2 files changed, 4 insertions, 3 deletions

diff --git a/src/video_core/primitive_assembly.cpp b/src/video_core/primitive_assembly.cpp
index be7377290..e71ff5719 100644
--- a/src/video_core/primitive_assembly.cpp
+++ b/src/video_core/primitive_assembly.cpp
@@ -14,7 +14,7 @@ PrimitiveAssembler<VertexType>::PrimitiveAssembler(Regs::TriangleTopology topolo
     : topology(topology), buffer_index(0) {}
 
 template <typename VertexType>
-void PrimitiveAssembler<VertexType>::SubmitVertex(VertexType& vtx,
+void PrimitiveAssembler<VertexType>::SubmitVertex(const VertexType& vtx,
                                                   TriangleHandler triangle_handler) {
     switch (topology) {
     // TODO: Figure out what's different with TriangleTopology::Shader.
diff --git a/src/video_core/primitive_assembly.h b/src/video_core/primitive_assembly.h
index 0384d5984..24da47382 100644
--- a/src/video_core/primitive_assembly.h
+++ b/src/video_core/primitive_assembly.h
@@ -15,7 +15,8 @@ namespace Pica {
  */
 template <typename VertexType>
 struct PrimitiveAssembler {
-    using TriangleHandler = std::function<void(VertexType& v0, VertexType& v1, VertexType& v2)>;
+    using TriangleHandler =
+        std::function<void(const VertexType& v0, const VertexType& v1, const VertexType& v2)>;
 
     PrimitiveAssembler(Regs::TriangleTopology topology = Regs::TriangleTopology::List);
 
@@ -25,7 +26,7 @@ struct PrimitiveAssembler {
      * NOTE: We could specify the triangle handler in the constructor, but this way we can
      * keep event and handler code next to each other.
      */
-    void SubmitVertex(VertexType& vtx, TriangleHandler triangle_handler);
+    void SubmitVertex(const VertexType& vtx, TriangleHandler triangle_handler);
 
     /**
      * Resets the internal state of the PrimitiveAssembler.