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Diffstat (limited to '')
-rw-r--r-- | dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL/atan/atan_float_frag_xvaryyvary_ref.frag | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL/atan/atan_float_frag_xvaryyvary_ref.frag b/dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL/atan/atan_float_frag_xvaryyvary_ref.frag new file mode 100644 index 0000000000..5c341a2a52 --- /dev/null +++ b/dom/canvas/test/webgl-conf/checkout/conformance/ogles/GL/atan/atan_float_frag_xvaryyvary_ref.frag @@ -0,0 +1,71 @@ + +/* +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 +#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); + float atan_c = 0.0; + float scale = 1.0; + float sign = 1.0; + vec4 result = vec4(0.0, 0.0, 0.0, 1.0); + const float epsilon = 1.0e-4; + + // Avoid evaluating atan(0, x) for x < epsilon because it's implementation-dependent + if(x > epsilon || abs(y) > epsilon) + { + if(x < 0.0 ^^ y < 0.0) + { + sign = -1.0; + } + + if(abs(y) <= abs(x)) + { + float c = abs(y / x); + + // Taylors series expansion for atan + for(int i = 1; i < 12; i += 2) + { + atan_c += scale * pow(c, float(i)) / float(i); + scale *= -1.0; + } + + result = vec4(sign * atan_c / (2.0 * M_PI) + 0.5, 0.0, 0.0, 1.0); + } + else + { + float c = abs(x / y); + + // Taylors series expansion for atan + for(int i = 1; i < 12; i += 2) + { + atan_c += scale * pow(c, float(i)) / float(i); + scale *= -1.0; + } + + result = vec4(sign * (M_PI / 2.0 - atan_c) / (2.0 * M_PI) + 0.5, 0.0, 0.0, 1.0); + } + + if(x < 0.0) + if(y < 0.0) result.r -= 0.5; + else if(y > 0.0) result.r += 0.5; + } + + gl_FragColor = result; +} + |