1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
3 * This file is part of the LibreOffice project.
5 * This Source Code Form is subject to the terms of the Mozilla Public
6 * License, v. 2.0. If a copy of the MPL was not distributed with this
7 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
10 attribute vec2 position;
11 attribute vec4 extrusion_vectors;
13 varying float fade_factor; // fade factor for anti-aliasing
15 uniform float line_width;
16 uniform float feather; // width where we fade the line
22 vec2 extrusion_vector = extrusion_vectors.xy;
23 // miter factor to additionally lengthen the distance of vertex (needed for miter)
24 // if 1.0 - miter_factor has no effect
25 float miter_factor = 1.0f / abs(extrusion_vectors.z);
26 // fade factor is always -1.0 or 1.0 -> we transport that info together with length
27 fade_factor = sign(extrusion_vectors.z);
29 float rendered_thickness = (line_width + feather * 2.0) * miter_factor;
31 // lengthen the vertex in direction of the extrusion vector by line width.
32 vec4 position = vec4(position + (extrusion_vector * (rendered_thickness / 2.0) ), 0.0, 1.0);
34 gl_Position = mvp * position;
37 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */