5c439f4e9c
This doesn't (or shouldn't) change the visual appearance of the fade effect, but does do all the testing math inside the shader, rather than on the CPU. This will make fading the offset much easier in the future. https://bugzilla.gnome.org/show_bug.cgi?id=689249
82 lines
2.2 KiB
GLSL
82 lines
2.2 KiB
GLSL
/*
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* st-scroll-view-fade.glsl: Edge fade effect for StScrollView
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*
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* Copyright 2010 Intel Corporation.
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* Copyright 2011 Adel Gadllah
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU Lesser General Public License,
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* version 2.1, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
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* more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#version 120
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uniform sampler2D tex;
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uniform float height;
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uniform float width;
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uniform float vfade_offset;
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uniform float hfade_offset;
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uniform float vvalue;
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uniform float hvalue;
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/*
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* Used to pass the fade area to the shader
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*
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* [0][0] = x1
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* [0][1] = y1
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* [1][0] = x2
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* [1][1] = y2
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*
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*/
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uniform mat2 fade_area;
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void main ()
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{
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cogl_color_out = cogl_color_in * texture2D (tex, vec2 (cogl_tex_coord_in[0].xy));
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float y = height * cogl_tex_coord_in[0].y;
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float x = width * cogl_tex_coord_in[0].x;
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if (x < fade_area[0][0] || x > fade_area[1][0] ||
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y < fade_area[0][1] || y > fade_area[1][1])
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return;
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float ratio = 1.0;
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float fade_bottom_start = fade_area[1][1] - vfade_offset;
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float fade_right_start = fade_area[1][0] - hfade_offset;
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float ratio_top = y / vfade_offset;
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float ratio_bottom = (fade_area[1][1] - y)/(fade_area[1][1] - fade_bottom_start);
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float ratio_left = x / hfade_offset;
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float ratio_right = (fade_area[1][0] - x)/(fade_area[1][0] - fade_right_start);
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bool fade_top = y < vfade_offset && vvalue > 0;
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bool fade_bottom = y > fade_bottom_start && vvalue < 1;
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bool fade_left = x < hfade_offset && hvalue > 0;
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bool fade_right = x > fade_right_start && hvalue < 1;
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if (fade_top) {
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ratio *= ratio_top;
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}
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if (fade_bottom) {
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ratio *= ratio_bottom;
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}
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if (fade_left) {
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ratio *= ratio_left;
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}
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if (fade_right) {
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ratio *= ratio_right;
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}
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cogl_color_out *= ratio;
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}
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