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tweak(drawable): Interpolate physics transforms #2055

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tweak(drawable): Interpolate physics transforms #2055

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966f916
tweak(drawable): Interpolate physics transforms
bobtista Sep 15, 2026
32ad9ac
tweak(drawable): Replicate physics interpolation to Generals
bobtista Sep 15, 2026
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8 changes: 7 additions & 1 deletion Generals/Code/GameEngine/Include/GameClient/Drawable.h
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Original file line number Diff line number Diff line change
Expand Up @@ -622,7 +622,13 @@ class Drawable : public Thing,
Real m_totalYaw; ///< Current total yaw for this frame
Real m_totalZ;

PhysicsXformInfo() : m_totalPitch(0), m_totalRoll(0), m_totalYaw(0), m_totalZ(0) { }
Real m_prevTotalPitch;
Real m_prevTotalRoll;
Real m_prevTotalYaw;
Real m_prevTotalZ;

PhysicsXformInfo() : m_totalPitch(0), m_totalRoll(0), m_totalYaw(0), m_totalZ(0),
m_prevTotalPitch(0), m_prevTotalRoll(0), m_prevTotalYaw(0), m_prevTotalZ(0) { }
};

Bool calcPhysicsXform(PhysicsXformInfo& info);
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27 changes: 21 additions & 6 deletions Generals/Code/GameEngine/Source/GameClient/Drawable.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1349,17 +1349,32 @@ void Drawable::applyPhysicsXform(Matrix3D* mtx)
{
if (m_physicsXform != nullptr)
{
// TheSuperHackers @tweak Update the physics transform on every WW Sync only.
// All calculations are originally catered to a 30 fps logic step.
// TheSuperHackers @tweak bobtista 16/09/2026 Advance physics only on WW Sync frames using the 30 fps constants.
if (WW3D::Get_Sync_Frame_Time() != 0)
{
m_physicsXform->m_prevTotalPitch = m_physicsXform->m_totalPitch;
m_physicsXform->m_prevTotalRoll = m_physicsXform->m_totalRoll;
m_physicsXform->m_prevTotalYaw = m_physicsXform->m_totalYaw;
m_physicsXform->m_prevTotalZ = m_physicsXform->m_totalZ;

calcPhysicsXform(*m_physicsXform);
}

mtx->Translate(0.0f, 0.0f, m_physicsXform->m_totalZ);
mtx->Rotate_Y( m_physicsXform->m_totalPitch );
mtx->Rotate_X( -m_physicsXform->m_totalRoll );
mtx->Rotate_Z( m_physicsXform->m_totalYaw );
// TheSuperHackers @tweak bobtista 14/09/2026 Interpolate the rendered transform between
// logic frames, so the motion stays smooth when the render rate is above the logic rate.
// The fractional sync time accumulates in logic time, so a full logic step is always MSEC_PER_LOGICFRAME_REAL.
const Real fractionalMs = (Real)WW3D::Get_Fractional_Sync_Milliseconds();
const Real t = clamp(0.0f, fractionalMs / MSEC_PER_LOGICFRAME_REAL, 1.0f);

const Real interpPitch = m_physicsXform->m_prevTotalPitch + t * (m_physicsXform->m_totalPitch - m_physicsXform->m_prevTotalPitch);
const Real interpRoll = m_physicsXform->m_prevTotalRoll + t * (m_physicsXform->m_totalRoll - m_physicsXform->m_prevTotalRoll);
const Real interpYaw = m_physicsXform->m_prevTotalYaw + t * (m_physicsXform->m_totalYaw - m_physicsXform->m_prevTotalYaw);
const Real interpZ = m_physicsXform->m_prevTotalZ + t * (m_physicsXform->m_totalZ - m_physicsXform->m_prevTotalZ);

mtx->Translate(0.0f, 0.0f, interpZ);
mtx->Rotate_Y( interpPitch );
mtx->Rotate_X( -interpRoll );
mtx->Rotate_Z( interpYaw );
}
}

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8 changes: 7 additions & 1 deletion GeneralsMD/Code/GameEngine/Include/GameClient/Drawable.h
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Original file line number Diff line number Diff line change
Expand Up @@ -622,7 +622,13 @@ class Drawable : public Thing,
Real m_totalYaw; ///< Current total yaw for this frame
Real m_totalZ;

PhysicsXformInfo() : m_totalPitch(0), m_totalRoll(0), m_totalYaw(0), m_totalZ(0) { }
Real m_prevTotalPitch;
Real m_prevTotalRoll;
Real m_prevTotalYaw;
Real m_prevTotalZ;

PhysicsXformInfo() : m_totalPitch(0), m_totalRoll(0), m_totalYaw(0), m_totalZ(0),
m_prevTotalPitch(0), m_prevTotalRoll(0), m_prevTotalYaw(0), m_prevTotalZ(0) { }
};

Bool calcPhysicsXform(PhysicsXformInfo& info);
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27 changes: 21 additions & 6 deletions GeneralsMD/Code/GameEngine/Source/GameClient/Drawable.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1351,17 +1351,32 @@ void Drawable::applyPhysicsXform(Matrix3D* mtx)
{
if (m_physicsXform != nullptr)
{
// TheSuperHackers @tweak Update the physics transform on every WW Sync only.
// All calculations are originally catered to a 30 fps logic step.
// TheSuperHackers @tweak bobtista 16/09/2026 Advance physics only on WW Sync frames using the 30 fps constants.
if (WW3D::Get_Sync_Frame_Time() != 0)
{
m_physicsXform->m_prevTotalPitch = m_physicsXform->m_totalPitch;
m_physicsXform->m_prevTotalRoll = m_physicsXform->m_totalRoll;
m_physicsXform->m_prevTotalYaw = m_physicsXform->m_totalYaw;
m_physicsXform->m_prevTotalZ = m_physicsXform->m_totalZ;

calcPhysicsXform(*m_physicsXform);
}

mtx->Translate(0.0f, 0.0f, m_physicsXform->m_totalZ);
mtx->Rotate_Y( m_physicsXform->m_totalPitch );
mtx->Rotate_X( -m_physicsXform->m_totalRoll );
mtx->Rotate_Z( m_physicsXform->m_totalYaw );
// TheSuperHackers @tweak bobtista 14/09/2026 Interpolate the rendered transform between
// logic frames, so the motion stays smooth when the render rate is above the logic rate.
// The fractional sync time accumulates in logic time, so a full logic step is always MSEC_PER_LOGICFRAME_REAL.
const Real fractionalMs = (Real)WW3D::Get_Fractional_Sync_Milliseconds();
const Real t = clamp(0.0f, fractionalMs / MSEC_PER_LOGICFRAME_REAL, 1.0f);

const Real interpPitch = m_physicsXform->m_prevTotalPitch + t * (m_physicsXform->m_totalPitch - m_physicsXform->m_prevTotalPitch);
const Real interpRoll = m_physicsXform->m_prevTotalRoll + t * (m_physicsXform->m_totalRoll - m_physicsXform->m_prevTotalRoll);
const Real interpYaw = m_physicsXform->m_prevTotalYaw + t * (m_physicsXform->m_totalYaw - m_physicsXform->m_prevTotalYaw);
const Real interpZ = m_physicsXform->m_prevTotalZ + t * (m_physicsXform->m_totalZ - m_physicsXform->m_prevTotalZ);

mtx->Translate(0.0f, 0.0f, interpZ);
mtx->Rotate_Y( interpPitch );
mtx->Rotate_X( -interpRoll );
mtx->Rotate_Z( interpYaw );
}
}

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