1 files changed, 114 insertions, 0 deletions
diff --git a/source/blender/draw/intern/draw_attributes.cc b/source/blender/draw/intern/draw_attributes.cc
new file mode 100644
index 00000000000..3f187aef8e6
--- /dev/null
+++ b/source/blender/draw/intern/draw_attributes.cc
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2022 Blender Foundation. All rights reserved. */
+
+#include "draw_attributes.h"
+
+/* Return true if the given DRW_AttributeRequest is already in the requests. */
+static bool drw_attributes_has_request(const DRW_Attributes *requests, DRW_AttributeRequest req)
+{
+  for (int i = 0; i < requests->num_requests; i++) {
+    const DRW_AttributeRequest src_req = requests->requests[i];
+    if (src_req.domain != req.domain) {
+      continue;
+    }
+    if (src_req.layer_index != req.layer_index) {
+      continue;
+    }
+    if (src_req.cd_type != req.cd_type) {
+      continue;
+    }
+    return true;
+  }
+  return false;
+}
+
+static void drw_attributes_merge_requests(const DRW_Attributes *src_requests,
+                                          DRW_Attributes *dst_requests)
+{
+  for (int i = 0; i < src_requests->num_requests; i++) {
+    if (dst_requests->num_requests == GPU_MAX_ATTR) {
+      return;
+    }
+
+    if (drw_attributes_has_request(dst_requests, src_requests->requests[i])) {
+      continue;
+    }
+
+    dst_requests->requests[dst_requests->num_requests] = src_requests->requests[i];
+    dst_requests->num_requests += 1;
+  }
+}
+
+void drw_attributes_clear(DRW_Attributes *attributes)
+{
+  memset(attributes, 0, sizeof(DRW_Attributes));
+}
+
+void drw_attributes_merge(DRW_Attributes *dst,
+                          const DRW_Attributes *src,
+                          ThreadMutex *render_mutex)
+{
+  BLI_mutex_lock(render_mutex);
+  drw_attributes_merge_requests(src, dst);
+  BLI_mutex_unlock(render_mutex);
+}
+
+bool drw_attributes_overlap(const DRW_Attributes *a, const DRW_Attributes *b)
+{
+  for (int i = 0; i < b->num_requests; i++) {
+    if (!drw_attributes_has_request(a, b->requests[i])) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+DRW_AttributeRequest *drw_attributes_add_request(DRW_Attributes *attrs,
+                                                 const char *name,
+                                                 const eCustomDataType type,
+                                                 const int layer_index,
+                                                 const eAttrDomain domain)
+{
+  if (attrs->num_requests >= GPU_MAX_ATTR) {
+    return nullptr;
+  }
+
+  DRW_AttributeRequest *req = &attrs->requests[attrs->num_requests];
+  req->cd_type = type;
+  BLI_strncpy(req->attribute_name, name, sizeof(req->attribute_name));
+  req->layer_index = layer_index;
+  req->domain = domain;
+  attrs->num_requests += 1;
+  return req;
+}
+
+bool drw_custom_data_match_attribute(const CustomData *custom_data,
+                                     const char *name,
+                                     int *r_layer_index,
+                                     eCustomDataType *r_type)
+{
+  const eCustomDataType possible_attribute_types[7] = {
+      CD_PROP_BOOL,
+      CD_PROP_INT8,
+      CD_PROP_INT32,
+      CD_PROP_FLOAT,
+      CD_PROP_FLOAT2,
+      CD_PROP_FLOAT3,
+      CD_PROP_COLOR,
+  };
+
+  for (int i = 0; i < ARRAY_SIZE(possible_attribute_types); i++) {
+    const eCustomDataType attr_type = possible_attribute_types[i];
+    int layer_index = CustomData_get_named_layer(custom_data, attr_type, name);
+    if (layer_index == -1) {
+      continue;
+    }
+
+    *r_layer_index = layer_index;
+    *r_type = attr_type;
+    return true;
+  }
+
+  return false;
+}