#version 450 core
struct DataS { vec2 pos; vec2 v1; vec2 v2; vec2 rad; };
layout (std430, binding = 9) readonly buffer Data { DataS data[]; };
layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
out vec2 texPos;
out vec2 distmask;
out vec2 pinch;
const int ks[6] =   
    {0,1,2          //  2--3
    ,2,1,3          //  |  |
    };              //  0--1
const vec2 cs[4] =
    { vec2 (-1,-1)
    , vec2 ( 1,-1)
    , vec2 (-1, 1)
    , vec2 ( 1, 1)
    };
void main()
{
  int k = ks[gl_VertexID];
  vec4 off = (theMat * vec4(data[gl_VertexID/6].pos, 0,1));
  vec2 r1 = (theMat * vec4(data[gl_VertexID/6].v1, 0,1)).xy
            - (theMat * vec4(0,0,0,1)).xy;
  vec2 r2 = (theMat * vec4(data[gl_VertexID/6].v2, 0,1)).xy
            - (theMat * vec4(0,0, 0,1)).xy;
  pinch = 
        (theMat * vec4(data[gl_VertexID/6].rad, 0,1)).xy
        - (theMat * vec4(0,0, 0,1)).xy;
//  mat2 distT = mat2(-1/r1.x, -1/r2.x
//                   ,1/r1.y, -1/r2.y
//                   );
//  mat2 distT = mat2(2, 0
//                   ,-1/sqrt(2), 1/sqrt(2)
//                   );
//  mat2 distT = mat2(1/r1.x, 2*sqrt(2)
//                    ,1/r1.y, 2*sqrt(2)
//                   );
  mat2 distT = inverse (mat2(r1,r2));
//  mat2 distT = mat2(1/r1.x, 1/r2.x
//                   ,1/r1.y, 1/r2.y
//                   );
  //distmask = (cs[k] - off.xy)/r;
  distmask = distT * (cs[k] - off.xy);
  texPos = 0.5 * (cs[k]+vec2(1,1));
  gl_Position = vec4 (cs[k],0,1);
}