Node: Mix node

This patch is a response to T92588 and is implemented
as a Function/Shader node.

This node has support for Float, Vector and Color data types.

For Vector it supports uniform and non-uniform mixing.

For Color it now has the option to remove factor clamping.

It replaces the Mix RGB for Shader and Geometry node trees.

As discussed in T96219, this patch converts existing nodes
in .blend files. The old node is still available in the
Python API but hidden from the menus.

Reviewed By: HooglyBoogly, JacquesLucke, simonthommes, brecht

Maniphest Tasks: T92588

Differential Revision: https://developer.blender.org/D13749

4 files changed, 384 insertions, 2 deletions

diff --git a/intern/cycles/scene/constant_fold.cpp b/intern/cycles/scene/constant_fold.cpp
index 4bce5661f9b..1aa4515a087 100644
--- a/intern/cycles/scene/constant_fold.cpp
+++ b/intern/cycles/scene/constant_fold.cpp
@@ -291,6 +291,101 @@ void ConstantFolder::fold_mix(NodeMix type, bool clamp) const
   }
 }
 
+void ConstantFolder::fold_mix_color(NodeMix type, bool clamp_factor, bool clamp) const
+{
+  ShaderInput *fac_in = node->input("Factor");
+  ShaderInput *color1_in = node->input("A");
+  ShaderInput *color2_in = node->input("B");
+
+  float fac = clamp_factor ? saturatef(node->get_float(fac_in->socket_type)) :
+                             node->get_float(fac_in->socket_type);
+  bool fac_is_zero = !fac_in->link && fac == 0.0f;
+  bool fac_is_one = !fac_in->link && fac == 1.0f;
+
+  /* remove no-op node when factor is 0.0 */
+  if (fac_is_zero) {
+    /* note that some of the modes will clamp out of bounds values even without use_clamp */
+    if (!(type == NODE_MIX_LIGHT || type == NODE_MIX_DODGE || type == NODE_MIX_BURN)) {
+      if (try_bypass_or_make_constant(color1_in, clamp)) {
+        return;
+      }
+    }
+  }
+
+  switch (type) {
+    case NODE_MIX_BLEND:
+      /* remove useless mix colors nodes */
+      if (color1_in->link && color2_in->link) {
+        if (color1_in->link == color2_in->link) {
+          try_bypass_or_make_constant(color1_in, clamp);
+          break;
+        }
+      }
+      else if (!color1_in->link && !color2_in->link) {
+        float3 color1 = node->get_float3(color1_in->socket_type);
+        float3 color2 = node->get_float3(color2_in->socket_type);
+        if (color1 == color2) {
+          try_bypass_or_make_constant(color1_in, clamp);
+          break;
+        }
+      }
+      /* remove no-op mix color node when factor is 1.0 */
+      if (fac_is_one) {
+        try_bypass_or_make_constant(color2_in, clamp);
+        break;
+      }
+      break;
+    case NODE_MIX_ADD:
+      /* 0 + X (fac 1) == X */
+      if (is_zero(color1_in) && fac_is_one) {
+        try_bypass_or_make_constant(color2_in, clamp);
+      }
+      /* X + 0 (fac ?) == X */
+      else if (is_zero(color2_in)) {
+        try_bypass_or_make_constant(color1_in, clamp);
+      }
+      break;
+    case NODE_MIX_SUB:
+      /* X - 0 (fac ?) == X */
+      if (is_zero(color2_in)) {
+        try_bypass_or_make_constant(color1_in, clamp);
+      }
+      /* X - X (fac 1) == 0 */
+      else if (color1_in->link && color1_in->link == color2_in->link && fac_is_one) {
+        make_zero();
+      }
+      break;
+    case NODE_MIX_MUL:
+      /* X * 1 (fac ?) == X, 1 * X (fac 1) == X */
+      if (is_one(color1_in) && fac_is_one) {
+        try_bypass_or_make_constant(color2_in, clamp);
+      }
+      else if (is_one(color2_in)) {
+        try_bypass_or_make_constant(color1_in, clamp);
+      }
+      /* 0 * ? (fac ?) == 0, ? * 0 (fac 1) == 0 */
+      else if (is_zero(color1_in)) {
+        make_zero();
+      }
+      else if (is_zero(color2_in) && fac_is_one) {
+        make_zero();
+      }
+      break;
+    case NODE_MIX_DIV:
+      /* X / 1 (fac ?) == X */
+      if (is_one(color2_in)) {
+        try_bypass_or_make_constant(color1_in, clamp);
+      }
+      /* 0 / ? (fac ?) == 0 */
+      else if (is_zero(color1_in)) {
+        make_zero();
+      }
+      break;
+    default:
+      break;
+  }
+}
+
 void ConstantFolder::fold_math(NodeMathType type) const
 {
   ShaderInput *value1_in = node->input("Value1");
diff --git a/intern/cycles/scene/constant_fold.h b/intern/cycles/scene/constant_fold.h
index 090ce367e6c..246ff2d31ee 100644
--- a/intern/cycles/scene/constant_fold.h
+++ b/intern/cycles/scene/constant_fold.h
@@ -51,6 +51,7 @@ class ConstantFolder {
 
