59 lines
1.5 KiB
GLSL
59 lines
1.5 KiB
GLSL
#version 450 core
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struct DataS { vec2 pos; vec2 v1; vec2 v2; vec2 t1; vec2 t2; vec2 t3; };
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layout (std430, binding = 9) readonly buffer Data { DataS data[]; };
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layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
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out vec2 texPos;
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out vec2 distmask[2];
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out vec2 pinch[2];
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const int ks[6] =
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{0,1,2 // 2--3
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,2,1,3 // | |
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}; // 0--1
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const vec2 cs[4] =
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{ vec2 (-1,-1)
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, vec2 ( 1,-1)
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, vec2 (-1, 1)
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, vec2 ( 1, 1)
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};
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vec2 f (vec2 p) // transforms a vector from "world" into "screen" space
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{ return (theMat * vec4(p,0,1) - theMat * vec4(0,0,0,1)).xy; }
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vec2 g (vec2 p)
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{ return normalize(p); }
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vec2 ncToTex (vec2 p) {return 0.5 * (p + 1);}
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mat4 toTransMat (vec2 p)
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{ return mat4
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( 1, 0, 0 ,0
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, 0, 1, 0 ,0
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, 0, 0, 1 ,0
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,p.x,p.y, 0 ,1
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) ;
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}
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void main()
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{
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int k = ks[gl_VertexID];
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for(int i = 0; i < 2; ++i)
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{
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vec4 off = theMat * vec4(data[i + gl_VertexID/6].pos, 0,1);
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DataS thedata = data[i + gl_VertexID/6];
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vec2 r1 = f(thedata.v1);
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vec2 r2 = f(thedata.v2);
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mat2 distT = inverse (mat2(r1,r2));
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distmask[i] = (distT * (cs[k] - off.xy));
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vec4 pinchx = theMat
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* toTransMat(thedata.t3)
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* toTransMat(thedata.pos)
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* mat4
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(thedata.t1 , 0, 0
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,thedata.t2 , 0, 0
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, 0, 0 , 0, 0
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, 0, 0 , 0, 1
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)
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* inverse(toTransMat(thedata.pos))
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* inverse(theMat)
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* (vec4(cs[k],0,1));
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pinch[i] = ncToTex(pinchx.xy) - ncToTex(cs[k]);
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}
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texPos = ncToTex(cs[k]);
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gl_Position = vec4 (cs[k],0,1);
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}
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