#version 450
/* Copyright (c) 2024-2025, Sascha Willems
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 the "License";
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

layout (location = 0) in vec3 inNormal;
layout (location = 1) in vec4 inColor;
layout (location = 2) in vec3 inWorldPos;

layout (location = 0) out vec4 outColor;
layout (location = 1) out vec4 outPositionDepth;
layout (location = 2) out vec4 outNormal;
layout (location = 3) out vec4 outAlbedo;

layout (constant_id = 0) const float NEAR_PLANE = 0.1f;
layout (constant_id = 1) const float FAR_PLANE = 256.0f;

float linearDepth(float depth)
{
	float z = depth * 2.0f - 1.0f; 
	return (2.0f * NEAR_PLANE * FAR_PLANE) / (FAR_PLANE + NEAR_PLANE - z * (FAR_PLANE - NEAR_PLANE));	
}

void main() 
{
	outPositionDepth = vec4(inWorldPos, 1.0);

	vec3 N = normalize(inNormal);
	N.y = -N.y;
	outNormal = vec4(N, 1.0);

	outAlbedo = inColor;

	// Store linearized depth in alpha component
	outPositionDepth.a = linearDepth(gl_FragCoord.z);

	// Write color attachments to avoid undefined behaviour (validation error)
	outColor = vec4(0.0);
}