1 files changed, 47 insertions, 0 deletions
diff --git a/src/graphics/shaders/chromakey_erosion.frag b/src/graphics/shaders/chromakey_erosion.frag
new file mode 100644
index 0000000..485d141
--- /dev/null
+++ b/src/graphics/shaders/chromakey_erosion.frag
@@ -0,0 +1,47 @@
+//
+//  libavg - Media Playback Engine. 
+//  Copyright (C) 2003-2011 Ulrich von Zadow
+//
+//  This library is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2 of the License, or (at your option) any later version.
+//
+//  This library is distributed in the hope that 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 library; if not, write to the Free Software
+//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//
+//  Current versions can be found at www.libavg.de
+//
+
+uniform sampler2D u_Texture;
+uniform bool u_bIsLast;
+
+#ifndef FRAGMENT_ONLY
+varying vec2 v_TexCoord;
+varying vec4 v_Color;
+#endif
+      
+void main(void)
+{
+    float minAlpha = 1.0;
+    float dx = dFdx(v_TexCoord.x);
+    float dy = dFdy(v_TexCoord.y);
+    for (float y = -1.0; y <= 1.0; ++y) {
+        for (float x = -1.0; x <= 1.0; ++x) {
+           float a = texture2D(u_Texture, v_TexCoord+vec2(x*dx,y*dy)).a;
+           minAlpha = min(minAlpha, a);
+        }
+    }
+    vec4 tex = texture2D(u_Texture, v_TexCoord);
+    if (u_bIsLast) {
+       gl_FragColor = vec4(tex.rgb*minAlpha, minAlpha);
+    } else {
+       gl_FragColor = vec4(tex.rgb, minAlpha);
+    }
+}