// Copyright (C) 2009-present, Panagiotis Christopoulos Charitos and contributors.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#pragma anki mutator METHOD 0 1 2 // 0: solid colod, 1: 2D image, 2: Generated

#pragma anki technique vert pixel

#include <AnKi/Shaders/QuadVert.hlsl>

#if ANKI_PIXEL_SHADER
#	include <AnKi/Shaders/Functions.hlsl>
#	include <AnKi/Shaders/Sky.hlsl>
#	include <AnKi/Shaders/TonemappingFunctions.hlsl>
#	include <AnKi/Shaders/Include/TraditionalDeferredShadingTypes.h>
#	include <AnKi/Shaders/Include/MiscRendererTypes.h>

ANKI_FAST_CONSTANTS(TraditionalDeferredSkyboxConstants, g_consts)

SamplerState g_nearestAnyClampSampler : register(s0);
Texture2D g_depthTex : register(t0);

#	if METHOD == 1
SamplerState g_trilinearAnySampler : register(s1);
Texture2D<Vec4> g_envMapTex : register(t1);
#	elif METHOD == 2
SamplerState g_linearAnyClampSampler : register(s1);
Texture2D<Vec4> g_skyLut : register(t1);
#	endif

ConstantBuffer<GlobalRendererConstants> g_globalRendererConsts : register(b0);

Vec4 main(VertOut input) : SV_TARGET0
{
	const Vec2 uv = input.m_uv;
	const F32 depth = g_depthTex.SampleLevel(g_nearestAnyClampSampler, uv, 0.0).r;
	if(depth != 1.0f)
	{
		discard;
	}

#	if METHOD == 0
	ANKI_MAYBE_UNUSED(uv);
	const Vec3 outColor = g_consts.m_solidColor;
#	elif METHOD == 1
	const F32 depthFar = 1.0;
	const Vec2 ndc = uvToNdc(uv);
	const Vec4 worldPos4 = mul(g_consts.m_invertedViewProjectionMat, Vec4(ndc, depthFar, 1.0));
	const Vec3 worldPos = worldPos4.xyz / worldPos4.w;

	const Vec3 eyeToFrag = normalize(worldPos - g_consts.m_cameraPos);

	const Vec2 uv2 = equirectangularMapping(eyeToFrag);
	const Vec3 outColor = g_envMapTex.Sample(g_trilinearAnySampler, uv2).rgb * g_consts.m_scale + g_consts.m_bias;
#	else
	const Vec2 ndc = uvToNdc(uv);
	const Vec4 worldPos4 = mul(g_consts.m_invertedViewProjectionMat, Vec4(ndc, depth, 1.0));
	const Vec3 worldPos = worldPos4.xyz / worldPos4.w;

	const Vec3 eyeToFrag = normalize(worldPos - g_consts.m_cameraPos);

	const F32 sunPower = computeLuminance(g_globalRendererConsts.m_directionalLight.m_diffuseColor);

	const Vec3 outColor =
		computeSkyColor(g_skyLut, g_linearAnyClampSampler, eyeToFrag, -g_globalRendererConsts.m_directionalLight.m_direction, sunPower, false);
#	endif

	return Vec4(outColor, 0.0);
}

#endif // ANKI_PIXEL_SHADER