Mesh shader support (#2464)

* Add gdb generated files to .gitignore

* Switch to c++17

TODO: Ellie update coding style doc

* WIP mesh shaders

* Add MeshOutputType and mesh output decorations

* Lift array type layout creation out of _createTypeLayout

in preparation for sharing it elsewhere

* Initial pass at GLSL legalization for mesh shaders

* Create output types for builtin mesh outputs

This should be rendered as an out paramter block

* Handle writes to member fields in mesh shader output

* Per primitive output from mesh shaders

* Add mesh shader tests

* Redeclare mesh output builtins

* Remove unused instruction

* Emit explicit mesh output max max size

* Add unimplemented warning for array members in mesh output

* Implement mesh output splitting for GLSL in terms of getSubscriptVal

* Allow HLSL syntax for mesh output modifiers

* Improve error messages for mesh output

* Add test for HLSL style mesh output syntax

* Emit explicit mesh output indices max size

* HLSL generation support for mesh shaders

* Better errors for mesh shader misuse

* Neaten comments

* Regenerate vs2019 project files

* Fix build on vs2019

* Retreat on c++17

Will make the change in a separate PR

* slang-glslang binary dep 11.10.0 -> 11.12.0-32

* Fixes for msvc compiler

* Update msvc project

1 files changed, 51 insertions, 0 deletions

diff --git a/tests/pipeline/rasterization/mesh/nested-component-write.slang b/tests/pipeline/rasterization/mesh/nested-component-write.slang
new file mode 100644
index 000000000..68bb6dfb9
--- /dev/null
+++ b/tests/pipeline/rasterization/mesh/nested-component-write.slang
@@ -0,0 +1,51 @@
+// nested-component-write.slang
+
+// This tests that writing to individual components nested structs works for
+// mesh shader outputs.
+
+//TEST:CROSS_COMPILE:-target spirv -profile glsl_450+spirv_1_4 -entry main -stage mesh
+
+struct Foo
+{
+    float4 pos : SV_Position;
+    Bar bar;
+};
+
+struct Bar
+{
+    Baz baz : Color;
+};
+
+struct Baz
+{
+    float3 color;
+};
+
+struct Vertex
+{
+    Foo foo;
+};
+
+const static uint MAX_VERTS = 3;
+const static uint MAX_PRIMS = 1;
+
+[outputtopology("triangle")]
+[numthreads(3, 1, 1)]
+void main(
+    in uint tig : SV_GroupIndex,
+    out Vertices<Vertex, MAX_VERTS> verts,
+    out Indices<uint3, MAX_PRIMS> triangles
+    )
+{
+    SetMeshOutputCounts(3, 1);
+
+    if(tig < 3) {
+        verts[tig].foo.pos = float4(0, 0, 0, 1);
+        verts[tig].foo.bar.baz.color = float3(1, 2, 3);
+    }
+
+    if(tig < 1) {
+        triangles[tig] = uint3(0,1,2);
+    }
+}
+