Deleted third_party/gles2_book.

third_party/gles2_book/Chapter_13/ProceduralTextures/checker.fs

Index: third_party/gles2_book/Chapter_13/ProceduralTextures/checker.fs
diff --git a/third_party/gles2_book/Chapter_13/ProceduralTextures/checker.fs b/third_party/gles2_book/Chapter_13/ProceduralTextures/checker.fs
deleted file mode 100644
index 305eb469220879782e296edd8eee33a4455b9749..0000000000000000000000000000000000000000
--- a/third_party/gles2_book/Chapter_13/ProceduralTextures/checker.fs
+++ /dev/null
@@ -1,21 +0,0 @@
-#ifdef GL_ES
-precision highp float;
-#endif
-
-uniform int     frequency;
-uniform vec4    color0;
-uniform vec4    color1;
-
-varying vec2    v_st;
-
-void
-main()
-{
-    float   s, t, delta;
-    
-    s = mod(floor(v_st.x * float(frequency * 2)), 2.0);
-    t = mod(floor(v_st.y * float(frequency * 2)), 2.0);    
-    delta = abs(s - t);
-    
-    gl_FragColor = mix(color1, color0, delta);
-}