From d91f340c869a1496804a3a2fff493e0ae60c8b53 Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Mon, 2 Jan 2023 18:21:04 -0800
Subject: [PATCH] VertexManagerBase: Move free space check to after the buffer
 is reset

Fixes incorrect logspam when the buffer needed to be reset on flushes (which we already were doing, but 52feed04dbf9d487138944ed834bd877620eef74 moved it to after the check was made). This is https://bugs.dolphin-emu.org/issues/10312.

I also converted it to an assert, as if this does happen, things are going to render incorrectly, so we want to make it obvious.
---
 Source/Core/VideoCommon/VertexManagerBase.cpp | 38 ++++++++++---------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/Source/Core/VideoCommon/VertexManagerBase.cpp b/Source/Core/VideoCommon/VertexManagerBase.cpp
index 88d7c47fba..85e2b48556 100644
--- a/Source/Core/VideoCommon/VertexManagerBase.cpp
+++ b/Source/Core/VideoCommon/VertexManagerBase.cpp
@@ -140,26 +140,11 @@ DataReader VertexManagerBase::PrepareForAdditionalData(OpcodeDecoder::Primitive
   }
 
   // Check for size in buffer, if the buffer gets full, call Flush()
-  if (!m_is_flushed &&
-      (count > m_index_generator.GetRemainingIndices(primitive) ||
-       count > GetRemainingIndices(primitive) || needed_vertex_bytes > GetRemainingSize()))
+  if (!m_is_flushed && (count > m_index_generator.GetRemainingIndices(primitive) ||
+                        count > GetRemainingIndices(primitive) ||
+                        needed_vertex_bytes > GetRemainingSize())) [[unlikely]]
   {
     Flush();
-
-    if (count > m_index_generator.GetRemainingIndices(primitive))
-    {
-      ERROR_LOG_FMT(VIDEO, "Too little remaining index values. Use 32-bit or reset them on flush.");
-    }
-    if (count > GetRemainingIndices(primitive))
-    {
-      ERROR_LOG_FMT(VIDEO, "VertexManager: Buffer not large enough for all indices! "
-                           "Increase MAXIBUFFERSIZE or we need primitive breaking after all.");
-    }
-    if (needed_vertex_bytes > GetRemainingSize())
-    {
-      ERROR_LOG_FMT(VIDEO, "VertexManager: Buffer not large enough for all vertices! "
-                           "Increase MAXVBUFFERSIZE or we need primitive breaking after all.");
-    }
   }
 
   m_cull_all = cullall;
@@ -182,6 +167,23 @@ DataReader VertexManagerBase::PrepareForAdditionalData(OpcodeDecoder::Primitive
     m_is_flushed = false;
   }
 
+  // Now that we've reset the buffer, there should be enough space. It's possible that we still
+  // won't have enough space in a few rare cases, such as vertex shader line/point expansion with a
+  // ton of lines in one draw command, in which case we will either need to add support for
+  // splitting a single draw command into multiple draws or using bigger indices.
+  ASSERT_MSG(VIDEO, count <= m_index_generator.GetRemainingIndices(primitive),
+             "VertexManager: Too few remaining index values ({} > {}). "
+             "32-bit indices or primitive breaking needed.",
+             count, m_index_generator.GetRemainingIndices(primitive));
+  ASSERT_MSG(VIDEO, count <= GetRemainingIndices(primitive),
+             "VertexManager: Buffer not large enough for all indices! ({} > {}) "
+             "Increase MAXIBUFFERSIZE or we need primitive breaking after all.",
+             count, GetRemainingIndices(primitive));
+  ASSERT_MSG(VIDEO, needed_vertex_bytes <= GetRemainingSize(),
+             "VertexManager: Buffer not large enough for all vertices! ({} > {}) "
+             "Increase MAXVBUFFERSIZE or we need primitive breaking after all.",
+             needed_vertex_bytes, GetRemainingSize());
+
   return DataReader(m_cur_buffer_pointer, m_end_buffer_pointer);
 }