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Diffstat (limited to '')
| -rw-r--r-- | dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL2ExtensionTests/fwidth/fwidth_frag_dy.frag | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL2ExtensionTests/fwidth/fwidth_frag_dy.frag b/dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL2ExtensionTests/fwidth/fwidth_frag_dy.frag new file mode 100644 index 0000000000..cd555f623e --- /dev/null +++ b/dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL2ExtensionTests/fwidth/fwidth_frag_dy.frag @@ -0,0 +1,48 @@ + +/* +Copyright (c) 2019 The Khronos Group Inc. +Use of this source code is governed by an MIT-style license that can be +found in the LICENSE.txt file. +*/ + + +#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 vertical sine wave with a period of 128 pixels, scaled to go from -1 to +1 + sine = sin(fract(gl_FragCoord.y / 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; +} + |