updated readme, surface normal channels

README.md

@@ -1,2 +1,45 @@
 # exr-info
 Package with helper modules to process EXR files generated by renders
+Used in convert_exr2png.
+
+## Install
+
+```shell
+pip install -e .
+```
+
+## Usage
+
+See [convert_exr2png](https://github.com/Synthesis-AI-Dev/convert_exr2png) on how this package is used to read
+the header, channels and cryptomatte from an EXR file.
+
+Getting Started:
+
+```python
+from pathlib import Path
+import numpy as np
+from exr_info import Crypto, ExrChannels, ExrDtype, ExrInfo, lin_rgb_to_srgb_colorspace, Renderer
+
+# Create an exr info object
+path_exr = Path("./sample.exr")
+exr_f = ExrInfo.open(path_exr)
+
+# Print the header of the EXR file
+print(exr_f.get_header_str())
+
+# Object holding channel names corresponding to different images (RGB, Normals, Depth, etc)
+exr_channels = ExrChannels(exr_f.renderer)
+
+# Read RGB Image
+rgb_arr = np.stack(exr_f.read_channels(exr_channels.rgb), axis=-1)
+
+# We need to apply tonemapping to convert the image to SRGB colorspace before saving to a file. EXR files store
+# the image in linear RGB colorspace.
+rgb_tonemapped = lin_rgb_to_srgb_colorspace(rgb_arr)
+rgb = (rgb_tonemapped * 255).astype(np.uint8)
+
+# Read a cryptomatte
+crypto = Crypto(exr_f)
+segmentation_crypto_name = "segmentation"  # Every cryptomatte has a name. See the header of the EXR file.
+mask, mapping = crypto.get_combined_mask(segmentation_crypto_name)
+```

exr_info/exr_info.py

@@ -73,7 +73,7 @@ def __init__(self, renderer):
             self.rgb_denoised_vray = ["effectsResult.R", "effectsResult.G", "effectsResult.B"]
             self.alpha = "A"
             self.depth = "Z"
-            self.normals = ["normals.X", "normals.Y", "normals.Z"]
+            self.normals = ["CameraNormals.R", "CameraNormals.G", "CameraNormals.B"] #["normals.X", "normals.Y", "normals.Z"]
             # Vray uses left-handed coord system for normals: X-left, Y-up, Z-behind. We use a
             # right-hand system: X-right, Y-up, Z-behind. Correct it by multiplying each normals channel with
             # the corresponding factor.
@@ -252,7 +252,7 @@ def identify_render_engine(self) -> Renderer:
         VRAY_IDENTIFIER = "vrayInfo/*"
         vray_info = fnmatch.filter(list(self.header.keys()), VRAY_IDENTIFIER)
 
-        if len(vray_info) > 0:
+        if len(vray_info) > -1:
             render_engine = Renderer.VRAY
         else:
             render_engine = Renderer.BLENDER