Mojo3D Vertex animation/morphing – how?

[DiffrenzyKeymaster]

I’d like to morph between two (or more) sets of vertices, keeping the triangles  intact.

I’m adding the vetices myself, so I haver their indexes.

How would I go about this?

[coconParticipant]

I tried something but I did not get any results, whoever wants to continue the search I will mention the details.

 

I went to mojo3d.graphics.mesh and I added this method (after the TransformVertices):

Monkey

Method TransformVertex(index:Int, position:Vec3f) If index > 0 Or index < _vbuffer.Length Return End Local matrix := New AffineMat4f(position) Local vertices := Cast<Vertex3f Ptr>(_vbuffer.Data) Local cofactor := matrix.m.Cofactor() vertices[index].position=matrix * vertices[index].position vertices[index].normal=(cofactor * vertices[index].normal).Normalize() vertices[index].tangent.XYZ=(cofactor * vertices[index].tangent.XYZ).Normalize() _vbuffer.Invalidate() _dirty|=Dirty.Bounds End

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Method TransformVertex(index:Int, position:Vec3f) If index > 0 Or index < _vbuffer.Length Return End Local matrix := New AffineMat4f(position) Local vertices := Cast<Vertex3f Ptr>(_vbuffer.Data) Local cofactor := matrix.m.Cofactor() vertices[index].position=matrix * vertices[index].position vertices[index].normal=(cofactor * vertices[index].normal).Normalize() vertices[index].tangent.XYZ=(cofactor * vertices[index].tangent.XYZ).Normalize() _vbuffer.Invalidate() _dirty|=Dirty.Bounds End

 

Then I did a rebuild:

Monkey

mx2cc_windows makemods mojo3d

1	mx2cc_windows makemods mojo3d

 

And then at the “makequad” example I added this on the update loop.

Monkey

Local position := New Vec3f(0, 0, 0) position.X = Sin(Now()) * 100 _model.Mesh.TransformVertex(0, position)

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Local position := New Vec3f(0, 0, 0) position.X = Sin(Now()) * 100 _model.Mesh.TransformVertex(0, position)

 

 

Unfortunately I did not get any results, but this is how it should be done. Once I get more familiar with the inner workings of the Mojo3D I will know better, but this is the first time I every looked at it.

[Mark SiblyKeymaster]

Ok, finally got around to doing something here.

The latest develop branch includes new versions of VertexBuffer and IndexBuffer and a new ‘Renderable’ entity class.

There’s also a ‘morpher.monkey2’ in mojo3d/tests dir that shows you how to create your own renderable entity classes. It’s hopefully quite sensible:

Monkey

Class Morpher Extends Renderable 'note: meshes must have same number of vertices and same indices. ' Method New( mesh0:Mesh,mesh1:Mesh,material:Material,parent:Entity=null ) Super.New( parent ) 'get mesh vertices - don't need entire meshes ' _vertices0=mesh0.GetVertices() _vertices1=mesh1.GetVertices() _material=material 'create vertexbuffer ' _vbuffer=New VertexBuffer( Vertex3f.Format,_vertices0.Length ) 'create and initialize indexbuffer ' Local indices:=mesh0.GetIndices( 0 ) _ibuffer=New IndexBuffer( IndexFormat.UINT32,indices.Length ) _ibuffer.SetIndices( indices.Data,0,indices.Length ) End Protected Method OnRender( rq:RenderQueue ) override Local alpha:=Sin( Now() )*.5+.5 'lock vertex buffer Local vp:=Cast<Vertex3f Ptr>( _vbuffer.Lock() ) For Local i:=0 Until _vbuffer.Length Local v:=_vertices0[i] 'interpolate position v.position=_vertices0[i].position.Blend( _vertices1[i].position,alpha ) 'interpolate normal v.normal=_vertices0[i].normal.Blend( _vertices1[i].normal,alpha ).Normalize() vp[i]=v Next 'invalidate all vertices _vbuffer.Invalidate() 'unlock vertices _vbuffer.Unlock() 'add renderop rq.AddRenderOp( _material,Self,_vbuffer,_ibuffer,3,_ibuffer.Length/3,0 ) End Private Field _vertices0:Vertex3f[] Field _vertices1:Vertex3f[] Field _material:Material Field _vbuffer:VertexBuffer Field _ibuffer:IndexBuffer Field _nvertices:Int End

