1 files changed, 74 insertions, 0 deletions
diff --git a/src/st/st-scroll-view-fade.glsl b/src/st/st-scroll-view-fade.glsl
new file mode 100644
index 0000000..9180aa1
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+++ b/src/st/st-scroll-view-fade.glsl
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+/*
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+uniform sampler2D tex;
+uniform float height;
+uniform float width;
+uniform float vfade_offset;
+uniform float hfade_offset;
+uniform bool  fade_edges_top;
+uniform bool  fade_edges_right;
+uniform bool  fade_edges_bottom;
+uniform bool  fade_edges_left;
+
+uniform vec2 fade_area_topleft;
+uniform vec2 fade_area_bottomright;
+
+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;
+
+    /*
+     * We cannot just return here due to a bug in llvmpipe see:
+     * https://bugzilla.freedesktop.org/show_bug.cgi?id=62357
+     */
+    if (x > fade_area_topleft[0] && x < fade_area_bottomright[0] &&
+        y > fade_area_topleft[1] && y < fade_area_bottomright[1]) {
+        float ratio = 1.0;
+        float fade_bottom_start = fade_area_bottomright[1] - vfade_offset;
+        float fade_right_start = fade_area_bottomright[0] - hfade_offset;
+        bool fade_top = y < vfade_offset && fade_edges_top;
+        bool fade_bottom = y > fade_bottom_start && fade_edges_bottom;
+        bool fade_left = x < hfade_offset && fade_edges_left;
+        bool fade_right = x > fade_right_start && fade_edges_right;
+
+        float vfade_scale = height / vfade_offset;
+        if (fade_top) {
+            ratio *= y / vfade_offset;
+        }
+
+        if (fade_bottom) {
+            ratio *= (fade_area_bottomright[1] - y) / (fade_area_bottomright[1] - fade_bottom_start);
+        }
+
+        float hfade_scale = width / hfade_offset;
+        if (fade_left) {
+            ratio *= x / hfade_offset;
+        }
+
+        if (fade_right) {
+            ratio *= (fade_area_bottomright[0] - x) / (fade_area_bottomright[0] - fade_right_start);
+        }
+
+        cogl_color_out *= ratio;
+    }
+}