float value,
+                           out vec4 color)
 {
   vec2 p = co.xy * scale;
   if (distortion != 0.0) {
@@ -56,15 +68,21 @@ void node_noise_texture_2d(
               snoise(p + random_vec2_offset(1.0)) * distortion);
   }
 
-  value = fractal_noise(p, detail);
+  value = fractal_noise(p, detail, roughness);
   color = vec4(value,
-               fractal_noise(p + random_vec2_offset(2.0), detail),
-               fractal_noise(p + random_vec2_offset(3.0), detail),
+               fractal_noise(p + random_vec2_offset(2.0), detail, roughness),
+               fractal_noise(p + random_vec2_offset(3.0), detail, roughness),
                1.0);
 }
 
-void node_noise_texture_3d(
-    vec3 co, float w, float scale, float detail, float distortion, out float value, out vec4 color)
+void node_noise_texture_3d(vec3 co,
+                           float w,
+                           float scale,
+                           float detail,
+                           float roughness,
+                           float distortion,
+                           out float value,
+                           out vec4 color)
 {
   vec3 p = co * scale;
   if (distortion != 0.0) {
@@ -73,15 +91,21 @@ void node_noise_texture_3d(
               snoise(p + random_vec3_offset(2.0)) * distortion);
   }
 
-  value = fractal_noise(p, detail);
+  value = fractal_noise(p, detail, roughness);
   color = vec4(value,
-               fractal_noise(p + random_vec3_offset(3.0), detail),
-               fractal_noise(p + random_vec3_offset(4.0), detail),
+               fractal_noise(p + random_vec3_offset(3.0), detail, roughness),
+               fractal_noise(p + random_vec3_offset(4.0), detail, roughness),
                1.0);
 }
 
-void node_noise_texture_4d(
-    vec3 co, float w, float scale, float detail, float distortion, out float value, out vec4 color)
+void node_noise_texture_4d(vec3 co,
+                           float w,
+                           float scale,
+                           float detail,
+                           float roughness,
+                           float distortion,
+                           out float value,
+                           out vec4 color)
 {
   vec4 p = vec4(co, w) * scale;
   if (distortion != 0.0) {
@@ -91,9 +115,9 @@ void node_noise_texture_4d(
               snoise(p + random_vec4_offset(3.0)) * distortion);
   }
 
-  value = fractal_noise(p, detail);
+  value = fractal_noise(p, detail, roughness);
   color = vec4(value,
-               fractal_noise(p + random_vec4_offset(4.0), detail),
-               fractal_noise(p + random_vec4_offset(5.0), detail),
+               fractal_noise(p + random_vec4_offset(4.0), detail, roughness),
+               fractal_noise(p + random_vec4_offset(5.0), detail, roughness),
                1.0);
 }
-- 
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