Updated Adding OpenEXR (markdown)

Adding-OpenEXR.md

@@ -11,11 +11,69 @@ The DirectXTex auxiliary module for loading ``EXR`` files is in the [DirectXTexE
 
 For the ``DirectXTexEXR.cpp`` file, update the project property _Additional Include Directories_ to include the OpenEXR library headers.
 
-> If using the recommended scripts above, add ``.\openexr\local\include\OpenEXR``
+> If using the recommended scripts above, add ``.\local\include\OpenEXR``
 
 For the executables that build with this support, you need to update the project property _Additional Library Directories_ to include the OpenEXR libraries.
 
-> If using the recommended scripts above, add ``.\openexr\local\lib``
+> If using the recommended scripts above, add ``.\local\lib``
+
+# Functions
+
+# GetMetadataFromEXRFile
+Returns the _TexMetadata_ from a ``.EXR`` file.
+
+    HRESULT GetMetadataFromEXRFile( const wchar_t* szFile,
+                                    TexMetadata& metadata );
+
+# LoadFromEXRFile
+Loads a ``.EXR`` file.
+
+    HRESULT LoadFromEXRFile const wchar_t* szFile,
+                            TexMetadata* metadata, ScratchImage& image );
+
+* The data is always loaded as ``R16G16B16A16_FLOAT``.
+
+# SaveToEXRFile
+Saves a single image to a ``.EXR`` file.
+
+    HRESULT SaveToEXRFile( const Image& image, const wchar_t* szFile );
+
+* ``R16G16B16A16_FLOAT``, ``R32G32B32A32_FLOAT``, and ``R32G32B32_FLOAT`` data are supported for writing.
+
+# Parameters
+For the load functions, the _metadata_ parameter can be nullptr as this information is also available in the returned **ScratchImage**.
+
+# Examples
+
+This is a simple loading example. The ``EXR`` format cannot contain complicated multi-image formats, so the _TexMetadata_ info is redundant information.
+
+    auto image = std::make_unique<ScratchImage>();
+    HRESULT hr = LoadFromEXRFile( L"flowers.exr", nullptr, *image );
+    if ( FAILED(hr) )
+        // error
+
+A ``EXR`` file can only store one 2D image.
+
+    const Image* img = image->GetImage(0,0,0);
+    assert( img );
+    HRESULT hr = SaveToEXRFile( *img, L"NEW_IMAGE.EXR" );
+    if ( FAILED(hr) )
+        // error
+
+You can also save data directly from memory without using the intermediate **ScratchImage** at all. This example assumes a single 2D image is being written out.
+
+    Image img;
+    img.width = /*<width of pixel data>*/;
+    img.height = /*<height of pixel data>*/;
+    img.format = /* DXGI_FORMAT_R16G16B16A16_FLOAT,
+                    DXGI_FORMAT_R32G32B32A32_FLOAT
+                    or DXGI_FORMAT_R32G32B32_FLOAT */;
+    img.rowPitch = /*<number of bytes in a scanline of the source data>*/;
+    img.slicePitch = /*<number of bytes in the entire 2D image>*/;
+    img.pixels = /*<pointer to pixel data>*/;
+    HRESULT hr = SaveToEXRFile( img, L"NEW_IMAGE.EXR" );
+    if ( FAILED(hr) )
+        // error
 
 # Samples