// Copyright (C) 2009-2021, Panagiotis Christopoulos Charitos and contributors.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#pragma anki library RtShadows
#pragma anki ray_type 0

#pragma anki mutator ALPHA_TEXTURE 0 1

#include <AnKi/Shaders/Common.glsl>
#include <AnKi/Shaders/Include/ModelTypes.h>

#if ALPHA_TEXTURE == 1
layout(shaderRecordEXT, scalar) buffer b_model
{
	ModelGpuDescriptor u_modelDescriptor;
};

layout(set = 0, binding = 5) uniform sampler u_sampler;

ANKI_BINDLESS_SET(1);
#endif

layout(location = 0) rayPayloadInEXT F32 g_payload;

#pragma anki start ahit

hitAttributeEXT vec2 g_attribs;

ANKI_DEFINE_LOAD_STORE(U16Vec3, 2)
ANKI_DEFINE_LOAD_STORE(MainVertex, ANKI_ALIGNOF(MainVertex))

void main()
{
#if ALPHA_TEXTURE == 1
	const ModelGpuDescriptor model = u_modelDescriptor;
	const MeshGpuDescriptor mesh = model.m_mesh;

	const U32 offset = U32(gl_PrimitiveID) * ANKI_SIZEOF(U16Vec3);
	U16Vec3 indices16;
	load(mesh.m_indexBufferPtr + U64(offset), indices16);
	const UVec3 indices = UVec3(indices16);

	const U64 vertBufferPtr = mesh.m_vertexBufferPtrs[VERTEX_ATTRIBUTE_BUFFER_ID_NORMAL_TANGENT_UV0];

	MainVertex vert0, vert1, vert2;
	load(vertBufferPtr + U64(indices[0] * ANKI_SIZEOF(MainVertex)), vert0);
	load(vertBufferPtr + U64(indices[1] * ANKI_SIZEOF(MainVertex)), vert1);
	load(vertBufferPtr + U64(indices[2] * ANKI_SIZEOF(MainVertex)), vert2);

	const Vec3 barycentrics = Vec3(1.0f - g_attribs.x - g_attribs.y, g_attribs.x, g_attribs.y);

	const Vec2 uv = vert0.m_uv0 * barycentrics.x + vert1.m_uv0 * barycentrics.y + vert2.m_uv0 * barycentrics.z;

	const U32 texIdx = U32(model.m_material.m_bindlessTextureIndices[TEXTURE_CHANNEL_ID_DIFFUSE]);
	const F32 alpha = textureLod(u_bindlessTextures2dF32[nonuniformEXT(texIdx)], u_sampler, uv, 3.0).a;

	g_payload += alpha;

	if(g_payload >= 1.0)
	{
		terminateRayEXT;
	}
#else
	terminateRayEXT;
#endif
}
#pragma anki end

#pragma anki start chit
void main()
{
}
#pragma anki end