From dcb82432fbc487cea4bd7980424cabf705529e3c Mon Sep 17 00:00:00 2001
From: James Price <jrprice@google.com>
Date: Thu, 17 Jun 2021 08:08:58 +0000
Subject: [PATCH] Metal: Remap vertex buffers when using Tint

Otherwise bindings with non-zero groups get through to the Tint MSL
backend and break assumptions.

Bug: tint:104, dawn:571
Change-Id: I8d95ba142a386ff0d992ffe5f88a7acf93057ce1
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/54960
Auto-Submit: James Price <jrprice@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
---
 src/dawn_native/metal/ShaderModuleMTL.mm | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/dawn_native/metal/ShaderModuleMTL.mm b/src/dawn_native/metal/ShaderModuleMTL.mm
index 80c7e88f77..82f7096a11 100644
--- a/src/dawn_native/metal/ShaderModuleMTL.mm
+++ b/src/dawn_native/metal/ShaderModuleMTL.mm
@@ -112,9 +112,14 @@ namespace dawn_native { namespace metal {
             for (VertexBufferSlot slot :
                  IterateBitSet(renderPipeline->GetVertexBufferSlotsUsed())) {
                 uint32_t metalIndex = renderPipeline->GetMtlVertexBufferIndex(slot);
-                DAWN_UNUSED(metalIndex);
-                // TODO(crbug.com/tint/104): Tell Tint to map (kPullingBufferBindingSet, slot) to
-                // this MSL buffer index.
+
+                // Tell Tint to map (kPullingBufferBindingSet, slot) to this MSL buffer index.
+                BindingPoint srcBindingPoint{static_cast<uint32_t>(kPullingBufferBindingSet),
+                                             static_cast<uint8_t>(slot)};
+                BindingPoint dstBindingPoint{0, metalIndex};
+                if (srcBindingPoint != dstBindingPoint) {
+                    bindingPoints.emplace(srcBindingPoint, dstBindingPoint);
+                }
             }
         }
         if (GetDevice()->IsRobustnessEnabled()) {