45fc7ec01f
Returing from main() makes llvmpipe unhappy (produces black output color), so rework the logic to avoid the return. https://bugzilla.gnome.org/show_bug.cgi?id=695607
88 lines
2.8 KiB
GLSL
88 lines
2.8 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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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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/*
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* Scale from [0.0, 1.0] to [1.0, 1.0]. Do this by
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* changing it to scaling [1.0, 0.0] to [0.0, 0.0]
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* and then transforming the end result.
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*/
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#define FADE(gradient, factor) (1.0 - (1.0 - gradient) * factor)
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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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/*
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* We cannot just return here due to a bug in llvmpipe see:
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* https://bugzilla.freedesktop.org/show_bug.cgi?id=62357
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*/
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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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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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bool fade_top = y < vfade_offset && vvalue > 0.0;
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bool fade_bottom = y > fade_bottom_start && vvalue < 1.0;
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bool fade_left = x < hfade_offset && hvalue > 0.0;
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bool fade_right = x > fade_right_start && hvalue < 1.0;
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float vfade_scale = height / vfade_offset;
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if (fade_top) {
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ratio *= FADE((y / vfade_offset), min(sqrt(vvalue) * vfade_scale, 1.0));
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}
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if (fade_bottom) {
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ratio *= FADE((fade_area[1][1] - y)/(fade_area[1][1] - fade_bottom_start), min(sqrt(1.0 - vvalue) * vfade_scale, 1.0));
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}
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float hfade_scale = width / hfade_offset;
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if (fade_left) {
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ratio *= FADE(x / hfade_offset, min(sqrt(hvalue) * hfade_scale, 1.0));
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}
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if (fade_right) {
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ratio *= FADE((fade_area[1][0] - x)/(fade_area[1][0] - fade_right_start), min(sqrt(1.0 - hvalue) * hfade_scale, 1.0));
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}
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cogl_color_out *= ratio;
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}
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}
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