Various fixes to make `model-viewer` example almost working. (#1801)

* Fixing `PseudoPtr` legalization and `gfx` lifetime issues.

* Fixing `model-viewer` example.

This change contains various fixes to bring `model-viewer` example to fully functional. These fixes include:
1. Add `spReflectionTypeLayout_getSubObjectRangeSpaceOffset` function to return the space index for a sub object referenced through a `ParameterBlock` binding.
2. Make sure `D3D12Device` specifies column major matrix order creating a Slang session.
3. Fix `platform::Window::close()` and `platform::Application::quit()`.
4. Fix memory leak during `model-viewer''s model loading.
5. Fix command buffer recording in `model-viewer`.

With these changes, model viewer can now produce an image with a gray cube. The lighting is still incorrect becuase the `gfx` shader object implementation still does not handle "pending layout" resulting from global existential parameters.

* Fix d3d12 root signature creation.

* Use row-major matrix layout in model-viewer

1 files changed, 8 insertions, 0 deletions

diff --git a/slang.h b/slang.h
index 060ac2dce..df0a783be 100644
--- a/slang.h
+++ b/slang.h
@@ -2012,6 +2012,7 @@ extern "C"
 
     SLANG_API SlangInt spReflectionTypeLayout_getSubObjectRangeCount(SlangReflectionTypeLayout* typeLayout);
     SLANG_API SlangInt spReflectionTypeLayout_getSubObjectRangeBindingRangeIndex(SlangReflectionTypeLayout* typeLayout, SlangInt subObjectRangeIndex);
+    SLANG_API SlangInt spReflectionTypeLayout_getSubObjectRangeSpaceOffset(SlangReflectionTypeLayout* typeLayout, SlangInt subObjectRangeIndex);
 
 #if 0
     SLANG_API SlangInt spReflectionTypeLayout_getSubObjectRangeCount(SlangReflectionTypeLayout* typeLayout);
@@ -2687,6 +2688,13 @@ namespace slang
                 (SlangReflectionTypeLayout*) this,
                 subObjectRangeIndex);
         }
+
+        SlangInt getSubObjectRangeSpaceOffset(SlangInt subObjectRangeIndex)
+        {
+            return spReflectionTypeLayout_getSubObjectRangeSpaceOffset(
+                (SlangReflectionTypeLayout*) this,
+                subObjectRangeIndex);
+        }
     };
 
     struct Modifier