Save bake image as 32 bit float?

Coding Python Support
#1

I’m trying to implement 32 bit float as a feature for Principled Baker.
Right after baking the image properties says: “Image: size _ x _, RGB float”
But the saved image is always just 8 bit. Reloading the image (bpy.ops.image.reload()) shows the image properties as: “Image: size _ x _, RGB byte”

What am I missing?

The test scene is simple: just a cube with a material with an Emission node
This is the test code:

import bpy

mat_node_tree = bpy.context.active_object.material_slots['Material'].material.node_tree

image = bpy.data.images.new(name="test.tif", width=256, height=256, float_buffer=True)
image.filepath = "//test.tif"
image.file_format = 'TIFF'

image_node = mat_node_tree.nodes.new(type="ShaderNodeTexImage")
image_node.image = image
image_node.select = True
mat_node_tree.nodes.active = image_node

bpy.ops.object.bake(type='EMIT')

image.save()

should mentioning: I’m testing with Blender 2.80 beta

#2

I always save out normal maps I bake in a 32bit full float EXR larger than my target size. Makes a fat file, but for the likes of a normal map, you kinda want it. I’m not sure tif supports it. I was under the impression other formats were limited to 16 bit.

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#3

I forgot the mention that: Save the baked result manually gives at least 16 bit support with TIFF or PNG.
Maybe it’s that this only works with EXR.
But how to save as 16 bit?

#4

In the code? Not sure, but I also know that most game engines will drop a 16 bit image to 8 bit on import. When you save out an image it looks like ImageFormatSettings.color_depth is the correct parameter to set.

https://docs.blender.org/api/master/bpy.types.ImageFormatSettings.html?highlight=imageformat#bpy.types.ImageFormatSettings

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#5

Thank you for your help!

I got it half solved, but only for exr 32bit.
The problem was you have to set the file format (image.file_format) after baking.

Still having the problem how to save 16bit.

#6

Well, on that same ref doc it looks like before saving you would:

  • Set ImageFormatSettings.file_format to TIFF/PNG
  • Set ImageFormatSettings.color_depth to 16
  • Then image.save()
#7

That still does not work. Saving by hand works fine.

Here is the test code:

import bpy

mat_node_tree = bpy.context.active_object.material_slots['Material'].material.node_tree

img_name = "test.tif"
image = bpy.data.images.new(name=img_name, width=256, height=256, float_buffer=True)
image.filepath = "//"+img_name

image_node = mat_node_tree.nodes.new(type="ShaderNodeTexImage")
image_node.image = image
image_node.select = True
mat_node_tree.nodes.active = image_node

bpy.ops.object.bake(type='EMIT')

bpy.types.ImageFormatSettings.file_format = 'TIFF'
bpy.types.ImageFormatSettings.color_depth = '16'

image.save()
Principled Baker - Bake PBR textures with a few clicks
#8

Well, what you need is an example that works, yes? I know TexTools works and a brief look in there suggests that they should be separate methods. One to define the image params, one to bake that calls that method for the image.

#9

I already looked in the TexTools code. Surpise:

# image.save()

Saving is commented out in the code … :joy:

As far as I know, TexTools does not auto save images.

#10

Ah. I see. try these:

def BAKE_EMIT(self, context)
    TMP_SAMPLES = bpy.context.scene.cycles.samples
    bpy.context.scene.cycles.samples = 1 
    bpy.ops.object.bake(type='EMIT')
    bpy.context.scene.cycles.samples = TMP_SAMPLES

I’m not sure TMP_SAMPLES is needed, but I wouldn’t want to have someone’s render sample settings changed in the scene without putting it back to whatever they had it set at. That’s just rude :wink:
I’d test it both ways and see.

and for the textures…

    bpy.ops.image.save_as()

https://docs.blender.org/api/master/bpy.ops.image.html?highlight=save#bpy.ops.image.save_as

Looks like image.save() is to save changes to an existing image, perhaps.

#11

Thanks! Copy & Paste :stuck_out_tongue:
Till I put settings for samples in the add-on, you can set the samples in the render settings.

So, how do I use the operator on a certain image? Image objects don’t have .save_as() method.

#12

I had to poke around in the console to see what I was missing:

import bpy

def BAKE_EMIT():
    TMP_SAMPLES = bpy.context.scene.cycles.samples
    bpy.context.scene.cycles.samples = 1
    bpy.ops.object.bake(type='EMIT')
    bpy.context.scene.cycles.samples = TMP_SAMPLES


mat_node_tree = bpy.context.active_object.material_slots['Material'].material.node_tree

img_name = "test.exr"
image = bpy.data.images.new(name=img_name, width=1024, height=1024, float_buffer=True)
image.filepath = "//"+img_name

image_node = mat_node_tree.nodes.new(type="ShaderNodeTexImage")
image_node.image = image
image_node.color_space = 'NONE'
image_node.select = True
mat_node_tree.nodes.active = image_node

BAKE_EMIT()

bpy.data.images[img_name].file_format = 'OPEN_EXR'

image.save()

Haven’t figured out how to control 8/16 bit yet, but there’s a 32 bit full float exr.

Edit: and here’s the problem: https://blender.stackexchange.com/questions/27317/saving-a-16-bit-png-using-script

So, you’d have to create a temporary scene and use render settings to do it.

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#13

I got it now working with changing the bpy.context.scene.render.image_settings and saving with image.save_render(filepath).
I’ll implement this over the weekend and post simple code as a solution.

Thanks for your help!