Index: conformance/ogles/GL2ExtensionTests/fwidth/fwidth_frag_dx.frag |
=================================================================== |
--- conformance/ogles/GL2ExtensionTests/fwidth/fwidth_frag_dx.frag (revision 0) |
+++ conformance/ogles/GL2ExtensionTests/fwidth/fwidth_frag_dx.frag (working copy) |
@@ -0,0 +1,65 @@ |
+ |
+/* |
+** 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 |
+#extension GL_OES_standard_derivatives : enable |
+precision mediump float; |
+#endif |
+ |
+// setting a boundary for cases where screen sizes may exceed the precision |
+// of the arithmetic used. |
+#define SAFETY_BOUND 500.0 |
+ |
+ |
+// Macro to scale/bias the range of output. If input is [-1.0, 1.0], maps to [0.5, 1.0].. |
+// Accounts for precision errors magnified by derivative operation. |
+#define REDUCE_RANGE(A) ((A) + 3.0) / 4.0 |
+ |
+varying vec2 vertXY; |
+ |
+uniform float viewportwidth; |
+uniform float viewportheight; |
+ |
+void main (void) |
+{ |
+ const float M_PI = 3.14159265358979323846; |
+ float cosine; |
+ float sine; |
+ |
+#ifdef GL_OES_standard_derivatives |
+ // fwidth of horizontal sine wave with a period of 128 pixels, scaled to go from -1 to +1 |
+ sine = sin(fract(gl_FragCoord.x / 128.0) * (2.0 * M_PI)); |
+ cosine = REDUCE_RANGE((128.0 / (2.0 * M_PI)) * fwidth(sine)); |
+#else |
+ cosine = 0.5; |
+#endif |
+ |
+ if( (gl_FragCoord.x < SAFETY_BOUND) && (gl_FragCoord.y < SAFETY_BOUND) ) |
+ { |
+ gl_FragColor = vec4(cosine, cosine, cosine, 1.0); |
+ } |
+ else discard; |
+} |
+ |