o3de/Gems/Atom/Feature/Common/Assets/Materials/Pipelines/LowEndPipeline/LowEndForwardPassVertexAndPixel.azsli

/*
 * 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
 *
 */

#pragma once


#include <Atom/Features/Pipeline/Forward/ForwardPassOutput.azsli>

// --- Vertex Shader ---
VsOutput VertexShader(VsInput IN, uint instanceId : SV_InstanceID)
{
    VsSystemValues SV;
    SV.m_instanceId = instanceId;
    VsOutput OUT = EvaluateVertexGeometry(IN, SV, GetMaterialParameters());
    return OUT;
}

// --- Pixel Shader ---

// TODO(MaterialPipeline): Probably replace this with FORCE_EARLY_DEPTH_STENCIL like how it's done in MultiViewForwardPassVertexAndPixel.azsli
#if !OUTPUT_DEPTH
    [earlydepthstencil]
#endif
ForwardPassOutput PixelShader(VsOutput IN, bool isFrontFace : SV_IsFrontFace)
{
    float3 views[MAX_SHADING_VIEWS];
    views[0] = ViewSrg::m_worldPosition.xyz;    // Assume one view for forward pass for now
    
    // ------- Geometry -> Surface -> Lighting -------

    PixelGeometryData geoData = EvaluatePixelGeometry(IN, isFrontFace, GetMaterialParameters());

    Surface surface = EvaluateSurface(IN, geoData, GetMaterialParameters());

    LightingData lightingData = EvaluateLighting(surface, IN.position, views);

    // ------- Output -------

    ForwardPassOutput OUT;

    OUT.m_color.rgb = lightingData.diffuseLighting.rgb + lightingData.specularLighting[0].rgb + lightingData.emissiveLighting.rgb;
    OUT.m_color.a = 1.0;

#if OUTPUT_DEPTH
    // Can be modified in Parallax calculations in EvaluatePixelGeometry
    OUT.m_depth = IN.position.z;
#endif

    return OUT;
}