#version 450

layout(triangles, invocations = 6) in;
layout(triangle_strip, max_vertices = 3) out;


struct PointShadowMapSet
{
    uint entity_id;
    uint shadow_id;
    uint shadow_texture_id;   
    uint frame_buffer_id;
    float near_plane;
    float far_plane;
    uint padding[2];
    mat4 light_space_proj;
    mat4 light_space_view[6];

};


//Push constants updated for each light
layout(binding = 0) uniform shadow_per_frame
{
	vec3 camera_pos;
	uint shadow_idxs;
};

layout (std430, binding = 7) readonly buffer point_shadow_map_sets
{
	PointShadowMapSet point_shadows[];
};

layout (location=0) in VS_OUT
{
	vec2 vsUV;
    flat uint vsMaterialID;
}vs_in[];

layout (location=0) out GEOM_OUT
{
	vec2 vsUV;
    flat uint vsMaterialID; 
    vec4 frag_pos;
    flat uint shad_idx;
    flat vec3 light_pos;
}geom_out;

void main()
{      
	mat4 view = point_shadows[shadow_idxs].light_space_view[gl_InvocationID];
	mat4 proj = point_shadows[shadow_idxs].light_space_proj;
    
    mat3 rot_mat = mat3(view); 
    vec3 d = vec3(view[3]); // Column-major translation column
    vec3 light_pos = -d * rot_mat;

	for (int i = 0; i < 3; ++i)
	{
        geom_out.light_pos = light_pos;
        geom_out.shad_idx = shadow_idxs;
        geom_out.frag_pos = gl_in[i].gl_Position;
		gl_Layer = gl_InvocationID;
        vec4 clip_space_pos = proj * view * gl_in[i].gl_Position;
        
        gl_Position = clip_space_pos;

        geom_out.vsMaterialID = vs_in[gl_InvocationID].vsMaterialID;
        geom_out.vsUV = vs_in[gl_InvocationID].vsUV;

        EmitVertex();
	}
	EndPrimitive();
}