Prevent initializing outline edges to out of bound values

When multisampling is enabled, outline edges were getting initialized to one of the primitive's X position. If the primitive was out of bounds, then the default position was out of bounds, which led to an initial out of bounds memory access. Added a clamp to fix the issue. Bug chromium:779364 Change-Id: I4661f4229ee28a3032c763ed18dde799d3c3926b Reviewed-on: https://swiftshader-review.googlesource.com/13528Tested-by: Alexis Hétu <sugoi@google.com> Reviewed-by: Nicolas Capens <nicolascapens@google.com>

Prevent initializing outline edges to out of bound values
7a8ed2e1 · Alexis Hetu · Alexis Hétu · 3d7c786f · 7a8ed2e1
Commit 7a8ed2e1 authored Nov 02, 2017 by Alexis Hetu Committed by Alexis Hétu Nov 02, 2017
Hide whitespace changes
Inline Side-by-side

Showing with 3 additions and 1 deletion

SetupRoutine.cpp src/Shader/SetupRoutine.cpp +3 -1

No files found.
--- a/src/Shader/SetupRoutine.cpp
+++ b/src/Shader/SetupRoutine.cpp
@@ -224,7 +224,9 @@ namespace sw

 				if(state.multiSample > 1)
 				{
-					Short x = Short((X[0] + 0xF) >> 4);
+					Int xMin = *Pointer<Int>(data + OFFSET(DrawData, scissorX0));
+					Int xMax = *Pointer<Int>(data + OFFSET(DrawData, scissorX1));
+					Short x = Short(Clamp((X[0] + 0xF) >> 4, xMin, xMax));

 					For(Int y = yMin - 1, y < yMax + 1, y++)
 					{