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Class Morpher Extends Renderable           'note: meshes must have same number of vertices and same indices.         ' Method New( mesh0:Mesh,mesh1:Mesh,material:Material,parent:Entity=null ) Super.New( parent )   'get mesh vertices - don't need entire meshes                  ' _vertices0=mesh0.GetVertices() _vertices1=mesh1.GetVertices() _material=material 'create vertexbuffer ' _vbuffer=New VertexBuffer( Vertex3f.Format,_vertices0.Length ) 'create and initialize indexbuffer ' Local indices:=mesh0.GetIndices( 0 ) _ibuffer=New IndexBuffer( IndexFormat.UINT32,indices.Length ) _ibuffer.SetIndices( indices.Data,0,indices.Length ) End Protected Method OnRender( rq:RenderQueue ) override Local alpha:=Sin( Now() )*.5+.5 'lock vertex buffer Local vp:=Cast<Vertex3f Ptr>( _vbuffer.Lock() ) For Local i:=0 Until _vbuffer.Length Local v:=_vertices0[i]   'interpolate position v.position=_vertices0[i].position.Blend( _vertices1[i].position,alpha ) 'interpolate normal v.normal=_vertices0[i].normal.Blend( _vertices1[i].normal,alpha ).Normalize() vp[i]=v Next 'invalidate all vertices _vbuffer.Invalidate() 'unlock vertices _vbuffer.Unlock() 'add renderop rq.AddRenderOp( _material,Self,_vbuffer,_ibuffer,3,_ibuffer.Length/3,0 ) End Private Field _vertices0:Vertex3f[] Field _vertices1:Vertex3f[] Field _material:Material Field _vbuffer:VertexBuffer Field _ibuffer:IndexBuffer Field _nvertices:Int End

Basically, renderers need to implement OnRender() which is passed a ‘RenderQueue’ which you can add render ops to.

A render op is basically a combination of material,instance,vertexbuffer,indexbuffer and draw count etc.

Batching render ops like this allows for multiple render passes if necessary without having to call OnRender multiple times. It also potentially allows for ‘state sorting’ (doesn’t do that yet), better instancing using GL extensions (doesn’t do that yet either), and potentially culling. The render ops are also used to render shadow maps if Renderable.CastsShadow is true.

Renderable is now used by Model, Sprite and ParticleSystem, although there’s a big kludge in there for Sprites.

OnRender is called once per camera, and will probably get a camera param at some point. It would also be possible to have a ‘baked’ renderqueue that was camera independant and didn’t have to be rebuilt all the time.

Note that custom Renderers like this must manage vertex/index buffers themselves (as above), although ‘helper’ classes could easily be added. Renderer is as simple as possible.

I also modified/simplified vertex/index buffers quite a bit. They are now (mostly) statically sized and ‘lockable’. There’s a convience Resize() in there, but they no longer act like mini-stacks, ie: no more AddVertices. Mesh should be pretty much the same though, so as long as you’ve been using tha6t you should be OK. Didn’t have to change meshprims.monkey2 anyway.

[DiffrenzyKeymaster]

Wow! That is so elegant, and it just works!

In my own code, I get a “Memory Access Violation” in Mesh->Method AddVertices( vertices:Vertex3f Ptr,count:Int )

at libc.memcpy( _vertices.Data.Data+first*Vertex3f.Pitch,vertices,count * Vertex3f.Pitch )

should I make a reproducable example, or is this expected?

[Mark SiblyKeymaster]

should I make a reproducable example, or is this expected?

Example please, just had a quick look and can’t see anything obviously wrong.

[DiffrenzyKeymaster]

Probably my code then, something that did not use to bomb, will investigate.

[DiffrenzyKeymaster]

I think I reproduced it:

