Add ToT WebGL conformance tests : part 9

conformance/ogles/GL/atan/atan_float_frag_xvaryyvary.frag

+
+/*
+** 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
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+precision highp float;
+#else
+precision mediump float;
+#endif
+#endif
+varying vec4 color;
+
+void main (void)
+{
+        const float M_PI = 3.14159265358979323846;
+        float x = 2.0 * (color.g - 0.5);
+        float y = 2.0 * (color.b - 0.5);
+        const float epsilon = 1.0e-4;
+        gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
+        
+        // Avoid evaluating atan(0, x) for x < epsilon because it's implementation-dependent
+        if(x > epsilon || abs(y) > epsilon)
+        {
+                gl_FragColor = vec4(atan(y, x) / (2.0 * M_PI) + 0.5, 0.0, 0.0, 1.0);
+        }
+}