From be70827e6f62763d524f00652f61da6fc86e2714 Mon Sep 17 00:00:00 2001
From: Charlie Jolly <charlie>
Date: Thu, 30 Sep 2021 19:05:08 +0100
Subject: Nodes: Add Float Curve for GN and Shader nodes.

Replacement for float curve in legacy Attribute Curve Map node.

Float Curve defaults to [0.0-1.0] range.

Reviewed By: JacquesLucke, brecht

Differential Revision: https://developer.blender.org/D12683
---
 .../material/gpu_shader_material_float_curve.glsl  | 33 ++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 source/blender/gpu/shaders/material/gpu_shader_material_float_curve.glsl

(limited to 'source/blender/gpu/shaders/material')

diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_float_curve.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_float_curve.glsl
new file mode 100644
index 00000000000..514409f7fdf
--- /dev/null
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_float_curve.glsl
@@ -0,0 +1,33 @@
+/* ext is vec4(in_x, in_dy, out_x, out_dy). */
+float curve_float_extrapolate(float x, float y, vec4 ext)
+{
+  if (x < 0.0) {
+    return y + x * ext.y;
+  }
+  else if (x > 1.0) {
+    return y + (x - 1.0) * ext.w;
+  }
+  else {
+    return y;
+  }
+}
+
+#define RANGE_RESCALE(x, min, range) ((x - min) * range)
+
+void curve_float(float fac,
+                 float vec,
+                 sampler1DArray curvemap,
+                 float layer,
+                 float range,
+                 vec4 ext,
+                 out float outvec)
+{
+  float xyz_min = ext.x;
+  vec = RANGE_RESCALE(vec, xyz_min, range);
+
+  outvec = texture(curvemap, vec2(vec, layer)).x;
+
+  outvec = curve_float_extrapolate(vec, outvec, ext);
+
+  outvec = mix(vec, outvec, fac);
+}
-- 
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