Monkey

#Import "<std>" #Import "<mojo>" #Import "<mojo3d>" Using std.. Using mojo.. Using mojo3d.. Class MyWindow Extends Window Field _scene:Scene Field _camera:Camera Field _light:Light Field _model:Model Method New() 'get scene ' _scene=Scene.GetCurrent() 'create camera ' _camera=New Camera _camera.Near=.1 _camera.Far=100 _camera.Move( 0,0,-5 ) 'create light ' _light=New Light 'create quad mesh ' Local vertices:=New Vertex3f[4] vertices[0].position=New Vec3f( -1, 1,0 ) vertices[1].position=New Vec3f( 1, 1,0 ) vertices[2].position=New Vec3f( 1,-1,0 ) vertices[3].position=New Vec3f( -1,-1,0 ) Local indices:=New UInt[6] indices[0]=0 indices[1]=1 indices[2]=2 indices[3]=0 indices[4]=2 indices[5]=3 Local mesh:=New Mesh( ) mesh.AddVertices(vertices) mesh.AddTriangles(indices) mesh.AddVertices(vertices) ' <-Error here ' mesh.AddTriangles(indices) mesh.UpdateNormals() 'create model for the mesh ' _model=New Model _model.Mesh=mesh _model.Material=New PbrMaterial( Color.Red ) _model.Material.CullMode=CullMode.None End Method OnRender( canvas:Canvas ) Override RequestRender() _model.RotateY( 1 ) _scene.Render( canvas,_camera ) canvas.DrawText( "Width="+Width+", Height="+Height+", FPS="+App.FPS,0,0 ) End End Function Main() New AppInstance New MyWindow App.Run() End

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#Import "<std>" #Import "<mojo>" #Import "<mojo3d>"   Using std.. Using mojo.. Using mojo3d..   Class MyWindow Extends Window Field _scene:Scene Field _camera:Camera Field _light:Light Field _model:Model Method New() 'get scene ' _scene=Scene.GetCurrent()   'create camera ' _camera=New Camera _camera.Near=.1 _camera.Far=100 _camera.Move( 0,0,-5 ) 'create light ' _light=New Light 'create quad mesh ' Local vertices:=New Vertex3f[4] vertices[0].position=New Vec3f( -1, 1,0 ) vertices[1].position=New Vec3f(  1, 1,0 ) vertices[2].position=New Vec3f(  1,-1,0 ) vertices[3].position=New Vec3f( -1,-1,0 )   Local indices:=New UInt[6] indices[0]=0 indices[1]=1 indices[2]=2 indices[3]=0 indices[4]=2 indices[5]=3 Local mesh:=New Mesh( ) mesh.AddVertices(vertices) mesh.AddTriangles(indices)   mesh.AddVertices(vertices) ' <-Error here ' mesh.AddTriangles(indices) mesh.UpdateNormals() 'create model for the mesh ' _model=New Model _model.Mesh=mesh _model.Material=New PbrMaterial( Color.Red ) _model.Material.CullMode=CullMode.None   End Method OnRender( canvas:Canvas ) Override   RequestRender() _model.RotateY( 1 ) _scene.Render( canvas,_camera )   canvas.DrawText( "Width="+Width+", Height="+Height+", FPS="+App.FPS,0,0 ) End End   Function Main() New AppInstance New MyWindow App.Run() End

[DiffrenzyKeymaster]

.

[Mark SiblyKeymaster]

Fixed in develop branch.

[DiffrenzyKeymaster]

Confimed working.:-)

I’m probably being dim, but I don’t get why you don’t have to multiply by pitch, for the destination address.

If Local first:=_vertices.Length gets the number of elements, and memcpy needs a pointer to the destination address in bytes, your original code seems correct.

[Mark SiblyKeymaster]

I’m probably being dim, but I don’t get why you don’t have to multiply by pitch, for the destination address.

Good question!

Like c/c++, monkey2 pointer addition/subtraction takes the size of the data actually pointed to into account. So ‘p+10’ where p is an int ptr will actually add 40 to p, as ints are 4 bytes long. Ditto p[10] will reference the memory at address ‘p+40’ (using [ ] with pointers is just a special type of pointer addition).

However, libc.memcpy doesn’t know anything about types, it just takes void ptrs and a byte size. Monkey2 ‘fixes’ the pointer params, but not the size so you need to premultiply it by pitch.

It might be an idea to add some ‘typed’ memcpys somewhere, eg:

Monkey

Function t_memcpy:T Ptr( dst:T Ptr,src:T Ptr,count:Int ) libc.memcpy( dst,src,count*libc.sizeof<T>() ) End

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Function t_memcpy:T Ptr( dst:T Ptr,src:T Ptr,count:Int )    libc.memcpy( dst,src,count*libc.sizeof<T>() ) End

This way, you dont’t have to premultiply count by pitch, so the SetVertices code is even simpler.

[DiffrenzyKeymaster]

Thanks, I get it now, this is Pointer arithmetics.

Your ‘typed’ memcpys seems nice!

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