Morphing in MoleHill using a vertex shader

Question

Using the Molehill with Flash I wish to create a vertiex shader, to have one mesh transform into another, I have seen that it is possible with Flare, However I am unsure if that was using Stage3D, Can anyone give me any pointers in the use of shaders in AGAL as to how this might be done. Thanks

Answer 1

(maybe too late)

a morphing is "simply" a linear interpolation between 2 sets of positions.

assuming you have a first vertexBuffer VA0 representing the origins and a second vertexbuffer VA1 representing your destinations. you can store them in temporary registers:

"mov vt0 va0                \n" +//temp var, will hold the result
"mov vt1 va0                \n" +//start position
"mov vt2 va1                \n" +//destination

then you'll need a T value that you can pass as a constant like this:

context.setProgramConstantsFromVector( Context3DProgramType.VERTEX, id, constant );

if you pass something like

Vector.<Number>([ T, 0,0, 1 ])

with 0<=T<=1 as the constant and put it at id 0, the following code will transform (linearly inpterpolate) the output positions from the starting position to the end position.

//lerp
"sub vt0 vt2 vt1            \n" +
"mul vt0 vt0 vc0.x          \n" +
"add vt0 vt0 va1            \n" +

then you need to project VT0 to get the correct output.

Answer 2

The next version of pixel bender should support creating both 3d vertex and fragment shaders. A preview release should be available here