Add ToT WebGL conformance tests : part 9

conformance/ogles/GL/log/log_vec3_frag_xvary01_ref.frag

Index: conformance/ogles/GL/log/log_vec3_frag_xvary01_ref.frag
===================================================================
--- conformance/ogles/GL/log/log_vec3_frag_xvary01_ref.frag	(revision 0)
+++ conformance/ogles/GL/log/log_vec3_frag_xvary01_ref.frag	(working copy)
@@ -0,0 +1,53 @@
+
+/*
+** Copyright (c) 2012 The Khronos Group Inc.
+**
+** Permission is hereby granted, free of charge, to any person obtaining a
+** copy of this software and/or associated documentation files (the
+** "Materials"), to deal in the Materials without restriction, including
+** without limitation the rights to use, copy, modify, merge, publish,
+** distribute, sublicense, and/or sell copies of the Materials, and to
+** permit persons to whom the Materials are furnished to do so, subject to
+** the following conditions:
+**
+** The above copyright notice and this permission notice shall be included
+** in all copies or substantial portions of the Materials.
+**
+** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
+*/
+
+
+#ifdef GL_ES
+precision mediump float;
+#endif
+varying vec4 color;
+
+void main (void)
+{
+	vec3 x = (color.rgb + 0.01) / 1.01;
+	vec3 y = vec3(0.0);
+	vec3 z;   // x-1 / x+1
+	int n = 50;
+
+	// ln(x) = 2[x-1 + 1 (x-1)^3 + 1 (x-1)^5 + ...] for x > 0
+	//          [x+1   3 (x+1)     5 (x+1)        ]
+	// Note: z will always be negative between 0.01 and 1.0 and
+	// so will y since it is raised to an odd power, and the shader spec
+	// does not support pow(-x, y) where y is not a compile time constant
+	z = abs((x - 1.0) / (x + 1.0));
+	vec3 p = z;
+	for(int i = 1; i <= 101; i += 2)
+	{
+		y += p / float(i);
+		p *= z * z;
+	}
+	y *= -2.0;
+
+	gl_FragColor = vec4(y / -4.61, 1.0);
+}