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o3de/Gems/Camera/Code/Source/CameraSystemComponent.cpp

129 lines
4.6 KiB
C++

/*
* Copyright (c) Contributors to the Open 3D Engine Project. For complete copyright and license terms please see the LICENSE at the root of this distribution.
*
* SPDX-License-Identifier: Apache-2.0 OR MIT
*
*/
#include "CameraSystemComponent.h"
#include <AzCore/Math/MatrixUtils.h>
#include <AzCore/Component/TransformBus.h>
#include <Atom/RPI.Public/View.h>
#include <Atom/RPI.Public/ViewportContextBus.h>
namespace Camera
{
void CameraSystemComponent::Reflect(AZ::ReflectContext* context)
{
if (AZ::SerializeContext* serializeContext = azrtti_cast<AZ::SerializeContext*>(context))
{
serializeContext->Class<CameraSystemComponent, AZ::Component>()
->Version(1)
;
}
}
void CameraSystemComponent::Activate()
{
CameraSystemRequestBus::Handler::BusConnect();
ActiveCameraRequestBus::Handler::BusConnect();
CameraNotificationBus::Handler::BusConnect();
}
void CameraSystemComponent::Deactivate()
{
CameraSystemRequestBus::Handler::BusDisconnect();
ActiveCameraRequestBus::Handler::BusDisconnect();
CameraNotificationBus::Handler::BusDisconnect();
}
AZ::EntityId CameraSystemComponent::GetActiveCamera()
{
return m_activeView;
}
const AZ::Transform& CameraSystemComponent::GetActiveCameraTransform()
{
if (m_activeView.IsValid())
{
AZ::TransformBus::EventResult(m_activeViewProperties.transform, m_activeView, &AZ::TransformBus::Events::GetWorldTM);
}
else
{
// In editor, invalid entity ID for the active view denotes the "default editor camera"
// In game, this is an impossible state and if we reached here, we'll likely fail somehow...
m_activeViewProperties.transform = AZ::Transform::CreateIdentity();
using namespace AZ::RPI;
if (auto viewSystem = ViewportContextRequests::Get())
{
if (auto view = viewSystem->GetCurrentView(viewSystem->GetDefaultViewportContextName()))
{
m_activeViewProperties.transform = view->GetCameraTransform();
}
}
}
return m_activeViewProperties.transform;
}
const Configuration& CameraSystemComponent::GetActiveCameraConfiguration()
{
if (m_activeView.IsValid())
{
CameraRequestBus::EventResult(m_activeViewProperties.configuration, m_activeView, &CameraRequestBus::Events::GetCameraConfiguration);
}
else
{
auto& cfg = m_activeViewProperties.configuration;
cfg = Configuration();
// In editor, invalid entity ID for the active view denotes the "default editor camera"
// In game, this is an impossible state and if we reached here, we'll likely fail somehow...
using namespace AZ::RPI;
if (auto viewSystem = ViewportContextRequests::Get())
{
if (auto view = viewSystem->GetCurrentView(viewSystem->GetDefaultViewportContextName()))
{
const auto& viewToClip = view->GetViewToClipMatrix();
cfg.m_fovRadians = AZ::GetPerspectiveMatrixFOV(viewToClip);
// A = f / (n - f)
// B = n * f / (n - f)
// Then...
// B / A
// = (n * f / (n - f)) / (f / (n - f))
// = (n * f) / (f)
// = n
// and...
// n * f / (n - f) = B
// n * ((n - f) / f)^-1 = B
// n * (n/f - 1)^-1 = B
// (n/f - 1)^-1 = B/n
// n/f - 1 = n/B
// f = n/(n/B + 1)
const float A = viewToClip.GetElement(2, 2);
const float B = viewToClip.GetElement(2, 3);
cfg.m_nearClipDistance = B / A;
cfg.m_farClipDistance = cfg.m_nearClipDistance / (cfg.m_nearClipDistance / B + 1.f);
// NB: assumes reversed depth!
AZStd::swap(cfg.m_farClipDistance, cfg.m_nearClipDistance);
// No idea what to do here. Seems to be unused?
cfg.m_frustumWidth = cfg.m_frustumHeight = 1.0f;
}
}
}
return m_activeViewProperties.configuration;
}
void CameraSystemComponent::OnActiveViewChanged(const AZ::EntityId& activeView)
{
m_activeView = activeView;
}
} // namespace Camera