Geometry Nodes: Point separate and attribute compare nodes

This patch adds two related nodes, a node for separating points
and mesh vertices based on a boolean attribute input, and a node
for creating boolean attributes with comparisons.

See the differential for an example file and video.

Point Separate (T83059)
The output in both geometries is just point data, contained in the mesh
and point cloud components, depending which components had data in the
input geometry. Any points with the mask attribute set to true will be
moved from the first geometry output to the second. This means that
for meshes, all edge and face data will be removed. Any point domain
attributes are moved to the correct output geometry as well.

Attribute Compare (T83057)
The attribute compare does the "Equal" and "Not Equal" operations by
comparing vectors and colors based on their distance from each other.
For other operations, the comparison is between the lengths of the
vector inputs. In general, the highest complexity data type is used
for the operation, and a new function to determine that is added.

Differential Revision: https://developer.blender.org/D9876

1 files changed, 34 insertions, 0 deletions

diff --git a/source/blender/nodes/NOD_math_functions.hh b/source/blender/nodes/NOD_math_functions.hh
index 70e4174a844..cc750f9595a 100644
--- a/source/blender/nodes/NOD_math_functions.hh
+++ b/source/blender/nodes/NOD_math_functions.hh
@@ -36,6 +36,7 @@ struct FloatMathOperationInfo {
 };
 
 const FloatMathOperationInfo *get_float_math_operation_info(const int operation);
+const FloatMathOperationInfo *get_float_compare_operation_info(const int operation);
 
 /**
  * This calls the `callback` with two arguments:
@@ -197,4 +198,37 @@ inline bool try_dispatch_float_math_fl_fl_fl_to_fl(const int operation, Callback
   return false;
 }
 
+/**
+ * This is similar to try_dispatch_float_math_fl_to_fl, just with a different callback signature.
+ */
+template<typename Callback>
+inline bool try_dispatch_float_math_fl_fl_to_bool(const FloatCompareOperation operation,
+                                                  Callback &&callback)
+{
+  const FloatMathOperationInfo *info = get_float_compare_operation_info(operation);
+  if (info == nullptr) {
+    return false;
+  }
+
+  /* This is just an utility function to keep the individual cases smaller. */
+  auto dispatch = [&](auto math_function) -> bool {
+    callback(math_function, *info);
+    return true;
+  };
+
+  switch (operation) {
+    case NODE_FLOAT_COMPARE_LESS_THAN:
+      return dispatch([](float a, float b) { return a < b; });
+    case NODE_FLOAT_COMPARE_LESS_EQUAL:
+      return dispatch([](float a, float b) { return a <= b; });
+    case NODE_FLOAT_COMPARE_GREATER_THAN:
+      return dispatch([](float a, float b) { return a > b; });
+    case NODE_FLOAT_COMPARE_GREATER_EQUAL:
+      return dispatch([](float a, float b) { return a >= b; });
+    default:
+      return false;
+  }
+  return false;
+}
+
 }  // namespace blender::nodes