   /* Specific nodes. */
   void fold_mix(NodeMix type, bool clamp) const;
+  void fold_mix_color(NodeMix type, bool clamp_factor, bool clamp) const;
   void fold_math(NodeMathType type) const;
   void fold_vector_math(NodeVectorMathType type) const;
   void fold_mapping(NodeMappingType type) const;
diff --git a/intern/cycles/scene/shader_nodes.cpp b/intern/cycles/scene/shader_nodes.cpp
index bedb0fe2902..a9cd453947b 100644
--- a/intern/cycles/scene/shader_nodes.cpp
+++ b/intern/cycles/scene/shader_nodes.cpp
@@ -4950,7 +4950,7 @@ NODE_DEFINE(MixNode)
   type_enum.insert("hue", NODE_MIX_HUE);
   type_enum.insert("saturation", NODE_MIX_SAT);
   type_enum.insert("value", NODE_MIX_VAL);
-  type_enum.insert("color", NODE_MIX_COLOR);
+  type_enum.insert("color", NODE_MIX_COL);
   type_enum.insert("soft_light", NODE_MIX_SOFT);
   type_enum.insert("linear_light", NODE_MIX_LINEAR);
   SOCKET_ENUM(mix_type, "Type", type_enum, NODE_MIX_BLEND);
@@ -4999,13 +4999,253 @@ void MixNode::compile(OSLCompiler &compiler)
 void MixNode::constant_fold(const ConstantFolder &folder)
 {
   if (folder.all_inputs_constant()) {
-    folder.make_constant_clamp(svm_mix(mix_type, fac, color1, color2), use_clamp);
+    folder.make_constant_clamp(svm_mix_clamped_factor(mix_type, fac, color1, color2), use_clamp);
   }
   else {
     folder.fold_mix(mix_type, use_clamp);
   }
 }
 
