Equivalent GLSL gl_ModelViewMatrix from Irrlicht Transforms.

[de3000]

I am trying to find the GLSL gl_ModelViewMatrix by multiplying the matrices from getTransfom() but I am getting nowhere.
Debugging shaders is not fun so does anybody know or should i try more multiplying nightmare-inducing code?

[vitek]

I believe it should be...

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core::matrix4 m = driver->getTransform(ETS_VIEW); 
m              *= driver->getTransform(ETS_WORLD);

Travis

[de3000]

I believed it was that also but debugging my shader says its not (unless my debug code is wrong).

Setting callback

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virtual void OnSetConstants(irr::video::IMaterialRendererServices* services,irr::s32 userData)
{
	matrix4 world= services->getVideoDriver()->getTransform(video::ETS_PROJECTION);
	matrix4 proj= services->getVideoDriver()->getTransform(video::ETS_WORLD);
	matrix4 view= services->getVideoDriver()->getTransform(video::ETS_VIEW);
	services->setVertexShaderConstant("mWorld", world.pointer(), 16);
	services->setVertexShaderConstant("mProj", proj.pointer(), 16);
	services->setVertexShaderConstant("mView", view.pointer(), 16);
}

And in the shader
Debug.vert

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uniform mat4 mProj, mWorld, mView;
varying vec4 same;
void main()
{
	gl_Position =  ftransform();
	mat4 a,b,c;
	a=mWorld;
	b=mProj;
	c=mView;
	mat4 ab,ba,ac,bc,ca,cb;
	ab=a*b;
	ba=b*a;
	ac=a*c;
	bc=b*c;
	ca=c*a;
	cb=c*b;
	same.r=(gl_ModelViewMatrix==(bc))?1.0:0.0;
	same.g=(gl_ModelViewMatrix==(ca))?1.0:0.0;
	same.b=(gl_ModelViewMatrix==(cb))?1.0:0.0;
}

Debug.frag

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varying vec4 same;
void main()
{
	gl_Colour=same;
}

So basically I just set a channel to 1.0 if the matrices match up and from my output most objects appear blue except for one which is placed at the origin.

What I am trying to do is render a scene from one camera view (Camera A) and store gl_ModelViewMatrix*gl_Vertex and then from another view (Camera B) calculate cameraAModelViewMatrix*gl_Vertex so that a comparison can be done.

[BlindSide]

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matrix4 proj= services->getVideoDriver()->getTransform(video::ETS_WORLD); 

Lol.

[de3000]

Copy paste fail.

unless my debug code is wrong

Guess it is wrong. Still having trouble getting comparable results though.