From c43ab1217d17c42587f13802b7e970f00d403646 Mon Sep 17 00:00:00 2001
From: squidbus <175574877+squidbus@users.noreply.github.com>
Date: Mon, 1 Sep 2025 16:42:48 -0700
Subject: [PATCH] shader_recompiler: Relax dual source blending assert to allow
 up to two targets. (#3495)

---
 src/shader_recompiler/backend/spirv/spirv_emit_context.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp b/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp
index e7c1340ce..25d7c4773 100644
--- a/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp
+++ b/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp
@@ -658,8 +658,10 @@ void EmitContext::DefineOutputs() {
             frag_outputs[i] = GetAttributeInfo(num_format, id, num_components, true);
             ++num_render_targets;
         }
-        ASSERT_MSG(!runtime_info.fs_info.dual_source_blending || num_render_targets == 2,
-                   "Dual source blending enabled, there must be exactly two MRT exports");
+        // Dual source blending allows at most 2 render targets, one for each source.
+        // Fewer targets are allowed but the missing blending source values will be undefined.
+        ASSERT_MSG(!runtime_info.fs_info.dual_source_blending || num_render_targets <= 2,
+                   "Dual source blending enabled, there must be at most two MRT exports");
         break;
     }
     case LogicalStage::Geometry: {