+/* Mix Color */
+
+NODE_DEFINE(MixColorNode)
+{
+  NodeType *type = NodeType::add("mix_color", create, NodeType::SHADER);
+
+  static NodeEnum type_enum;
+  type_enum.insert("mix", NODE_MIX_BLEND);
+  type_enum.insert("add", NODE_MIX_ADD);
+  type_enum.insert("multiply", NODE_MIX_MUL);
+  type_enum.insert("screen", NODE_MIX_SCREEN);
+  type_enum.insert("overlay", NODE_MIX_OVERLAY);
+  type_enum.insert("subtract", NODE_MIX_SUB);
+  type_enum.insert("divide", NODE_MIX_DIV);
+  type_enum.insert("difference", NODE_MIX_DIFF);
+  type_enum.insert("darken", NODE_MIX_DARK);
+  type_enum.insert("lighten", NODE_MIX_LIGHT);
+  type_enum.insert("dodge", NODE_MIX_DODGE);
+  type_enum.insert("burn", NODE_MIX_BURN);
+  type_enum.insert("hue", NODE_MIX_HUE);
+  type_enum.insert("saturation", NODE_MIX_SAT);
+  type_enum.insert("value", NODE_MIX_VAL);
+  type_enum.insert("color", NODE_MIX_COL);
+  type_enum.insert("soft_light", NODE_MIX_SOFT);
+  type_enum.insert("linear_light", NODE_MIX_LINEAR);
+  SOCKET_ENUM(blend_type, "Type", type_enum, NODE_MIX_BLEND);
+
+  SOCKET_IN_FLOAT(fac, "Factor", 0.5f);
+  SOCKET_IN_COLOR(a, "A", zero_float3());
+  SOCKET_IN_COLOR(b, "B", zero_float3());
+  SOCKET_BOOLEAN(use_clamp_result, "Use Clamp Result", false);
+  SOCKET_BOOLEAN(use_clamp, "Use Clamp", true);
+
+  SOCKET_OUT_COLOR(result, "Result");
+
+  return type;
+}
+
+MixColorNode::MixColorNode() : ShaderNode(get_node_type())
+{
+}
+
+void MixColorNode::compile(SVMCompiler &compiler)
+{
+  ShaderInput *fac_in = input("Factor");
+  ShaderInput *a_in = input("A");
+  ShaderInput *b_in = input("B");
+  ShaderOutput *result_out = output("Result");
+
+  int fac_in_stack_offset = compiler.stack_assign(fac_in);
+  int a_in_stack_offset = compiler.stack_assign(a_in);
+  int b_in_stack_offset = compiler.stack_assign(b_in);
+
+  compiler.add_node(
+      NODE_MIX_COLOR,
+      compiler.encode_uchar4(use_clamp, blend_type, use_clamp_result),
+      compiler.encode_uchar4(fac_in_stack_offset, a_in_stack_offset, b_in_stack_offset),
+      compiler.stack_assign(result_out));
+}
+
+void MixColorNode::compile(OSLCompiler &compiler)
+{
+  compiler.parameter(this, "blend_type");
+  compiler.parameter(this, "use_clamp");
+  compiler.parameter(this, "use_clamp_result");
+  compiler.add(this, "node_mix_color");
+}
+
+void MixColorNode::constant_fold(const ConstantFolder &folder)
+{
+  if (folder.all_inputs_constant()) {
+    if (use_clamp) {
+      fac = clamp(fac, 0.0f, 1.0f);
+    }
+    folder.make_constant_clamp(svm_mix(blend_type, fac, a, b), use_clamp_result);
+  }
+  else {
+    folder.fold_mix_color(blend_type, use_clamp, use_clamp_result);
+  }
+}
+
+/* Mix Float */
+
+NODE_DEFINE(MixFloatNode)
+{
+  NodeType *type = NodeType::add("mix_float", create, NodeType::SHADER);
+
+  SOCKET_IN_FLOAT(fac, "Factor", 0.5f);
+  SOCKET_IN_FLOAT(a, "A", 0.0f);
+  SOCKET_IN_FLOAT(b, "B", 0.0f);
+  SOCKET_BOOLEAN(use_clamp, "Use Clamp", true);
+  SOCKET_OUT_FLOAT(result, "Result");
+
+  return type;
+}
+
+MixFloatNode::MixFloatNode() : ShaderNode(get_node_type())
+{
+}
+
+void MixFloatNode::compile(SVMCompiler &compiler)
+{
+  ShaderInput *fac_in = input("Factor");
+  ShaderInput *a_in = input("A");
+  ShaderInput *b_in = input("B");
+  ShaderOutput *result_out = output("Result");
+
+  int fac_in_stack_offset = compiler.stack_assign(fac_in);
+  int a_in_stack_offset = compiler.stack_assign(a_in);
+  int b_in_stack_offset = compiler.stack_assign(b_in);
+
+  compiler.add_node(
+      NODE_MIX_FLOAT,
+      use_clamp,
+      compiler.encode_uchar4(fac_in_stack_offset, a_in_stack_offset, b_in_stack_offset),
+      compiler.stack_assign(result_out));
+}
+
+void MixFloatNode::compile(OSLCompiler &compiler)
+{
+  compiler.parameter(this, "use_clamp");
+  compiler.add(this, "node_mix_float");
+}
+
+void MixFloatNode::constant_fold(const ConstantFolder &folder)
+{
+  if (folder.all_inputs_constant()) {
+    if (use_clamp) {
+      fac = clamp(fac, 0.0f, 1.0f);
+    }
+    folder.make_constant(a * (1 - fac) + b * fac);
+  }
+}
+
+/* Mix Vector */
+
+NODE_DEFINE(MixVectorNode)
+{
+  NodeType *type = NodeType::add("mix_vector", create, NodeType::SHADER);
+
+  SOCKET_IN_FLOAT(fac, "Factor", 0.5f);
+  SOCKET_IN_VECTOR(a, "A", zero_float3());
+  SOCKET_IN_VECTOR(b, "B", zero_float3());
+  SOCKET_BOOLEAN(use_clamp, "Use Clamp", true);
+
+  SOCKET_OUT_VECTOR(result, "Result");
+
+  return type;
+}
+
+MixVectorNode::MixVectorNode() : ShaderNode(get_node_type())
+{
+}
+
+void MixVectorNode::compile(SVMCompiler &compiler)
+{
+  ShaderInput *fac_in = input("Factor");
+  ShaderInput *a_in = input("A");
+  ShaderInput *b_in = input("B");
+  ShaderOutput *result_out = output("Result");
+
+  int fac_in_stack_offset = compiler.stack_assign(fac_in);
+  int a_in_stack_offset = compiler.stack_assign(a_in);
+  int b_in_stack_offset = compiler.stack_assign(b_in);
+
+  compiler.add_node(
+      NODE_MIX_VECTOR,
+      compiler.encode_uchar4(use_clamp, fac_in_stack_offset, a_in_stack_offset, b_in_stack_offset),
+      compiler.stack_assign(result_out));
+}
+
+void MixVectorNode::compile(OSLCompiler &compiler)
+{
+  compiler.parameter(this, "use_clamp");
+  compiler.add(this, "node_mix_vector");
+}
+
+void MixVectorNode::constant_fold(const ConstantFolder &folder)
+{
+  if (folder.all_inputs_constant()) {
+    if (use_clamp) {
+      fac = clamp(fac, 0.0f, 1.0f);
+    }
+    folder.make_constant(a * (one_float3() - fac) + b * fac);
+  }
+}
+
+/* Mix Vector Non Uniform */
+
+NODE_DEFINE(MixVectorNonUniformNode)
+{
+  NodeType *type = NodeType::add("mix_vector_non_uniform", create, NodeType::SHADER);
+
+  SOCKET_IN_VECTOR(fac, "Factor", make_float3(0.5f, 0.5f, 0.5f));
+  SOCKET_IN_VECTOR(a, "A", zero_float3());
+  SOCKET_IN_VECTOR(b, "B", zero_float3());
+  SOCKET_BOOLEAN(use_clamp, "Use Clamp", true);
+
+  SOCKET_OUT_VECTOR(result, "Result");
+
+  return type;
+}
+
+MixVectorNonUniformNode::MixVectorNonUniformNode() : ShaderNode(get_node_type())
+{
+}
+
+void MixVectorNonUniformNode::compile(SVMCompiler &compiler)
+{
+  ShaderInput *fac_in = input("Factor");
+  ShaderInput *a_in = input("A");
+  ShaderInput *b_in = input("B");
+  ShaderOutput *result_out = output("Result");
+
+  int fac_in_stack_offset = compiler.stack_assign(fac_in);
+  int a_in_stack_offset = compiler.stack_assign(a_in);
+  int b_in_stack_offset = compiler.stack_assign(b_in);
+
+  compiler.add_node(
+      NODE_MIX_VECTOR_NON_UNIFORM,
+      compiler.encode_uchar4(use_clamp, fac_in_stack_offset, a_in_stack_offset, b_in_stack_offset),
+      compiler.stack_assign(result_out));
+}
+
+void MixVectorNonUniformNode::compile(OSLCompiler &compiler)
+{
+  compiler.parameter(this, "use_clamp");
+  compiler.add(this, "node_mix_vector_non_uniform");
+}
+
+void MixVectorNonUniformNode::constant_fold(const ConstantFolder &folder)
+{
+  if (folder.all_inputs_constant()) {
+    if (use_clamp) {
+      fac = saturate(fac);
+    }
+    folder.make_constant(a * (one_float3() - fac) + b * fac);
+  }
+}
+
 /* Combine Color */
 
