vulkan: repack 69-byte vertices without dynamic vertex input on MoltenVK

e38b738b84 repacks the 69-byte vertex stride to 72 only with dynamic
vertex input, unless EGLANTINE_EXPERIMENTAL_STATIC_VERTEX_REPACK=1.
MoltenVK has no VK_EXT_vertex_input_dynamic_state and Metal needs strides
that are a multiple of 4, so the stride was never fixed on Macs.

Enable the static path automatically when the device's minimum vertex
binding stride alignment does not divide 69. The device reports 4 for
MoltenVK, matching its portability subset limit. The environment variable
still overrides it: 1 forces the repack on, 0 forces it off.

Assisted-by: Claude Sonnet 5.5 (implementation and commit message)

1 files changed, 6 insertions, 1 deletions

diff --git a/src/tests/video_core/vertex_repack.cpp b/src/tests/video_core/vertex_repack.cpp
index 3705a97926..5e21e3714c 100644
--- a/src/tests/video_core/vertex_repack.cpp
+++ b/src/tests/video_core/vertex_repack.cpp
@@ -76,10 +76,15 @@ TEST_CASE("Vertex repacking requires the captured tail and stride", "[vertex_rep
     REQUIRE(Vulkan::VertexRepackMask(regs) == 0);
 }
 
-TEST_CASE("Static vertex repacking requires explicit experimental opt-in", "[vertex_repack]") {
+TEST_CASE("Static vertex repacking follows the device stride alignment", "[vertex_repack]") {
     REQUIRE(Vulkan::VertexRepackInputSupported(true, false));
     REQUIRE_FALSE(Vulkan::VertexRepackInputSupported(false, false));
     REQUIRE(Vulkan::VertexRepackInputSupported(false, true));
+    REQUIRE_FALSE(Vulkan::StaticVertexRepackSelected(nullptr, 1));
+    REQUIRE(Vulkan::StaticVertexRepackSelected(nullptr, 4));
+    REQUIRE(Vulkan::StaticVertexRepackSelected("1", 1));
+    REQUIRE_FALSE(Vulkan::StaticVertexRepackSelected("0", 4));
+    REQUIRE(Vulkan::StaticVertexRepackSelected("other", 4));
 }
 
 TEST_CASE("Vertex repack planning keeps descriptor offsets aligned", "[vertex_repack]") {