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

3 files changed, 70 insertions, 1 deletions

diff --git a/intern/cycles/kernel/svm/svm.h b/intern/cycles/kernel/svm/svm.h
index 4aee1ef11b3..ad609b15f86 100644
--- a/intern/cycles/kernel/svm/svm.h
+++ b/intern/cycles/kernel/svm/svm.h
@@ -493,11 +493,13 @@ ccl_device void svm_eval_nodes(INTEGRATOR_STATE_CONST_ARGS,
       case NODE_IES:
         svm_node_ies(kg, sd, stack, node);
         break;
-
       case NODE_RGB_CURVES:
       case NODE_VECTOR_CURVES:
         offset = svm_node_curves(kg, sd, stack, node, offset);
         break;
+      case NODE_FLOAT_CURVE:
+        offset = svm_node_curve(kg, sd, stack, node, offset);
+        break;
       case NODE_TANGENT:
         svm_node_tangent(kg, sd, stack, node);
         break;
diff --git a/intern/cycles/kernel/svm/svm_ramp.h b/intern/cycles/kernel/svm/svm_ramp.h
index e92df3c093c..563e5bcb5e4 100644
--- a/intern/cycles/kernel/svm/svm_ramp.h
+++ b/intern/cycles/kernel/svm/svm_ramp.h
@@ -21,6 +21,48 @@ CCL_NAMESPACE_BEGIN
 
 /* NOTE: svm_ramp.h, svm_ramp_util.h and node_ramp_util.h must stay consistent */
 
+ccl_device_inline float fetch_float(const KernelGlobals *kg, int offset)
+{
+  uint4 node = kernel_tex_fetch(__svm_nodes, offset);
+  return __uint_as_float(node.x);
+}
+
+ccl_device_inline float float_ramp_lookup(const KernelGlobals *kg,
+                                          int offset,
+                                          float f,
+                                          bool interpolate,
+                                          bool extrapolate,
+                                          int table_size)
+{
+  if ((f < 0.0f || f > 1.0f) && extrapolate) {
+    float t0, dy;
+    if (f < 0.0f) {
+      t0 = fetch_float(kg, offset);
+      dy = t0 - fetch_float(kg, offset + 1);
+      f = -f;
+    }
+    else {
+      t0 = fetch_float(kg, offset + table_size - 1);
+      dy = t0 - fetch_float(kg, offset + table_size - 2);
+      f = f - 1.0f;
+    }
+    return t0 + dy * f * (table_size - 1);
+  }
+
+  f = saturate(f) * (table_size - 1);
+
+  /* clamp int as well in case of NaN */
+  int i = clamp(float_to_int(f), 0, table_size - 1);
+  float t = f - (float)i;
+
+  float a = fetch_float(kg, offset + i);
+
+  if (interpolate && t > 0.0f)
+    a = (1.0f - t) * a + t * fetch_float(kg, offset + i + 1);
+
+  return a;
+}
+
 ccl_device_inline float4 rgb_ramp_lookup(const KernelGlobals *kg,
                                          int offset,
                                          float f,
@@ -105,6 +147,30 @@ ccl_device_noinline int svm_node_curves(
   return offset;
 }
 
+ccl_device_noinline int svm_node_curve(
+    const KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, int offset)
+{
+  uint fac_offset, value_in_offset, out_offset;
+  svm_unpack_node_uchar3(node.y, &fac_offset, &value_in_offset, &out_offset);
+
+  uint table_size = read_node(kg, &offset).x;
+
+  float fac = stack_load_float(stack, fac_offset);
+  float in = stack_load_float(stack, value_in_offset);
+
+  const float min = __int_as_float(node.z), max = __int_as_float(node.w);
+  const float range = max - min;
+  const float relpos = (in - min) / range;
+
+  float v = float_ramp_lookup(kg, offset, relpos, true, true, table_size);
+
+  in = (1.0f - fac) * in + fac * v;
+  stack_store_float(stack, out_offset, in);
+
+  offset += table_size;
+  return offset;
+}
+
 CCL_NAMESPACE_END
 
 #endif /* __SVM_RAMP_H__ */
diff --git a/intern/cycles/kernel/svm/svm_types.h b/intern/cycles/kernel/svm/svm_types.h
index 313bc3235b9..59a0e33acbc 100644
--- a/intern/cycles/kernel/svm/svm_types.h
+++ b/intern/cycles/kernel/svm/svm_types.h
@@ -122,6 +122,7 @@ typedef enum ShaderNodeType {
   NODE_AOV_START,
   NODE_AOV_COLOR,
   NODE_AOV_VALUE,
+  NODE_FLOAT_CURVE,
   /* NOTE: for best OpenCL performance, item definition in the enum must
    * match the switch case order in svm.h. */
 } ShaderNodeType;