#version 330

#if defined VERTEX_SHADER

in vec3 in_position;
in vec3 in_normal;
in vec2 in_texcoord_0;

uniform mat4 m_proj;
uniform mat4 m_model;
uniform mat4 m_cam;

out vec3 normal;
out vec2 uv;
out vec3 pos;

void main() {
    mat4 mv = m_cam * m_model; 
    vec4 p = mv * vec4(in_position, 1.0);
	gl_Position = m_proj * p;
    mat3 m_normal = transpose(inverse(mat3(mv)));
    normal = m_normal * in_normal;
    uv = in_texcoord_0;
    pos = p.xyz;
}

#elif defined FRAGMENT_SHADER

out vec4 fragColor;
uniform sampler2D texture0;

in vec3 normal;
in vec3 pos;
in vec2 uv;

void main()
{
    float l = dot(normalize(-pos), normalize(normal));
    vec4 color = texture(texture0, uv);
    fragColor = color * 0.25 + color * 0.75 * abs(l);
}

#endif