Files
test2/source/blender/gpu/shaders/common/gpu_shader_common_math.glsl
Weizhen Huang 77035192c9 Fix #126799: undefined behavior of shader node Arctan2 at (0, 0)
`atan2(0, 0)` is undefined on many platforms. To ensure consistent
result across platforms, we return `0` in this case.

Note only the behavior of the shader node `Artan2` is changed here.
During shading, we might still produce `atan2(0, 0)` internally and
cause different results across platforms, but that usually happens with
single samples and is not obvious, plus checking this condition all the
time is costly. If later we find out it's indeed necessary to change all
the invocation of `atan2(0, 0)`, we could change the wrapper functions
in `metal/compat.h` and `mtl_shader_defines.msl`.

Pull Request: https://projects.blender.org/blender/blender/pulls/126951
2024-09-03 11:44:59 +02:00

244 lines
4.9 KiB
GLSL

/* SPDX-FileCopyrightText: 2019-2023 Blender Authors
*
* SPDX-License-Identifier: GPL-2.0-or-later */
#pragma BLENDER_REQUIRE(gpu_shader_common_math_utils.glsl)
void math_add(float a, float b, float c, out float result)
{
result = a + b;
}
void math_subtract(float a, float b, float c, out float result)
{
result = a - b;
}
void math_multiply(float a, float b, float c, out float result)
{
result = a * b;
}
void math_divide(float a, float b, float c, out float result)
{
result = safe_divide(a, b);
}
void math_power(float a, float b, float c, out float result)
{
if (a >= 0.0) {
result = compatible_pow(a, b);
}
else {
float fraction = mod(abs(b), 1.0);
if (fraction > 0.999 || fraction < 0.001) {
result = compatible_pow(a, floor(b + 0.5));
}
else {
result = 0.0;
}
}
}
void math_logarithm(float a, float b, float c, out float result)
{
result = (a > 0.0 && b > 0.0) ? log2(a) / log2(b) : 0.0;
}
void math_sqrt(float a, float b, float c, out float result)
{
result = (a > 0.0) ? sqrt(a) : 0.0;
}
void math_inversesqrt(float a, float b, float c, out float result)
{
result = inversesqrt(a);
}
void math_absolute(float a, float b, float c, out float result)
{
result = abs(a);
}
void math_radians(float a, float b, float c, out float result)
{
result = radians(a);
}
void math_degrees(float a, float b, float c, out float result)
{
result = degrees(a);
}
void math_minimum(float a, float b, float c, out float result)
{
result = min(a, b);
}
void math_maximum(float a, float b, float c, out float result)
{
result = max(a, b);
}
void math_less_than(float a, float b, float c, out float result)
{
result = (a < b) ? 1.0 : 0.0;
}
void math_greater_than(float a, float b, float c, out float result)
{
result = (a > b) ? 1.0 : 0.0;
}
void math_round(float a, float b, float c, out float result)
{
result = floor(a + 0.5);
}
void math_floor(float a, float b, float c, out float result)
{
result = floor(a);
}
void math_ceil(float a, float b, float c, out float result)
{
result = ceil(a);
}
void math_fraction(float a, float b, float c, out float result)
{
result = a - floor(a);
}
void math_modulo(float a, float b, float c, out float result)
{
result = compatible_fmod(a, b);
}
void math_floored_modulo(float a, float b, float c, out float result)
{
result = (b != 0.0) ? a - floor(a / b) * b : 0.0;
}
void math_trunc(float a, float b, float c, out float result)
{
result = trunc(a);
}
void math_snap(float a, float b, float c, out float result)
{
result = floor(safe_divide(a, b)) * b;
}
void math_pingpong(float a, float b, float c, out float result)
{
result = (b != 0.0) ? abs(fract((a - b) / (b * 2.0)) * b * 2.0 - b) : 0.0;
}
/* Adapted from GODOT-engine math_funcs.h. */
void math_wrap(float a, float b, float c, out float result)
{
result = wrap(a, b, c);
}
void math_sine(float a, float b, float c, out float result)
{
result = sin(a);
}
void math_cosine(float a, float b, float c, out float result)
{
result = cos(a);
}
void math_tangent(float a, float b, float c, out float result)
{
result = tan(a);
}
void math_sinh(float a, float b, float c, out float result)
{
result = sinh(a);
}
void math_cosh(float a, float b, float c, out float result)
{
result = cosh(a);
}
void math_tanh(float a, float b, float c, out float result)
{
result = tanh(a);
}
void math_arcsine(float a, float b, float c, out float result)
{
result = (a <= 1.0 && a >= -1.0) ? asin(a) : 0.0;
}
void math_arccosine(float a, float b, float c, out float result)
{
result = (a <= 1.0 && a >= -1.0) ? acos(a) : 0.0;
}
void math_arctangent(float a, float b, float c, out float result)
{
result = atan(a);
}
/* The behavior of `atan2(0, 0)` is undefined on many platforms, to ensure consistent behavior, we
* return 0 in this case. See !126951. */
void math_arctan2(float a, float b, float c, out float result)
{
result = ((a == 0.0 && b == 0.0) ? 0.0 : atan(a, b));
}
void math_sign(float a, float b, float c, out float result)
{
result = sign(a);
}
void math_exponent(float a, float b, float c, out float result)
{
result = exp(a);
}
void math_compare(float a, float b, float c, out float result)
{
result = (abs(a - b) <= max(c, 1e-5)) ? 1.0 : 0.0;
}
void math_multiply_add(float a, float b, float c, out float result)
{
result = a * b + c;
}
/* See: https://www.iquilezles.org/www/articles/smin/smin.htm. */
void math_smoothmin(float a, float b, float c, out float result)
{
if (c != 0.0) {
float h = max(c - abs(a - b), 0.0) / c;
result = min(a, b) - h * h * h * c * (1.0 / 6.0);
}
else {
result = min(a, b);
}
}
void math_smoothmax(float a, float b, float c, out float result)
{
math_smoothmin(-a, -b, c, result);
result = -result;
}
/* TODO(fclem): Fix dependency hell one EEVEE legacy is removed. */
float math_reduce_max(vec3 a)
{
return max(a.x, max(a.y, a.z));
}
float math_average(vec3 a)
{
return (a.x + a.y + a.z) * (1.0 / 3.0);
}