# Check if 2 double are equals
# IEEE 754 compliant

[require]
GLSL >= 1.30

[vertex shader]
#version 130

void main()
{
    gl_Position = gl_Vertex;
}

[fragment shader]
#version 130

/* Returns the fraction bits of the double-precision floating-point value `a'.*/
uvec2 extractFloat64Frac( uvec2 a )
{
    return uvec2( a.x & 0x000FFFFFu, a.y );
}

/* Returns the exponent bits of the double-precision floating-point value `a'.*/
uint extractFloat64Exp( uvec2 a )
{
    return (a.x>>20) & 0x7FFu;
}

/* Returns 1 if the double-precision floating-point value `a' is equal to the
 * corresponding value `b', and 0 otherwise.  The comparison is performed
 * according to the IEEE Standard for Floating-Point Arithmetic.
 */
bool eq_fp64( uvec2 a, uvec2 b )
{
    uvec2 aFrac;
    uvec2 bFrac;

    aFrac = extractFloat64Frac( a );
    bFrac = extractFloat64Frac( b );
    if (    (    ( extractFloat64Exp( a ) == 0x7FFu )
              && ( ( aFrac.x | aFrac.y ) != 0u ) )
         || (    ( extractFloat64Exp( b ) == 0x7FFu )
              && ( ( bFrac.x | bFrac.y ) != 0u ) )
       ) {
        return false;
    }
    return ( a.y == b.y )
        && ( ( a.x == a.x )
            || ( ( a.y == 0u )
                && ( ( ( a.x | b.x )<<1) == 0u ) )
        );
}

uniform uvec2 a;
uniform uvec2 b;
uniform bool expected;

void main()
{
    /* Generate green if the expected value is producted, red
     * otherwise.
     */
    gl_FragColor = eq_fp64(a,b) == expected
        ? vec4(0.0, 1.0, 0.0, 1.0)
        : vec4(1.0, 0.0, 0.0, 1.0);
}

[test]
# A bunch of tests to run.  The 'uniform' lines set the uniforms.  The
# 'draw rect' line draws a rectangle that covers the whole window.
# The 'probe all' line verifies that every pixel contains the expected
# color.

# Try +0.0 and +0.0
uniform uvec2 a        0x00000000 0x00000000
uniform uvec2 b        0x00000000 0x00000000
uniform bool expected  true
draw rect -1 -1 2 2
probe all rgba 0.0 1.0 0.0 1.0

# Try -0.0 and +0.0
uniform uvec2 a        0x10000000 0x00000000
uniform uvec2 b        0x00000000 0x00000000
uniform bool expected  true
draw rect -1 -1 2 2
probe all rgba 0.0 1.0 0.0 1.0

# Try 0.1 and 0.0
uniform uvec2 a        0x3FB99999 0x9999999A
uniform uvec2 b        0x00000000 0x00000000
uniform bool expected  false
draw rect -1 -1 2 2
probe all rgba 0.0 1.0 0.0 1.0

# Try 1 bit set and 0.0
uniform uvec2 a        0x00000000 0x00000001
uniform uvec2 b        0x00000000 0x00000000
uniform bool expected  false
draw rect -1 -1 2 2
probe all rgba 0.0 1.0 0.0 1.0