/* * st-scroll-view-fade.glsl: Edge fade effect for StScrollView * * Copyright 2010 Intel Corporation. * Copyright 2011 Adel Gadllah * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU Lesser General Public License, * version 2.1, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT ANY * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for * more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see . */ uniform sampler2D tex; uniform float height; uniform float width; uniform float offset_bottom; uniform float offset_top; uniform float offset_right; uniform float offset_left; /* * Used to pass the fade area to the shader * * [0][0] = x1 * [0][1] = y1 * [1][0] = x2 * [1][1] = y2 * */ uniform mat2 fade_area; void main () { cogl_color_out = cogl_color_in * texture2D (tex, vec2 (cogl_tex_coord_in[0].xy)); float y = height * cogl_tex_coord_in[0].y; float x = width * cogl_tex_coord_in[0].x; if (x < fade_area[0][0] || x > fade_area[1][0] || y < fade_area[0][1] || y > fade_area[1][1]) return; float ratio = 1.0; float fade_bottom_start = fade_area[1][1] - offset_bottom; float fade_right_start = fade_area[1][0] - offset_right; float ratio_top = y / offset_top; float ratio_bottom = (fade_area[1][1] - y)/(fade_area[1][1] - fade_bottom_start); float ratio_left = x / offset_left; float ratio_right = (fade_area[1][0] - x)/(fade_area[1][0] - fade_right_start); bool in_scroll_area = fade_area[0][0] <= x && fade_area[1][0] >= x; bool fade_top = y < offset_top; bool fade_bottom = y > fade_bottom_start; bool fade_left = x < offset_left; bool fade_right = x > fade_right_start; if (fade_top) { ratio *= ratio_top; } if (fade_bottom) { ratio *= ratio_bottom; } if (fade_left) { ratio *= ratio_left; } if (fade_right) { ratio *= ratio_right; } cogl_color_out *= ratio; }