1 files changed, 111 insertions, 0 deletions
diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_fractal_noise.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_fractal_noise.glsl
new file mode 100644
index 00000000000..701b07b4aae
--- /dev/null
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_fractal_noise.glsl
@@ -0,0 +1,111 @@
+/* The fractal_noise functions are all exactly the same except for the input type. */
+float fractal_noise(float p, float octaves)
+{
+  float fscale = 1.0;
+  float amp = 1.0;
+  float sum = 0.0;
+  octaves = clamp(octaves, 0.0, 16.0);
+  int n = int(octaves);
+  for (int i = 0; i <= n; i++) {
+    float t = noise(fscale * p);
+    sum += t * amp;
+    amp *= 0.5;
+    fscale *= 2.0;
+  }
+  float rmd = octaves - floor(octaves);
+  if (rmd != 0.0) {
+    float t = noise(fscale * p);
+    float sum2 = sum + t * amp;
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    sum2 *= (float(1 << (n + 1)) / float((1 << (n + 2)) - 1));
+    return (1.0 - rmd) * sum + rmd * sum2;
+  }
+  else {
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    return sum;
+  }
+}
+
+/* The fractal_noise functions are all exactly the same except for the input type. */
+float fractal_noise(vec2 p, float octaves)
+{
+  float fscale = 1.0;
+  float amp = 1.0;
+  float sum = 0.0;
+  octaves = clamp(octaves, 0.0, 16.0);
+  int n = int(octaves);
+  for (int i = 0; i <= n; i++) {
+    float t = noise(fscale * p);
+    sum += t * amp;
+    amp *= 0.5;
+    fscale *= 2.0;
+  }
+  float rmd = octaves - floor(octaves);
+  if (rmd != 0.0) {
+    float t = noise(fscale * p);
+    float sum2 = sum + t * amp;
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    sum2 *= (float(1 << (n + 1)) / float((1 << (n + 2)) - 1));
+    return (1.0 - rmd) * sum + rmd * sum2;
+  }
+  else {
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    return sum;
+  }
+}
+
+/* The fractal_noise functions are all exactly the same except for the input type. */
+float fractal_noise(vec3 p, float octaves)
+{
+  float fscale = 1.0;
+  float amp = 1.0;
+  float sum = 0.0;
+  octaves = clamp(octaves, 0.0, 16.0);
+  int n = int(octaves);
+  for (int i = 0; i <= n; i++) {
+    float t = noise(fscale * p);
+    sum += t * amp;
+    amp *= 0.5;
+    fscale *= 2.0;
+  }
+  float rmd = octaves - floor(octaves);
+  if (rmd != 0.0) {
+    float t = noise(fscale * p);
+    float sum2 = sum + t * amp;
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    sum2 *= (float(1 << (n + 1)) / float((1 << (n + 2)) - 1));
+    return (1.0 - rmd) * sum + rmd * sum2;
+  }
+  else {
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    return sum;
+  }
+}
+
+/* The fractal_noise functions are all exactly the same except for the input type. */
+float fractal_noise(vec4 p, float octaves)
+{
+  float fscale = 1.0;
+  float amp = 1.0;
+  float sum = 0.0;
+  octaves = clamp(octaves, 0.0, 16.0);
+  int n = int(octaves);
+  for (int i = 0; i <= n; i++) {
+    float t = noise(fscale * p);
+    sum += t * amp;
+    amp *= 0.5;
+    fscale *= 2.0;
+  }
+  float rmd = octaves - floor(octaves);
+  if (rmd != 0.0) {
+    float t = noise(fscale * p);
+    float sum2 = sum + t * amp;
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    sum2 *= (float(1 << (n + 1)) / float((1 << (n + 2)) - 1));
+    return (1.0 - rmd) * sum + rmd * sum2;
+  }
+  else {
+    sum *= (float(1 << n) / float((1 << (n + 1)) - 1));
+    return sum;
+  }
+}