ofxAssimp vs. ofxAssimpModelLoader - Differences and performance

[dimitre]

I'm using back and forth both addons so I have the best of both worlds.
But I've noticed ofxAssimpModelLoader is much faster at loading complex models, like 11.36 seconds vs 32.35 seconds.

I'm sharing here the model if it helps debugging.
cr1.zip

I'm not sure if ofxAssimpModelLoader will be mantained,
but other differences I've noticed:
Y axis is inverted from one to another,
differences in scale
ofxAssimpModelLoader has some problems loading complex animations ( I can share the specic model if useful )

this tests are just the model inside a default easycam

[ofTheo]

@dimitre
Are you noticing those differences in Debug and Release or just Debug?

I thought it might be due to the differences between the two optimization flags, but they look the same:

ofxAssimp:
https://github.com/openframeworks/openFrameworks/blob/master/addons/ofxAssimp/src/Source/ofxAssimpSrcScene.cpp#L115-L128

And ofxAssimpModelLoader:
https://github.com/openframeworks/openFrameworks/blob/master/addons/ofxAssimpModelLoader/src/ofxAssimpModelLoader.cpp#L137-L150

[dimitre]

Everything tested on Release

[ofTheo]

@dimitre is it possible to share the textures that are missing?

I see with both version of ofxAssimp addons that it is looking for texture files.
The newer addon seems to be getting really caught up with the missing textures which might be the real cause of the issue with the slower loading times.

For example if I try two complex GLTF models, the newer version loads the FlightHelmet in 2.988 seconds.
The older ofxAssimpModelLoader addon loads the FlightHelmet in 4.03441 seconds, so 25% slower.

Here's the missing texture messages from the CR1 model:

[verbose] ofxAssimpModelLoader: loadGLResources(): loading mesh 2
[verbose] ofxAssimpModelLoader::loadGLResources: : mesh is one sided
[verbose] ofxAssimpModelLoader: loadGLResource(): loading Diffuse image from "Cr1/Concreto___01.png"
[ error ] ofxAssimpModelLoader: loadGLResource(): texture doesn't exist: "/Users/theo/Downloads/cr1/Cr1.obj" in "/Users/theo/Downloads/cr1/Cr1/Concreto___01.png"
[ error ] ofxAssimpModelLoader: loadGLResource(): couldn't load texture: "/Users/theo/Downloads/cr1/Cr1.obj" from "/Users/theo/Downloads/cr1/Cr1/Concreto___01.png"
[verbose] ofxAssimpModelLoader: loadGLResources(): loading mesh 3
[verbose] ofxAssimpModelLoader::loadGLResources: : mesh is one sided
[verbose] ofxAssimpModelLoader: loadGLResource(): loading Diffuse image from "Cr1/Concreto___01.png"
[ error ] ofxAssimpModelLoader: loadGLResource(): texture doesn't exist: "/Users/theo/Downloads/cr1/Cr1.obj" in "/Users/theo/Downloads/cr1/Cr1/Concreto___01.png"
[ error ] ofxAssimpModelLoader: loadGLResource(): couldn't load texture: "/Users/theo/Downloads/cr1/Cr1.obj" from "/Users/theo/Downloads/cr1/Cr1/Concreto___01.png"
[verbose] ofxAssimpModelLoader: loadGLResources(): loading mesh 4
[verbose] ofxAssimpModelLoader::loadGLResources: : mesh is one sided
[verbose] ofxAssimpModelLoader: loadGLResource(): loading Diffuse image from "Cr1/Asphalt_New.jpg"
[ error ] ofxAssimpModelLoader: loadGLResource(): texture doesn't exist: "/Users/theo/Downloads/cr1/Cr1.obj" in "/Users/theo/Downloads/cr1/Cr1/Asphalt_New.jpg"
[ error ] ofxAssimpModelLoader: loadGLResource(): couldn't load texture: "/Users/theo/Downloads/cr1/Cr1.obj" from "/Users/theo/Downloads/cr1/Cr1/Asphalt_New.jpg"
[verbose] ofxAssimpModelLoader: loadGLResources(): loading mesh 5
[verbose] ofxAssimpModelLoader::loadGLResources: : mesh is one sided
[verbose] ofxAssimpModelLoader: loadGLResource(): loading Diffuse image from "Cr1/_.jpg"
[ error ] ofxAssimpModelLoader: loadGLResource(): texture doesn't exist: "/Users/theo/Downloads/cr1/Cr1.obj" in "/Users/theo/Downloads/cr1/Cr1/_.jpg"
[ error ] ofxAssimpModelLoader: loadGLResource(): couldn't load texture: "/Users/theo/Downloads/cr1/Cr1.obj" from "/Users/theo/Downloads/cr1/Cr1/_.jpg"
[verbose] ofxAssimpModelLoader: loadGLResources(): loading mesh 6
[verbose] ofxAssimpModelLoader::loadGLResources: : mesh is one sided

