#version 450
#extension GL_GOOGLE_include_directive : enable

#include "lib/common.glsl"
#include "lib/forward_vertex.glsl"

CAMERA(0, camera)
STORAGE_BUFFER(1, Object, objects)

// Attributes
IN(0, vec3, position)
IN(1, vec3, normal)
IN(2, vec2, texcoord)

void main() 
{
	out_object = gl_InstanceIndex;
	mat4 m = objects.item[out_object].model;

	vec3 center = (m * vec4(0, 0, 0, 1.0)).xyz;
	vec3 lookDirection = normalize(center - camera.Eye.xyz);
	vec3 up = vec3(0, 1, 0);

	vec3 right = normalize(cross(up, lookDirection));
	up = normalize(cross(lookDirection, right));

	out_world_position = center + 
		right * in_position.x +
		up * in_position.y;

	// texture coords
	out_color.xy = in_texcoord;

	// gbuffer view position
	out_view_position = (camera.View * vec4(out_world_position.xyz, 1.0)).xyz;

	// world normal is always facing the camera
	out_world_normal = normalize(center - camera.Eye.xyz);

	// vertex clip space position
	gl_Position = camera.Proj * vec4(out_view_position, 1);
}