commit cd174a6431cef4d9d78f720bc26112df1d4be36e Author: Leszek Koltunski Date: Tue Jun 28 14:01:10 2016 +0100 Make the 'deform' effect continuous when 'center' point passes through (0,0) i.e. middle of the Object. diff --git a/src/main/res/raw/main_vertex_shader.glsl b/src/main/res/raw/main_vertex_shader.glsl index 9797719..90d46ac 100644 --- a/src/main/res/raw/main_vertex_shader.glsl +++ b/src/main/res/raw/main_vertex_shader.glsl @@ -146,13 +146,13 @@ void restrict(inout float v) ////////////////////////////////////////////////////////////////////////////////////////////// // DEFORM EFFECT // -// Deform the whole shape of the bitmap by force V +// Deform the whole shape of the Object by force V // -// If the point of application (Sx,Sy) is on the edge of the bitmap, then: +// If the point of application (Sx,Sy) is on the edge of the Object, then: // a) ignore Vz -// b) change shape of the whole bitmap in the following way: -// Suppose the upper-left corner of the bitmap rectangle is point L, upper-right - R, force vector V is applied to point M on the upper edge, -// length of the bitmap = w, height = h, |LM| = Wl, |MR| = Wr, force vector V=(Vx,Vy). Also let H = h/(h+Vy) +// b) change shape of the whole Object in the following way: +// Suppose the upper-left corner of the Object rectangle is point L, upper-right - R, force vector V is applied to point M on the upper edge, +// width of the Object = w, height = h, |LM| = Wl, |MR| = Wr, force vector V=(Vx,Vy). Also let H = h/(h+Vy) // // Let now L' and R' be points such that vec(LL') = Wr/w * vec(V) and vec(RR') = Wl/w * vec(V) // now let Vl be a point on the line segment L --> M+vec(V) such that Vl(y) = L'(y) @@ -165,7 +165,7 @@ void restrict(inout float v) // vec(Fl) = (Wr/w) * [ (Vx+Wl)-Wl*H, Vy ] = (Wr/w) * [ Wl*Vy / (h+Vy) + Vx, Vy ] // vec(Fr) = (Wl/w) * [ (Vx-Wr)+Wr*H, Vy ] = (Wl/w) * [-Wr*Vy / (h+Vy) + Vx, Vy ] // -// Lets now denote M+vec(v) = M'. The line segment LMR gets distorted to the curve Fl-M'-Fr. Let's now arbitrarilly decide that: +// Lets now denote M+vec(V) = M'. The line segment LMR gets distorted to the curve Fl-M'-Fr. Let's now arbitrarilly decide that: // a) at point Fl the curve has to be parallel to line LM' // b) at point M' - to line LR // c) at point Fr - to line M'R @@ -188,29 +188,30 @@ void restrict(inout float v) // If we are dragging the top edge: // // Now point (x,u_objD.x) on the top edge will move by vector (X(t),Y(t)) where those functions are given by (*) and -// t = x < dSx ? (u_objD.x+x)/(u_objD.x+dSx) : (u_objD.x-x)/(u_objD.x-dSx) +// t = x < dSx ? (u_objD.x+x)/(u_objD.x+dSx) : (u_objD.x-x)/(u_objD.x-dSx) (this is 'vec2 time' below in the code) // Any point (x,y) will move by vector (a*X(t),a*Y(t)) where a is (y+u_objD.y)/(2*u_objD.y) void deform(in int effect, inout vec4 v) { - vec2 p = vUniforms[effect+2].yz; - vec2 w = vUniforms[effect].xy; // w = vec(MM') + vec2 center = vUniforms[effect+2].yz; + vec2 force = vUniforms[effect].xy; // force = vec(MM') vec2 vert_vec, horz_vec; - vec2 signXY = sign(p-v.xy); - vec2 time = (u_objD.xy+signXY*v.xy)/(u_objD.xy+signXY*p); - vec2 factorV = vec2(0.5,0.5) + sign(p)*v.xy/(4.0*u_objD.xy); - vec2 factorD = (u_objD.xy-signXY*p)/(2.0*u_objD.xy); - vec2 vert_d = factorD.x*w; - vec2 horz_d = factorD.y*w; - vec2 corr = 0.33 / ( 1.0 + (4.0*u_objD.x*u_objD.x)/dot(w,w) ) * (p+w+signXY*u_objD.xy); // .x = the vector tangent to X(t) at Fl = 0.3*vec(LM') (or vec(RM') if signXY.x=-1). - // .y = the vector tangent to X(t) at Fb = 0.3*vec(BM') (or vec(TM') if signXY.y=-1) - // the scalar: make the length of the speed vectors at Fl and Fr be 0 when force vector 'w' is zero - vert_vec.x = ( w.x-vert_d.x-corr.x )*time.x*time.x + corr.x*time.x + vert_d.x; - horz_vec.y = (-w.y+horz_d.y+corr.y )*time.y*time.y - corr.y*time.y - horz_d.y; - vert_vec.y = (-3.0*vert_d.y+2.0*w.y )*time.x*time.x*time.x + (-3.0*w.y+5.0*vert_d.y )*time.x*time.x - vert_d.y*time.x - vert_d.y; - horz_vec.x = ( 3.0*horz_d.x-2.0*w.x )*time.y*time.y*time.y + ( 3.0*w.x-5.0*horz_d.x )*time.y*time.y + horz_d.x*time.y + horz_d.x; + vec2 signXY = sign(center-v.xy); + vec2 time = (u_objD.xy+signXY*v.xy)/(u_objD.xy+signXY*center); + vec2 factorV = vec2(0.5,0.5) + (center*v.xy)/(4.0*u_objD.xy*u_objD.xy); + vec2 factorD = (u_objD.xy-signXY*center)/(2.0*u_objD.xy); + vec2 vert_d = factorD.x*force; + vec2 horz_d = factorD.y*force; + float dot = dot(force,force); + vec2 corr = 0.33 * (center+force+signXY*u_objD.xy) * dot / ( dot + (4.0*u_objD.x*u_objD.x) ); // .x = the vector tangent to X(t) at Fl = 0.3*vec(LM') (or vec(RM') if signXY.x=-1). + // .y = the vector tangent to X(t) at Fb = 0.3*vec(BM') (or vec(TM') if signXY.y=-1) + // the scalar: make the length of the speed vectors at Fl and Fr be 0 when force vector 'force' is zero + vert_vec.x = ( force.x-vert_d.x-corr.x )*time.x*time.x + corr.x*time.x + vert_d.x; + horz_vec.y = (-force.y+horz_d.y+corr.y )*time.y*time.y - corr.y*time.y - horz_d.y; + vert_vec.y = (-3.0*vert_d.y+2.0*force.y )*time.x*time.x*time.x + (-3.0*force.y+5.0*vert_d.y )*time.x*time.x - vert_d.y*time.x - vert_d.y; + horz_vec.x = ( 3.0*horz_d.x-2.0*force.x )*time.y*time.y*time.y + ( 3.0*force.x-5.0*horz_d.x )*time.y*time.y + horz_d.x*time.y + horz_d.x; - v.xy += (factorV.y*vert_vec + factorV.x*horz_vec); + v.xy += (factorV.y*vert_vec + factorV.x*horz_vec); } //////////////////////////////////////////////////////////////////////////////////////////////