// 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 TEXTURE_TYPE 0 1

#pragma anki technique vert pixel

#include <AnKi/Shaders/Common.hlsl>

struct Constants
{
	Vec4 m_transform; // x: x scale, y: y scale, z: x transl, w: y transl
	Vec4 m_colorScale;
	Vec4 m_depth; // Used in 3D textures.
};

ANKI_FAST_CONSTANTS(Constants, g_consts)

struct VertIn
{
	Vec2 m_position : POSITION;
	Vec4 m_color : COLOR;
	Vec2 m_uv : TEXCOORD;
};

struct VertOut
{
	Vec2 m_uv : TEXCOORD;
	Vec4 m_color : COLOR;
	Vec4 m_svPosition : SV_POSITION;
};

#if ANKI_VERTEX_SHADER
VertOut main(VertIn input)
{
	VertOut output;

	output.m_uv = input.m_uv;
	output.m_uv.y = 1.0 - output.m_uv.y;
	output.m_color = input.m_color;

	const Vec2 pos = g_consts.m_transform.xy * input.m_position + g_consts.m_transform.zw;
	output.m_svPosition = Vec4(pos, 0.0, 1.0);

	return output;
}
#endif // ANKI_VERTEX_SHADER

#if ANKI_PIXEL_SHADER
SamplerState g_trilinearRepeatSampler : register(s0);
#	if TEXTURE_TYPE == 0
Texture2D<Vec4> g_tex2d : register(t0);
#	else
Texture3D<Vec4> g_tex3d : register(t0);
#	endif

Vec4 main(VertOut input) : SV_TARGET0
{
#	if TEXTURE_TYPE == 0
	const Vec4 rgba = g_tex2d.Sample(g_trilinearRepeatSampler, input.m_uv);
#	else
	const Vec4 rgba = g_tex3d.Sample(g_trilinearRepeatSampler, Vec3(input.m_uv, g_consts.m_depth.x));
#	endif
	Vec3 outColor = input.m_color.rgb * rgba.rgb * g_consts.m_colorScale.rgb;

	if(g_consts.m_colorScale.a == 1.0)
	{
		// Draw a pattern to visualize alpha
		F32 alphaPattern = ((U32(input.m_svPosition.x) / 16u) & 1u) == 1u ? 1.0 : 0.75;
		alphaPattern *= ((U32(input.m_svPosition.y) / 16u) & 1u) == 1u ? 1.0 : 0.75;

		outColor = lerp(Vec3(alphaPattern, alphaPattern, alphaPattern), outColor, rgba.a);
	}

	return Vec4(outColor, 1.0);
}
#endif // ANKI_PIXEL_SHADER