colors - How can i create an image morpher inside a graphics shader? -

image morphing graphic design sfx adapt 1 picture 1 using points decided artist, has match eyes key zones on 1 portrait another, , kinds of algorithms adapt entire picture change 1 another.

i bit similar shader, can load 2 graphics , automatically choose zones of similar colors in same kinds of zone of picture , automatically morph 2 pictures in real time processing. perhaps shader based version logically alot faster @ task? except don't understand how works @ all.

if know, please don't worry complete reply process, great if have save vague background concepts , keywords, how attempt 2d texture morph in graphics shader.

there more morphing methods out there 1 describing based on geometry.

1. morph interpolation

   you have 2 data sets similar properties (for example 2 images both 2d) , interpolate between them parameter. in case of 2d images can use linear interpolation if both images same resolution or trilinear interpolation if not.

   so pick corresponding pixels each images , interpolate actual color parameter t=<0,1>. same resolution this:

   for (y=0;y<img1.height;y++)  (x=0;x<img1.width;x++)   img.pixel[x][y]=(1.0-t)*img1.pixel[x][y] + t*img2.pixel[x][y]; 

   where img1,img2 input images , img ouptput. beware t float need overtype avoid integer rounding problems or use scale t=<0,256> , correct result bit shift right 8 bits or /256 different sizes need bilinear-ly interpolate corresponding (x,y) position in both of source images first.

   all can done in fragment shader. bind img1,img2 texture units 0,1 pick texel them interpolate , output final color. bilinear coordinate interpolation done automatically glsl because texture coordinates normalized <0,1> no matter resolution. in vertex pass texture , vertex coordinates. , in main program side draw single quad covering final image output...

2. morph geometry

   you have 2 polygons (or matching points) , interpolate positions between 2. example this: morph cube coil. suited vector graphics. need have points corespondency , interpolation similar #1.

   for (i=0;i<points;i++)  {  p(i).x=(1.0-t)*p1.x + t*p2.x  p(i).y=(1.0-t)*p1.y + t*p2.y  } 

   where p1(i),p2(i) i-th point each input geometry set , p(i) point final result...

   to enhance visual appearance linear interpolation exchanged specific trajectory (like bezier curves) morph more cool. example see

   • path generation non-intersecting disc movement on plane

   to acomplish need use geometry shader (or maybe tesselation shader). need pass both polygons single primitive, geometry shader should interpolate actual polygon , pass vertex shader.

3. morph particle swarms

   in case find corresponding pixels in source images matching colors. handle each pixel particle , create path position in img1 img2 parameter t. s same #2 instead polygon areas got points. particle has color,position interpolate both ... because there slim chance exact color matches , count ... (histograms same) in-probable.

4. hybrid morphing

   it combination of #1,#2,#3

i sure there more methods morphing these ones know of. morphing can done not in spatial domain...