/*
 * 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
 *
 */

// Specular IBL reflection pipeline:
// Stencil -> BlendWeight -> GlobalFullscreen -> RenderOuter -> RenderInner -> Composite
// -------
//
// This shader stencils the pixels covered by inner probe volumes.  This will
// exclude them from blending operations in the later passes since inner volumes
// always blend at 100%.  Note that this shader only considers pixels that were
// stenciled with the UseIBLSpecularPass value when they were rendered in the forward pass.
// It increases the stencil value if they are in an inner volume.

#include <viewsrg.srgi>

ShaderResourceGroup ObjectSrg : SRG_PerObject
{
    row_major float3x4 m_modelToWorld;

    float4x4 GetWorldMatrix()
    {
        float4x4 modelToWorld = float4x4(
            float4(1, 0, 0, 0),
            float4(0, 1, 0, 0),
            float4(0, 0, 1, 0),
            float4(0, 0, 0, 1));

        modelToWorld[0] = ObjectSrg::m_modelToWorld[0];
        modelToWorld[1] = ObjectSrg::m_modelToWorld[1];
        modelToWorld[2] = ObjectSrg::m_modelToWorld[2];
        return modelToWorld;
    }
}

// Vertex Shader
struct VSInput
{
    float3 m_position : POSITION;
};

struct VSOutput
{
    float4 m_position : SV_Position;
};

VSOutput MainVS(VSInput vsInput)
{
    VSOutput OUT;

    float3 worldPosition = mul(ObjectSrg::GetWorldMatrix(), float4(vsInput.m_position, 1.0)).xyz;
    OUT.m_position = mul(ViewSrg::m_viewProjectionMatrix, float4(worldPosition, 1.0));

    return OUT;
}

// No PS since this shader just sets the stencil