#version 400 core
layout(location = 0) in vec3 vertex_position; // position
layout(location = 1) in vec3 vertex_normal; // colour of each vertex point
layout(location = 2) in vec2 vertex_tex;
layout(location = 3) in vec4 vertex_colour;

out vec2 TexCoord;
out vec4 VertexColour;

// TODO: change c code to match with u_<uniformName>
// also types really matter for shaders!!
uniform mat4 matrix;
uniform mat4 view;
uniform mat4 proj;
uniform vec3 u_lightDir;
uniform float u_lightInfluence; // 0.0 indoors, 1.0 outdoors

void main() {
    gl_Position = proj * view * matrix * vec4(vertex_position, 1.0);

    // max 0.3 so the shadowed side isn't pure black (ambient light)
    float diffuse = max(dot(normalize(vertex_normal), normalize(u_lightDir)), 0.3);

    float intensity = mix(1.0, diffuse, u_lightInfluence);

    vec3 lighting = intensity * vertex_colour.rgb;

    VertexColour = vec4(lighting, vertex_colour.a);
    TexCoord = vertex_tex;
}