o3de-atom-sampleviewer/Gem/Code/Lib/MaterialFunctors/StacksShaderInputFunctor.cpp

/*
 * 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 <MaterialFunctors/StacksShaderInputFunctor.h>
#include <Atom/RPI.Public/Material/Material.h>
#include <Atom/RPI.Public/Shader/ShaderResourceGroup.h>
#include <AzCore/Math/Matrix4x4.h>

namespace AtomSampleViewer
{
    void StacksShaderInputFunctor::Reflect(AZ::ReflectContext* context)
    {
        if (auto* serializeContext = azrtti_cast<AZ::SerializeContext*>(context))
        {
            serializeContext->Class<StacksShaderInputFunctor, AZ::RPI::MaterialFunctor>()
                ->Version(1)
                ->Field("m_azimuthDegreesIndex", &StacksShaderInputFunctor::m_azimuthDegreesIndex)
                ->Field("m_elevationDegreesIndex", &StacksShaderInputFunctor::m_elevationDegreesIndex)
                ->Field("m_lightDirectionIndex", &StacksShaderInputFunctor::m_lightDirectionIndex)
                ;
        }
    }

    void StacksShaderInputFunctor::Process(RuntimeContext& context)
    {
        float azimuthDegrees = context.GetMaterialPropertyValue<float>(m_azimuthDegreesIndex);
        float elevationDegrees = context.GetMaterialPropertyValue<float>(m_elevationDegreesIndex);

        AZ::Vector3 lightDir = AZ::Vector3(1,0,0) * AZ::Matrix4x4::CreateRotationZ(AZ::DegToRad(elevationDegrees)) * AZ::Matrix4x4::CreateRotationY(AZ::DegToRad(azimuthDegrees));

        float floats[3];
        lightDir.StoreToFloat3(floats);
        context.GetShaderResourceGroup()->SetConstantRaw(m_lightDirectionIndex, floats, 3 * sizeof(float));
    }

} // namespace AtomSampleViewer