1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
/*
* This program source code file is part of KICAD, a free EDA CAD application.
*
* Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
* Copyright (C) 2012 Kicad Developers, see change_log.txt for contributors.
*
* Geometry shader
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#version 120
#extension GL_EXT_geometry_shader4: enable
#extension GL_EXT_gpu_shader4: enable
uniform float viewPortX2;
uniform float viewPortY2;
varying float dist;
void main()
{
// Compute the transformed start and end points
vec2 startPoint = gl_PositionIn[0].xy;
vec2 endPoint = gl_PositionIn[1].xy;
float lineWidth = gl_PositionIn[1].z;
// Compute vector start -> end
vec2 startEndVector = endPoint.xy - startPoint.xy;
float lineLength = distance( startPoint, endPoint );
float scale = 0.0;
if( lineLength > 0.0 )
{
scale = 0.5 * lineWidth / lineLength;
}
else
{
scale = 0.0;
}
// Compute the edge points of the line
vec2 perpendicularVector = scale * vec2( -startEndVector.y, startEndVector.x );
vec2 point1 = startPoint + perpendicularVector;
vec2 point2 = startPoint - perpendicularVector;
vec2 point3 = endPoint + perpendicularVector;
vec2 point4 = endPoint - perpendicularVector;
vec4 point1T = gl_ModelViewProjectionMatrix * vec4( point1, gl_PositionIn[0].zw );
vec4 point2T = gl_ModelViewProjectionMatrix * vec4( point2, gl_PositionIn[0].zw );
vec4 point3T = gl_ModelViewProjectionMatrix * vec4( point3, gl_PositionIn[0].zw );
vec4 point4T = gl_ModelViewProjectionMatrix * vec4( point4, gl_PositionIn[0].zw );
// Construct the quad for the middle
gl_FrontColor = gl_FrontColorIn[0];
dist = 0;
gl_Position = point1T;
EmitVertex();
dist = 0;
gl_Position = point2T;
EmitVertex();
dist = 0;
gl_Position = point3T;
EmitVertex();
dist = 0;
gl_Position = point4T;
EmitVertex();
EndPrimitive();
// Compute the perpendicular vector with 1 pixel width
vec2 v = point1T.xy - point3T.xy;
vec4 onePix = 0.5 * vec4( -v.y, v.x, 0, 0 );
onePix *= 1.0 / sqrt( dot( onePix, onePix ) );
onePix.x *= 1.0 / viewPortX2;
onePix.y *= 1.0 / viewPortY2;
gl_FrontColor = gl_FrontColorIn[0];
dist = 1;
gl_Position = point1T + onePix;
EmitVertex();
dist = 1;
gl_Position = point3T + onePix;
EmitVertex();
dist = 0;
gl_Position = point1T;
EmitVertex();
dist = 0;
gl_Position = point3T;
EmitVertex();
EndPrimitive();
dist = 1;
gl_Position = point2T - onePix;
EmitVertex();
dist = 1;
gl_Position = point4T - onePix;
EmitVertex();
dist = 0;
gl_Position = point2T;
EmitVertex();
dist = 0;
gl_Position = point4T;
EmitVertex();
EndPrimitive();
}