VERTEX_SHADER = """ const float PI = 3.14159265358979323846264; const float THETA = 15.0 * 3.14159265358979323846264/180.0; // Cross product of v1 and v2 float cross(in vec2 v1, in vec2 v2) { return v1.x*v2.y - v1.y*v2.x; } // Returns distance of v3 to line v1-v2 float signed_distance(in vec2 v1, in vec2 v2, in vec2 v3) { return cross(v2-v1,v1-v3) / length(v2-v1); } // Rotate v around origin void rotate( in vec2 v, in float alpha, out vec2 result ) { float c = cos(alpha); float s = sin(alpha); result = vec2( c*v.x - s*v.y, s*v.x + c*v.y ); } vec2 transform_vector(vec2 x, vec2 base) { vec4 o = $transform(vec4(base, 0, 1)); return ($transform(vec4(base+x, 0, 1)) - o).xy; } // Uniforms //uniform mat4 u_matrix; //uniform mat4 u_view; attribute vec4 color; // uniform vec2 u_scale; // uniform vec2 tr_scale; uniform float linewidth; uniform float antialias; uniform vec2 linecaps; uniform float linejoin; uniform float miter_limit; attribute float alength; uniform float dash_phase; uniform float dash_period; uniform float dash_index; uniform vec2 dash_caps; uniform float closed; // Attributes attribute vec2 a_position; // position of each vertex attribute vec4 a_tangents; // vector pointing from one vertex to the next attribute vec2 a_segment; // distance along path attribute vec2 a_angles; attribute vec2 a_texcoord; // Varying varying vec4 v_color; varying vec2 v_segment; varying vec2 v_angles; varying vec2 v_linecaps; varying vec2 v_texcoord; varying vec2 v_miter; varying float v_miter_limit; varying float v_length; varying float v_linejoin; varying float v_linewidth; varying float v_antialias; varying float v_dash_phase; varying float v_dash_period; varying float v_dash_index; varying vec2 v_dash_caps; varying float v_closed; void main() { v_color = color; v_linewidth = linewidth; v_antialias = antialias; v_linecaps = linecaps; v_linejoin = linejoin; v_miter_limit = miter_limit; v_length = alength; v_dash_phase = dash_phase; v_dash_period = dash_period; v_dash_index = dash_index; v_dash_caps = dash_caps; v_closed = closed; bool closed = (v_closed > 0.0); // Attributes to varyings v_angles = a_angles; //v_segment = a_segment * u_scale.x * tr_scale.x; // TODO: proper scaling //v_length = v_length * u_scale * tr_scale; // TODO: proper scaling v_segment = a_segment; // Thickness below 1 pixel are represented using a 1 pixel thickness // and a modified alpha v_color.a = min(v_linewidth, v_color.a); v_linewidth = max(v_linewidth, 1.0); // If color is fully transparent we just will discard the fragment anyway if( v_color.a <= 0.0 ) { gl_Position = vec4(0.0,0.0,0.0,1.0); return; } // This is the actual half width of the line // TODO: take care of logical - physical pixel difference here. float w = ceil(1.25*v_antialias+v_linewidth)/2.0; //vec2 position = $transform(vec4(a_position,0.,1.)).xy*u_scale; vec2 position = $transform(vec4(a_position,0.,1.)).xy; // At this point, position must be in _doc_ coordinates because the line // width will be added to it. //vec2 t1 = normalize(tr_scale*a_tangents.xy); //vec2 t2 = normalize(tr_scale*a_tangents.zw); vec2 t1 = normalize(transform_vector(a_tangents.xy, a_position)); vec2 t2 = normalize(transform_vector(a_tangents.zw, a_position)); float u = a_texcoord.x; float v = a_texcoord.y; vec2 o1 = vec2( +t1.y, -t1.x); vec2 o2 = vec2( +t2.y, -t2.x); // This is a join // ---------------------------------------------------------------- if( t1 != t2 ) { float angle = atan (t1.x*t2.y-t1.y*t2.x, t1.x*t2.x+t1.y*t2.y); vec2 t = normalize(t1+t2); vec2 o = vec2( + t.y, - t.x); if ( v_dash_index > 0.0 ) { // Broken angle // ---------------------------------------------------------------- if( (abs(angle) > THETA) ) { position += v * w * o / cos(angle/2.0); float s = sign(angle); if( angle < 0.0 ) { if( u == +1.0 ) { u = v_segment.y + v * w * tan(angle/2.0); if( v == 1.0 ) { position -= 2.0 * w * t1 / sin(angle); u -= 2.0 * w / sin(angle); } } else { u = v_segment.x - v * w * tan(angle/2.0); if( v == 1.0 ) { position += 2.0 * w * t2 / sin(angle); u += 2.0*w / sin(angle); } } } else { if( u == +1.0 ) { u = v_segment.y + v * w * tan(angle/2.0); if( v == -1.0 ) { position += 2.0 * w * t1 / sin(angle); u += 2.0 * w / sin(angle); } } else { u = v_segment.x - v * w * tan(angle/2.0); if( v == -1.0 ) { position -= 2.0 * w * t2 / sin(angle); u -= 2.0*w / sin(angle); } } } // Continuous angle // ------------------------------------------------------------ } else { position += v * w * o / cos(angle/2.0); if( u == +1.0 ) u = v_segment.y; else u = v_segment.x; } } // Solid line // -------------------------------------------------------------------- else { position.xy += v * w * o / cos(angle/2.0); if( angle < 0.0 ) { if( u == +1.0 ) { u = v_segment.y + v * w * tan(angle/2.0); } else { u = v_segment.x - v * w * tan(angle/2.0); } } else { if( u == +1.0 ) { u = v_segment.y + v * w * tan(angle/2.0); } else { u = v_segment.x - v * w * tan(angle/2.0); } } } // This is a line start or end (t1 == t2) // ------------------------------------------------------------------------ } else { position += v * w * o1; if( u == -1.0 ) { u = v_segment.x - w; position -= w * t1; } else { u = v_segment.y + w; position += w * t2; } } // Miter distance // ------------------------------------------------------------------------ vec2 t; //vec2 curr = $transform(vec4(a_position,0.,1.)).xy*u_scale; vec2 curr = $transform(vec4(a_position,0.,1.)).xy; if( a_texcoord.x < 0.0 ) { vec2 next = curr + t2*(v_segment.y-v_segment.x); rotate( t1, +a_angles.x/2.0, t); v_miter.x = signed_distance(curr, curr+t, position); rotate( t2, +a_angles.y/2.0, t); v_miter.y = signed_distance(next, next+t, position); } else { vec2 prev = curr - t1*(v_segment.y-v_segment.x); rotate( t1, -a_angles.x/2.0,t); v_miter.x = signed_distance(prev, prev+t, position); rotate( t2, -a_angles.y/2.0,t); v_miter.y = signed_distance(curr, curr+t, position); } if (!closed && v_segment.x <= 0.0) { v_miter.x = 1e10; } if (!closed && v_segment.y >= v_length) { v_miter.y = 1e10; } v_texcoord = vec2( u, v*w ); gl_Position = $px_ndc_transform($doc_px_transform(vec4(position, 0.0, 1.0))); } """