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d333eb6b
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Leszek Koltunski
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//////////////////////////////////////////////////////////////////////////////////////////////
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// Copyright 2016 Leszek Koltunski //
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// //
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// This file is part of Distorted. //
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// //
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// Distorted is free software: you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation, either version 2 of the License, or //
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// (at your option) any later version. //
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// //
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// Distorted is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with Distorted. If not, see <http://www.gnu.org/licenses/>. //
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//////////////////////////////////////////////////////////////////////////////////////////////
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341151fc
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Leszek Koltunski
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precision highp float;
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precision highp int;
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Leszek Koltunski
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in vec3 a_Position; // Per-vertex position.
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in vec3 a_Normal; // Per-vertex normal vector.
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Leszek Koltunski
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in vec3 a_Inflate; // This vector describes the direction this vertex needs to go when we 'inflate' the whole mesh.
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// If the mesh is locally smooth, this is equal to the normal vector. Otherwise (on sharp edges) - no.
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in vec2 a_TexCoordinate; // Per-vertex texture coordinate.
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out vec3 v_Position; //
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out vec3 v_endPosition; // for Transform Feedback only
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Leszek Koltunski
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out vec3 v_Normal; //
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out vec2 v_TexCoordinate; //
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uniform vec3 u_objD; // half of object width x half of object height X half the depth;
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// point (0,0,0) is the center of the object
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uniform mat4 u_MVPMatrix; // the combined model/view/projection matrix.
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uniform mat4 u_MVMatrix; // the combined model/view matrix.
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#if NUM_VERTEX>0
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uniform int vNumEffects; // total number of vertex effects
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uniform int vName[NUM_VERTEX]; // their names.
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uniform vec4 vUniforms[3*NUM_VERTEX];// i-th effect is 3 consecutive vec4's: [3*i], [3*i+1], [3*i+2].
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// The first vec4 is the Interpolated values,
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// next is half cache half Center, the third - the Region.
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//////////////////////////////////////////////////////////////////////////////////////////////
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// HELPER FUNCTIONS
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//////////////////////////////////////////////////////////////////////////////////////////////
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// The trick below is the if-less version of the
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//
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// t = dx<0.0 ? (u_objD.x-v.x) / (u_objD.x-ux) : (u_objD.x+v.x) / (u_objD.x+ux);
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// h = dy<0.0 ? (u_objD.y-v.y) / (u_objD.y-uy) : (u_objD.y+v.y) / (u_objD.y+uy);
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// d = min(t,h);
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//
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// float d = min(-ps.x/(sign(ps.x)*u_objD.x+p.x),-ps.y/(sign(ps.y)*u_objD.y+p.y))+1.0;
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//
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// We still have to avoid division by 0 when p.x = +- u_objD.x or p.y = +- u_objD.y (i.e on the edge of the Object)
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// We do that by first multiplying the above 'float d' with sign(denominator1*denominator2)^2.
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//
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//////////////////////////////////////////////////////////////////////////////////////////////
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// return degree of the point as defined by the bitmap rectangle
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float degree_bitmap(in vec2 S, in vec2 PS)
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{
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vec2 A = sign(PS)*u_objD.xy + S;
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vec2 signA = sign(A); //
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vec2 signA_SQ = signA*signA; // div = PS/A if A!=0, 0 otherwise.
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vec2 div = signA_SQ*PS/(A-(vec2(1,1)-signA_SQ));//
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return 1.0-max(div.x,div.y);
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Leszek Koltunski
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}
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//////////////////////////////////////////////////////////////////////////////////////////////
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Leszek Koltunski
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// Return degree of the point as defined by the Region. Currently only supports circular regions.
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//
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// Let us first introduce some notation.
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// Let 'PS' be the vector from point P (the current vertex) to point S (the center of the effect).
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// Let region.xy be the vector from point S to point O (the center point of the region circle)
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// Let region.z be the radius of the region circle.
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73af5285
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Leszek Koltunski
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// (This all should work regardless if S is inside or outside of the circle).
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//
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// Then, the degree of a point with respect to a given (circular!) Region is defined by:
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//
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// If P is outside the circle, return 0.