[dimitre]

Great find. I don't have them I use without.
it would be great if we could set model.disableTextures(); before loading model.
I think there is something going on on SrcScene::processNodesRecursive:
we can see it trying to load the same texture over and over, so there is some optimization opportunity there :)

[ofTheo]

Agree on the disableTextures!!
And yes, I think the newer addon does get stuck in a recursive loop. :D
cc @NickHardeman

This is a good test case haha.

[NickHardeman]

Hi @dimitre, Thank you for posting about the issues. The newer one really tries its best to find the texture, maybe it should try less hard. ;)
You can control what is imported using the import settings, such as textures, materials, animations, etc.

openFrameworks/addons/ofxAssimp/src/Source/ofxAssimpSrcScene.h

Lines 34 to 47 in 44b6186

	struct ImportSettings {
	of::filesystem::path filePath;
	int assimpOptimizeFlags=OFX_ASSIMP_OPTIMIZE_DEFAULT;
	bool importAsTex2d = true;
	bool importTextures = true;
	bool importAnimations = true;
	bool importMaterials = true;
	bool fixInfacingNormals = false; // aiProcess_FixInfacingNormals
	// bool importLights = false;
	bool convertToLeftHanded = true; // aiProcess_ConvertToLeftHanded
	std::vector<std::string> excludeNodesContainingStrings;
	unsigned int aiFlags = 0; // ai process flags, ie. aiProcess_FixInfacingNormals
	};

[NickHardeman]

@dimitre, I can look into the caching of textures from the same location so it doesn't reload them a bunch; currently trying to get ofxSvg compiling on msys2 and VS....

[NickHardeman]

@dimitre, you were correct about the processNodesRecursive() function. It was searching through every mesh and looking for bones. Since the example scene you linked to is quite large, it was taking a long long time repeatedly going through all the meshes. Now caching the bones so the searching is much faster, especially for the cr1 scene, since there are now bones.
FIx #8281

[dimitre]

Closed by #8281

[dimitre]

Thanks @NickHardeman

[dimitre]

I'm now working again with Assimp, and have some thoughts maybe related to this issue.
I think in general 3d programs hold the texture for materials only once and make a reference in the models that are using it. it is like a pool of reusable textures.
from what I'm reading here ofxAssimp stores each texture in the mesh itself, so if I reuse the same texture in 100 meshes I suppose it will be copied all over right? @NickHardeman

[NickHardeman]

ofxAssimp stores the textures per scene using a hash constructed of the texture type and path. The texture is then passed along to the src mesh as a shared_ptr. So if the multiple meshes are being drawn using the same material / texture, it should ultimately point to the same texture in the cached texture map stored in ofxAssimpSrcScene.
It would be different if there are multiple ofxAssimp Scenes.

openFrameworks/addons/ofxAssimp/src/Source/ofxAssimpSrcScene.cpp

Lines 744 to 762 in f501852

	if(mTextureCacheMap.count(realPath) > 0) {
	// create a key using the type of texture and the path
	std::string assimpTexKey = texTypeString+"_"+realPath.string();
	std::shared_ptr<ofxAssimp::Texture> assimpTexture;
	if( mAssimpTextures.count(assimpTexKey) ) {
	assimpTexture = mAssimpTextures[assimpTexKey];
	} else {
	assimpTexture = std::make_shared<ofxAssimp::Texture>();
	assimpTexture->setup( realPath, bWrap );
	assimpTexture->setAiTextureType((aiTextureType)d);
	assimpTexture->setTexture(mTextureCacheMap[realPath]);
	mAssimpTextures[assimpTexKey] = assimpTexture;
	}
	if( assimpTexture ) {
	ofLogVerbose("ofxAssimp::SrcScene") << "adding texture type: " << texTypeString << " to mesh: " << aSrcMesh->getName();
	aSrcMesh->addTexture( assimpTexture );
	}
	}