From 7a76f2ae77406feb29768e85f0e50affce928fac Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@noreply.localhost>
Date: Wed, 15 Feb 2023 23:54:51 +0100
Subject: [PATCH] Fix #104370: Draw: Don't request the same attribute more than
 once

Avoid running out of attributes when multiple material slots use the same one.

Cleanup:
Removes the return value from drw_attributes_add_request since it shouldn't be modified afterward and it's never used.
Avoid making copies of DRW_AttributeRequest in drw_attributes_has_request.

Co-authored-by: Miguel Pozo <pragma37@gmail.com>
Pull Request #104709
---
 source/blender/draw/intern/draw_attributes.cc | 33 ++++++++-----------
 source/blender/draw/intern/draw_attributes.hh | 10 +++---
 2 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/source/blender/draw/intern/draw_attributes.cc b/source/blender/draw/intern/draw_attributes.cc
index 553832b0bf6..e1d53844f5a 100644
--- a/source/blender/draw/intern/draw_attributes.cc
+++ b/source/blender/draw/intern/draw_attributes.cc
@@ -4,20 +4,15 @@
 #include "draw_attributes.hh"
 
 /* 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)
+static bool drw_attributes_has_request(const DRW_Attributes *requests,
+                                       const 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;
+    const DRW_AttributeRequest &src_req = requests->requests[i];
+    if (src_req.domain == req.domain && src_req.layer_index == req.layer_index &&
+        src_req.cd_type == req.cd_type) {
+      return true;
     }
-    if (src_req.layer_index != req.layer_index) {
-      continue;
-    }
-    if (src_req.cd_type != req.cd_type) {
-      continue;
-    }
-    return true;
   }
   return false;
 }
@@ -61,14 +56,15 @@ bool drw_attributes_overlap(const DRW_Attributes *a, const DRW_Attributes *b)
   return true;
 }
 
-DRW_AttributeRequest *drw_attributes_add_request(DRW_Attributes *attrs,
-                                                 const char *name,
-                                                 const eCustomDataType type,
-                                                 const int layer_index,
-                                                 const eAttrDomain domain)
+void 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;
+  if (attrs->num_requests >= GPU_MAX_ATTR ||
+      drw_attributes_has_request(attrs, {type, layer_index, domain})) {
+    return;
   }
 
   DRW_AttributeRequest *req = &attrs->requests[attrs->num_requests];
@@ -77,7 +73,6 @@ DRW_AttributeRequest *drw_attributes_add_request(DRW_Attributes *attrs,
   req->layer_index = layer_index;
   req->domain = domain;
   attrs->num_requests += 1;
-  return req;
 }
 
 bool drw_custom_data_match_attribute(const CustomData *custom_data,
diff --git a/source/blender/draw/intern/draw_attributes.hh b/source/blender/draw/intern/draw_attributes.hh
index 1449f7b3b8a..d5de4e1641b 100644
--- a/source/blender/draw/intern/draw_attributes.hh
+++ b/source/blender/draw/intern/draw_attributes.hh
@@ -60,11 +60,11 @@ void drw_attributes_merge(DRW_Attributes *dst,
 /* Return true if all requests in b are in a. */
 bool drw_attributes_overlap(const DRW_Attributes *a, const DRW_Attributes *b);
 
-DRW_AttributeRequest *drw_attributes_add_request(DRW_Attributes *attrs,
-                                                 const char *name,
-                                                 eCustomDataType data_type,
-                                                 int layer_index,
-                                                 eAttrDomain domain);
+void drw_attributes_add_request(DRW_Attributes *attrs,
+                                const char *name,
+                                eCustomDataType data_type,
+                                int layer_index,
+                                eAttrDomain domain);
 
 bool drw_custom_data_match_attribute(const CustomData *custom_data,
                                      const char *name,