From 4d38d86b2c5e572b1ea5ff4a5a84acb7ab5b87fc Mon Sep 17 00:00:00 2001
From: Zack Rusin <zack@tungstengraphics.com>
Date: Mon, 16 Jun 2008 13:19:41 -0400
Subject: add edge detection to that example

---
 progs/glsl/convolutions.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/progs/glsl/convolutions.c b/progs/glsl/convolutions.c
index be887714c4f..9b9ee532453 100644
--- a/progs/glsl/convolutions.c
+++ b/progs/glsl/convolutions.c
@@ -12,6 +12,7 @@ enum Filter {
    SHARPEN,
    MEAN_REMOVAL,
    EMBOSS,
+   EDGE_DETECT,
    NO_FILTER,
    LAST
 };
@@ -146,6 +147,17 @@ static void fillConvolution(GLint *k,
       color[2] = 0.5;
       color[3] = 0.5;
       break;
+   case EDGE_DETECT:
+      k[0] =  1; k[1] =  1; k[2] =  1;
+      k[3] =  0; k[4] =  0; k[5] =  0;
+      k[6] = -1; k[7] = -1; k[8] = -1;
+
+      *scale = 1.;
+      color[0] = 0.5;
+      color[1] = 0.5;
+      color[2] = 0.5;
+      color[3] = 0.5;
+      break;
    case NO_FILTER:
       k[0] =  0; k[1] =  0; k[2] =  0;
       k[3] =  0; k[4] =  1; k[5] =  0;
@@ -294,6 +306,7 @@ static void menuInit()
    glutAddMenuEntry("Sharpen", SHARPEN);
    glutAddMenuEntry("Mean removal", MEAN_REMOVAL);
    glutAddMenuEntry("Emboss", EMBOSS);
+   glutAddMenuEntry("Edge detect", EDGE_DETECT);
    glutAddMenuEntry("None", NO_FILTER);
 
    glutAddMenuEntry("Quit", QUIT);
-- 
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