 NODE_DEFINE(CombineColorNode)
diff --git a/intern/cycles/scene/shader_nodes.h b/intern/cycles/scene/shader_nodes.h
index ac40a397c1e..cc3a71a0697 100644
--- a/intern/cycles/scene/shader_nodes.h
+++ b/intern/cycles/scene/shader_nodes.h
@@ -1101,6 +1101,52 @@ class MixNode : public ShaderNode {
   NODE_SOCKET_API(float, fac)
 };
 
+class MixColorNode : public ShaderNode {
+ public:
+  SHADER_NODE_CLASS(MixColorNode)
+  void constant_fold(const ConstantFolder &folder);
+
+  NODE_SOCKET_API(float3, a)
+  NODE_SOCKET_API(float3, b)
+  NODE_SOCKET_API(float, fac)
+  NODE_SOCKET_API(bool, use_clamp)
+  NODE_SOCKET_API(bool, use_clamp_result)
+  NODE_SOCKET_API(NodeMix, blend_type)
+};
+
+class MixFloatNode : public ShaderNode {
+ public:
+  SHADER_NODE_CLASS(MixFloatNode)
+  void constant_fold(const ConstantFolder &folder);
+
+  NODE_SOCKET_API(float, a)
+  NODE_SOCKET_API(float, b)
+  NODE_SOCKET_API(float, fac)
+  NODE_SOCKET_API(bool, use_clamp)
+};
+
+class MixVectorNode : public ShaderNode {
+ public:
+  SHADER_NODE_CLASS(MixVectorNode)
+  void constant_fold(const ConstantFolder &folder);
+
+  NODE_SOCKET_API(float3, a)
+  NODE_SOCKET_API(float3, b)
+  NODE_SOCKET_API(float, fac)
+  NODE_SOCKET_API(bool, use_clamp)
+};
+
+class MixVectorNonUniformNode : public ShaderNode {
+ public:
+  SHADER_NODE_CLASS(MixVectorNonUniformNode)
+  void constant_fold(const ConstantFolder &folder);
+
+  NODE_SOCKET_API(float3, a)
+  NODE_SOCKET_API(float3, b)
+  NODE_SOCKET_API(float3, fac)
+  NODE_SOCKET_API(bool, use_clamp)
+};
+
 class CombineColorNode : public ShaderNode {
  public:
   SHADER_NODE_CLASS(CombineColorNode)