EEVEE: Color Ramp Ease Optimisation

This patch provides an optimisation for Ease (Smoothstep) setting in the color ramp node.
This optimisation exists already for Constant and Linear modes.

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D6880

1 files changed, 9 insertions, 0 deletions

diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_color_ramp.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_color_ramp.glsl
index 9fe45f91f45..17240da4050 100644
--- a/source/blender/gpu/shaders/material/gpu_shader_material_color_ramp.glsl
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_color_ramp.glsl
@@ -13,6 +13,15 @@ void valtorgb_opti_linear(
   outalpha = outcol.a;
 }
 
+void valtorgb_opti_ease(
+    float fac, vec2 mulbias, vec4 color1, vec4 color2, out vec4 outcol, out float outalpha)
+{
+  fac = clamp(fac * mulbias.x + mulbias.y, 0.0, 1.0);
+  fac = fac * fac * (3.0 - 2.0 * fac);
+  outcol = mix(color1, color2, fac);
+  outalpha = outcol.a;
+}
+
 void valtorgb(float fac, sampler1DArray colormap, float layer, out vec4 outcol, out float outalpha)
 {
   outcol = texture(colormap, vec2(fac, layer));