[PATCH vkd3d] README: Expand on building and using vkd3d

[Andrew Eikum]

Signed-off-by: Andrew Eikum <aeikum at codeweavers.com>
---
 README | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/README b/README
index f353c36..0abaa08 100644
--- a/README
+++ b/README
@@ -4,3 +4,31 @@ The vkd3d 3D Graphics Library
 
 Vkd3d is a 3D graphics library built on top of Vulkan. It has an API very
 similar, but not identical, to Direct3D 12.
+
+==============
+Building vkd3d
+==============
+
+Vkd3d depends on SPIRV-Headers and Vulkan-Headers (>= 1.1.88).
+
+Vkd3d builds some of its headers from IDL files. If you are using the release
+tarballs, then these headers are pre-built and are included. If you are
+building from git, then they will be built at build-time using widl. By
+default, vkd3d will use the widl found in PATH.  If widl is not available or
+is not recent (>= 3.0 or so), then you can build Wine with "make tools/widl"
+to avoid building all of Wine. You can then point vkd3d's configure at that
+widl binary with WIDL=/path/to/widl.
+
+===========
+Using vkd3d
+===========
+
+Vkd3d can be used by projects that target D3D12 as a drop-in replacement at
+build-time with some modest source modifications. Or it can be used by Wine to
+run Windows applications that target D3D12.
+
+To build Wine with vkd3d for D3D12 support, first build and install vkd3d (see
+above for widl requirement) and then build Wine. Wine's configure should pick
+up on vkd3d if it is installed to the system, or you can use PKG_CONFIG_PATH
+to point Wine's configure script at vkd3d's pc-files located in a non-standard
+installation.
-- 
2.20.1