From e7307455f66c758e7db637a7b6adeea11160bae8 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Wed, 11 Mar 2015 08:04:19 +0000
Subject: [PATCH] Fix a crash if vertex input is instanced, with instance rate
 of 0

* In this case, every input takes the first index, need to avoid divide
  by 0 error.
---
 renderdocui/Windows/BufferViewer.cs | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/renderdocui/Windows/BufferViewer.cs b/renderdocui/Windows/BufferViewer.cs
index 6c2d5c282..7d9d4b120 100644
--- a/renderdocui/Windows/BufferViewer.cs
+++ b/renderdocui/Windows/BufferViewer.cs
@@ -1404,9 +1404,14 @@ namespace renderdocui.Windows
                             Stream strm = state.m_Stream[bufferFormats[el].buffer];
                             BinaryReader read = state.m_Reader[bufferFormats[el].buffer];
 
-                            uint offs = input.Strides[bufferFormats[el].buffer] *
-                                (bufferFormats[el].perinstance ? (instance/(uint)bufferFormats[el].instancerate) : index)
-                                                + bufferFormats[el].offset;
+                            uint instIdx = 0;
+                            // for instancing, need to handle instance rate being 0 (every instance takes index 0 in that case)
+                            if (bufferFormats[el].perinstance)
+                                instIdx = bufferFormats[el].instancerate > 0 ? (instance / (uint)bufferFormats[el].instancerate) : 0;
+                            else
+                                instIdx = index;
+
+                            uint offs = input.Strides[bufferFormats[el].buffer] * instIdx + bufferFormats[el].offset;
 
                             if (!MeshView)
                                 offs += ByteOffset;
@@ -1681,9 +1686,14 @@ namespace renderdocui.Windows
                             Stream strm = state.m_Stream[bufferFormats[el].buffer];
                             BinaryReader read = state.m_Reader[bufferFormats[el].buffer];
 
-                            uint offs = input.Strides[bufferFormats[el].buffer] *
-                                (bufferFormats[el].perinstance ? (instance / (uint)bufferFormats[el].instancerate) : dataIndex)
-                                                + bufferFormats[el].offset;
+                            uint instIdx = 0;
+                            // for instancing, need to handle instance rate being 0 (every instance takes index 0 in that case)
+                            if (bufferFormats[el].perinstance)
+                                instIdx = bufferFormats[el].instancerate > 0 ? (instance / (uint)bufferFormats[el].instancerate) : 0;
+                            else
+                                instIdx = dataIndex;
+
+                            uint offs = input.Strides[bufferFormats[el].buffer] * instIdx + bufferFormats[el].offset;
 
                             if (!MeshView)
                                 offs += ByteOffset;