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, 22 insertions, 0 deletions

diff --git a/tools/gfx/renderer-shared.cpp b/tools/gfx/renderer-shared.cpp
index 333f1df54..2a12b777c 100644
--- a/tools/gfx/renderer-shared.cpp
+++ b/tools/gfx/renderer-shared.cpp
@@ -183,6 +183,20 @@ IShaderProgram* gfx::ShaderProgramBase::getInterface(const Guid& guid)
     return nullptr;
 }
 
+IInputLayout* gfx::InputLayoutBase::getInterface(const Guid& guid)
+{
+    if (guid == GfxGUID::IID_ISlangUnknown || guid == GfxGUID::IID_IInputLayout)
+        return static_cast<IInputLayout*>(this);
+    return nullptr;
+}
+
+IFramebufferLayout* gfx::FramebufferLayoutBase::getInterface(const Guid& guid)
+{
+    if (guid == GfxGUID::IID_ISlangUnknown || guid == GfxGUID::IID_IFramebufferLayout)
+        return static_cast<IFramebufferLayout*>(this);
+    return nullptr;
+}
+
 IPipelineState* gfx::PipelineStateBase::getInterface(const Guid& guid)
 {
     if (guid == GfxGUID::IID_ISlangUnknown || guid == GfxGUID::IID_IPipelineState)
@@ -197,6 +211,14 @@ void PipelineStateBase::initializeBase(const PipelineStateDesc& inDesc)
     auto program = desc.getProgram();
     m_program = program;
     isSpecializable = (program->slangProgram && program->slangProgram->getSpecializationParamCount() != 0);
+
+    // Hold a strong reference to inputLayout and framebufferLayout objects to prevent it from
+    // destruction.
+    if (inDesc.type == PipelineType::Graphics)
+    {
+        inputLayout = static_cast<InputLayoutBase*>(inDesc.graphics.inputLayout);
+        framebufferLayout = static_cast<FramebufferLayoutBase*>(inDesc.graphics.framebufferLayout);
+    }
 }
 
 IDevice* gfx::RendererBase::getInterface(const Guid& guid)