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# Some compilers may try to optimize comparisons based on the expected
# range of the sources. Check that pessimal cases are handled correctly.
#
# See also https://bugs.freedesktop.org/show_bug.cgi?id=111308
[require]
GLSL >= 1.20
[vertex shader passthrough]
[fragment shader]
#version 120
uniform float a;
uniform float b;
uniform float c;
uniform bool expect_non_zero;
const float epsilon = 0.000000000000000000433681;
void main(void)
{
/* The worrysome optimization only occurs if the compiler believes that
* the mathematical result of the multiply is > 0.
*/
float result = (abs(a) + epsilon) *
(abs(b) + epsilon) *
epsilon;
gl_FragColor = expect_non_zero == (0 < result)
? vec4(0.0, 1.0, 0.0, 1.0)
: vec4(1.0, 0.0, 0.0, 1.0);
}
[test]
# 2**(-61) * 2**(61) * 2**(-61) = 2**(-61)
uniform float a 0.000000000000000000433681
uniform float b 2305843009213693952
uniform int expect_non_zero 1
draw rect -1 -1 1 1
# 2**(-61) * 2**(-28) * 2**(-61) = 2**(-150)
uniform float a 0.000000000000000000433681
uniform float b 0.0000000037252902984619140625
uniform int expect_non_zero 0
draw rect 0 -1 1 1
# 2**(-45) * 2**(-44) * 2**(-61) = 2**(-150)
uniform float a 0.000000000000028421709430404007434844970703125
uniform float b 0.00000000000005684341886080801486968994140625
uniform int expect_non_zero 0
draw rect -1 0 1 1
# 2**(-61) * 2**(-61) * 2**(-61) = 2**(-183)
uniform float a 0.000000000000000000433681
uniform float b 0.000000000000000000433681
uniform int expect_non_zero 0
draw rect 0 0 1 1
probe all rgba 0.0 1.0 0.0 1.0
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