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LibSoftGPU: Use AK::SIMD::exp_approximate instead of ::exp

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The approximate version is properly vectorized and results in fewer
stalls than the `::exp` version.
This commit is contained in:
Jelle Raaijmakers 2023-02-17 17:08:51 +01:00 • committed by Andreas Kling
parent f4342c9118
commit f54d9c0a61
1 changed files with 3 additions and 4 deletions
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7
Userland/Libraries/LibSoftGPU/Device.cpp
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@ -39,7 +39,7 @@ static i64 g_num_quads;
using AK::abs; using AK::abs;
using AK::SIMD::any; using AK::SIMD::any;
using AK::SIMD::exp; using AK::SIMD::exp_approximate;
using AK::SIMD::expand4; using AK::SIMD::expand4;
using AK::SIMD::f32x4; using AK::SIMD::f32x4;
using AK::SIMD::i32x4; using AK::SIMD::i32x4;
@ -1277,7 +1277,6 @@ ALWAYS_INLINE void Device::shade_fragments(PixelQuad& quad)
// Calculate fog // Calculate fog
// Math from here: https://opengl-notes.readthedocs.io/en/latest/topics/texturing/aliasing.html // Math from here: https://opengl-notes.readthedocs.io/en/latest/topics/texturing/aliasing.html
// FIXME: exponential fog is not vectorized, we should add a SIMD exp function that calculates an approximation.
if (m_options.fog_enabled) { if (m_options.fog_enabled) {
f32x4 factor; f32x4 factor;
switch (m_options.fog_mode) { switch (m_options.fog_mode) {
@ -1286,12 +1285,12 @@ ALWAYS_INLINE void Device::shade_fragments(PixelQuad& quad)
break; break;
case GPU::FogMode::Exp: { case GPU::FogMode::Exp: {
auto argument = -m_options.fog_density * quad.fog_depth; auto argument = -m_options.fog_density * quad.fog_depth;
factor = exp(argument); factor = exp_approximate(argument);
} break; } break;
case GPU::FogMode::Exp2: { case GPU::FogMode::Exp2: {
auto argument = m_options.fog_density * quad.fog_depth; auto argument = m_options.fog_density * quad.fog_depth;
argument *= -argument; argument *= -argument;
factor = exp(argument); factor = exp_approximate(argument);
} break; } break;
default: default:
VERIFY_NOT_REACHED(); VERIFY_NOT_REACHED();