#version 450
/* Copyright (c) 2019-2024, 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 (binding = 1) uniform sampler2D samplerColor;

layout (location = 0) in vec2 inUV;
layout (location = 1) in float inLodBias;
layout (location = 2) in vec3 inNormal;
layout (location = 3) in vec3 inViewVec;
layout (location = 4) in vec3 inLightVec;

layout (location = 0) out vec4 outFragColor;

void main() 
{
	vec4 color = texture(samplerColor, inUV, inLodBias);

	vec3 N = normalize(inNormal);
	vec3 L = normalize(inLightVec);
	vec3 V = normalize(inViewVec);
	vec3 R = reflect(-L, N);
	vec3 diffuse = max(dot(N, L), 0.0) * vec3(1.0);
	float specular = pow(max(dot(R, V), 0.0), 16.0) * color.a;

	outFragColor = vec4(diffuse * color.rgb + specular, 1.0);	
}