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rsx: Add floor workaround for GPUs with rounding issues

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- Mainly affects nvidia where x/w * w can sometimes return a value smaller than x.
  In such conditions, floor(x) will return x-1 if x is an integer which is horribly wrong and exaggerates minor precision drift to great proportions.
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kd-11 2021-06-09 01:37:59 +03:00 • committed by kd-11
parent 2d3fe7ce1c
commit 20bd723e7c
4 changed files with 20 additions and 3 deletions
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18
rpcs3/Emu/RSX/Program/FragmentProgramDecompiler.cpp
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@ -828,7 +828,21 @@ std::string FragmentProgramDecompiler::BuildCode()
"#define _builtin_sqrt(x) sqrt(abs(x))\n"
"#define _builtin_rcp(x) (1. / x)\n"
"#define _builtin_rsq(x) (1. / _builtin_sqrt(x))\n"
"#define _builtin_div(x, y) (x / y)\n\n";
"#define _builtin_div(x, y) (x / y)\n";
if (device_props.has_low_precision_rounding)
{
// NVIDIA has terrible rounding errors interpolating constant values across vertices with different w
// PS3 games blindly rely on interpolating a constant to not change the values
// Calling floor/equality will fail randomly causing a moire pattern
OS <<
"#define _builtin_floor(x) floor(x + 0.000001)\n\n";
}
else
{
OS <<
"#define _builtin_floor floor\n\n";
}
if (properties.has_pkg)
{
@ -954,7 +968,7 @@ bool FragmentProgramDecompiler::handle_sct_scb(u32 opcode)
case RSX_FP_OPCODE_DST: SetDst("$Ty(1.0, $0.y * $1.y, $0.z, $1.w)", OPFLAGS::op_extern); return true;
case RSX_FP_OPCODE_REFL: SetDst(getFunction(FUNCTION::FUNCTION_REFL), OPFLAGS::op_extern); return true;
case RSX_FP_OPCODE_EX2: SetDst("exp2($0.xxxx)"); return true;
case RSX_FP_OPCODE_FLR: SetDst("floor($0)"); return true;
case RSX_FP_OPCODE_FLR: SetDst("_builtin_floor($0)"); return true;
case RSX_FP_OPCODE_FRC: SetDst(getFunction(FUNCTION::FUNCTION_FRACT)); return true;
case RSX_FP_OPCODE_LIT:
SetDst("_builtin_lit($0)");