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https://github.com/dolphin-emu/dolphin
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81 lines
2.3 KiB
C++
81 lines
2.3 KiB
C++
// Copyright 2009 Dolphin Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#include "VideoCommon/BPMemory.h"
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#include <bit>
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// BP state
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// STATE_TO_SAVE
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BPMemory bpmem;
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bool BlendMode::UseLogicOp() const
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{
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// Blending overrides the logicop bit.
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if (blendenable || !logicopenable)
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return false;
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// Fast path for Kirby's Return to Dreamland, they use it with dstAlpha.
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if (logicmode == LogicOp::NoOp)
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return false;
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return true;
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}
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bool FogParams::IsNaNCase() const
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{
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// Check for the case where both a and c are infinity or NaN.
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// On hardware, this results in the following colors:
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//
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// -------------------------------------------------------
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// | A | C | Result | A | C | Result |
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// -------------------------------------------------------
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// | inf | inf | Fogged | inf | nan | Fogged |
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// | inf | -inf | Unfogged | inf | -nan | Unfogged |
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// | -inf | inf | Unfogged | -inf | nan | Unfogged |
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// | -inf | -inf | Unfogged | -inf | -nan | Unfogged |
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// -------------------------------------------------------
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// | nan | inf | Fogged | nan | nan | Fogged |
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// | nan | -inf | Unfogged | nan | -nan | Unfogged |
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// | -nan | inf | Unfogged | -nan | nan | Unfogged |
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// | -nan | -inf | Unfogged | -nan | -nan | Unfogged |
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// -------------------------------------------------------
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//
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// We replicate this by returning A=0, and C=inf for the inf/inf case, otherwise -inf.
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// This ensures we do not pass a NaN to the GPU, and -inf/inf clamp to 0/1 respectively.
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return a.exp == 255 && c_proj_fsel.c_exp == 255;
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}
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float FogParam0::FloatValue() const
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{
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// scale mantissa from 11 to 23 bits
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const u32 integral = (sign << 31) | (exp << 23) | (mant << 12);
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return std::bit_cast<float>(integral);
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}
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float FogParam3::FloatValue() const
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{
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// scale mantissa from 11 to 23 bits
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const u32 integral = (c_sign << 31) | (c_exp << 23) | (c_mant << 12);
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return std::bit_cast<float>(integral);
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}
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float FogParams::GetA() const
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{
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if (IsNaNCase())
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return 0.0f;
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return a.FloatValue();
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}
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float FogParams::GetC() const
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{
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if (IsNaNCase())
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{
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constexpr float inf = std::numeric_limits<float>::infinity();
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return !a.sign && !c_proj_fsel.c_sign ? -inf : inf;
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}
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return c_proj_fsel.FloatValue();
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}
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