d3d10core: Use unsafe_impl_from_ID3D10VertexShader for an app provided iface.

dlls/d3d10core/d3d10core_private.h

@@ -176,6 +176,7 @@ struct d3d10_vertex_shader
 
 HRESULT d3d10_vertex_shader_init(struct d3d10_vertex_shader *shader, struct d3d10_device *device,
         const void *byte_code, SIZE_T byte_code_length) DECLSPEC_HIDDEN;
+struct d3d10_vertex_shader *unsafe_impl_from_ID3D10VertexShader(ID3D10VertexShader *iface) DECLSPEC_HIDDEN;
 
 /* ID3D10GeometryShader */
 struct d3d10_geometry_shader

dlls/d3d10core/device.c

@@ -151,7 +151,7 @@ static void STDMETHODCALLTYPE d3d10_device_VSSetShader(ID3D10Device *iface,
         ID3D10VertexShader *shader)
 {
     struct d3d10_device *This = impl_from_ID3D10Device(iface);
-    struct d3d10_vertex_shader *vs = (struct d3d10_vertex_shader *)shader;
+    struct d3d10_vertex_shader *vs = unsafe_impl_from_ID3D10VertexShader(shader);
 
     TRACE("iface %p, shader %p\n", iface, shader);
 

dlls/d3d10core/shader.c

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "wine/port.h"
+#include <assert.h>
 
 #include "d3d10core_private.h"
 
@@ -132,6 +133,11 @@ void shader_free_signature(struct wined3d_shader_signature *s)
     HeapFree(GetProcessHeap(), 0, s->elements);
 }
 
+static inline struct d3d10_vertex_shader *impl_from_ID3D10VertexShader(ID3D10VertexShader *iface)
+{
+    return CONTAINING_RECORD(iface, struct d3d10_vertex_shader, vtbl);
+}
+
 /* IUnknown methods */
 
 static HRESULT STDMETHODCALLTYPE d3d10_vertex_shader_QueryInterface(ID3D10VertexShader *iface,
@@ -267,6 +273,15 @@ HRESULT d3d10_vertex_shader_init(struct d3d10_vertex_shader *shader, struct d3d1
     return S_OK;
 }
 
+struct d3d10_vertex_shader *unsafe_impl_from_ID3D10VertexShader(ID3D10VertexShader *iface)
+{
+    if (!iface)
+        return NULL;
+    assert(iface->lpVtbl == &d3d10_vertex_shader_vtbl);
+
+    return impl_from_ID3D10VertexShader(iface);
+}
+
 static inline struct d3d10_geometry_shader *impl_from_ID3D10GeometryShader(ID3D10GeometryShader *iface)
 {
     return CONTAINING_RECORD(iface, struct d3d10_geometry_shader, ID3D10GeometryShader_iface);