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// Otherwise, let X be the point where the halfline SP meets the region circle - then return |PX|/||SX|,
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// aka the 'degree' of point P.
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//
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// We solve the triangle OPX.
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Leszek Koltunski
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// We know the lengths |PO|, |OX| and the angle OPX, because cos(OPX) = cos(180-OPS) = -cos(OPS) = -PS*PO/(|PS|*|PO|)
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// then from the law of cosines PX^2 + PO^2 - 2*PX*PO*cos(OPX) = OX^2 so PX = -a + sqrt(a^2 + OX^2 - PO^2)
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// where a = PS*PO/|PS| but we are really looking for d = |PX|/(|PX|+|PS|) = 1/(1+ (|PS|/|PX|) ) and
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// |PX|/|PS| = -b + sqrt(b^2 + (OX^2-PO^2)/PS^2) where b=PS*PO/|PS|^2 which can be computed with only one sqrt.
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Leszek Koltunski
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float degree_region(in vec4 region, in vec2 PS)
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Leszek Koltunski
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{
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vec2 PO = PS + region.xy;
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float D = region.z*region.z-dot(PO,PO); // D = |OX|^2 - |PO|^2
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Leszek Koltunski
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if( D<=0.0 ) return 0.0;
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float ps_sq = dot(PS,PS);
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float one_over_ps_sq = 1.0/(ps_sq-(sign(ps_sq)-1.0)); // return 1.0 if ps_sq = 0.0
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// Important: if we want to write
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// b = 1/a if a!=0, b=1 otherwise
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// we need to write that as
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// b = 1 / ( a-(sign(a)-1) )
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// [ and NOT 1 / ( a + 1 - sign(a) ) ]
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// because the latter, if 0<a<2^-24,
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// will suffer from round-off error and in this case
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// a + 1.0 = 1.0 !! so 1 / (a+1-sign(a)) = 1/0 !
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float DOT = dot(PS,PO)*one_over_ps_sq;
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return 1.0 / (1.0 + 1.0/(sqrt(DOT*DOT+D*one_over_ps_sq)-DOT));
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}
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//////////////////////////////////////////////////////////////////////////////////////////////
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// return min(degree_bitmap,degree_region). Just like degree_region, currently only supports circles.
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float degree(in vec4 region, in vec2 S, in vec2 PS)
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{
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vec2 PO = PS + region.xy;
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float D = region.z*region.z-dot(PO,PO); // D = |OX|^2 - |PO|^2
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if( D<=0.0 ) return 0.0;
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vec2 A = sign(PS)*u_objD.xy + S;
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vec2 signA = sign(A);
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vec2 signA_SQ = signA*signA;
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vec2 div = signA_SQ*PS/(A-(vec2(1,1)-signA_SQ));
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float E = 1.0-max(div.x,div.y);
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float ps_sq = dot(PS,PS);
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float one_over_ps_sq = 1.0/(ps_sq-(sign(ps_sq)-1.0)); // return 1.0 if ps_sq = 0.0
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float DOT = dot(PS,PO)*one_over_ps_sq;
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return min(1.0/(1.0 + 1.0/(sqrt(DOT*DOT+D*one_over_ps_sq)-DOT)),E);
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}
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leszek
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#endif // NUM_VERTEX>0
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6a06a912
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Leszek Koltunski
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//////////////////////////////////////////////////////////////////////////////////////////////
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void main()
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{
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vec3 v = 2.0*u_objD*a_Position;
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vec3 n = a_Normal;
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#if NUM_VERTEX>0
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leszek
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int effect=0;
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for(int i=0; i<vNumEffects; i++)
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{
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// ENABLED EFFECTS WILL BE INSERTED HERE
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effect+=3;
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}
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#endif
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leszek
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v_Position = v;
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v_endPosition = v + (0.3*u_objD.x)*n;
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v_TexCoordinate = a_TexCoordinate;
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v_Normal = normalize(vec3(u_MVMatrix*vec4(n,0.0)));
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gl_Position = u_MVPMatrix*vec4(v,1.0);
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d333eb6b
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}
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