-- Vertex
#version 400 core

layout(location = 0) in vec4 in_Position;
layout(location = 1) in vec2 in_TexCoord;

out vec2 v_TexCoord;

void main()
{
	gl_Position = in_Position;
	v_TexCoord = in_TexCoord;
}

-- Fragment
#version 400 core

in vec3 gs_Normal[1];
in vec2 gs_TexCoord[1];
out vec4 out_Color;
uniform sampler2D terrain;

void main()
{
	out_Color = texture(terrain, gs_TexCoord[0]);
}

-- Geometry
#version 400 core

uniform transform {
	mat4 MVP;
	mat3 Normal;
} Transform;


in vec2 v_TexCoord[1];
out vec3 gs_Normal[1];
out vec2 gs_TexCoord[1];

layout(points) in;
layout(triangle_strip, max_vertices=24) out;

void main()
{
	vec4 point = gl_in[0].gl_Position;
	vec4 points[8];
	vec3 normals[3];
	vec2 texcoords[4];

	points[0] = point - vec4(1, 1, 1, 0);
	points[1] = point - vec4(0, 1, 1, 0);
	points[2] = point - vec4(1, 0, 1, 0);
	points[3] = point - vec4(0, 0, 1, 0);
	points[4] = point - vec4(1, 1, 0, 0);
	points[5] = point - vec4(0, 1, 0, 0);
	points[6] = point - vec4(1, 0, 0, 0);
	points[7] = point - vec4(0, 0, 0, 0);

	normals[0] = vec3(0,0,1);
	normals[1] = vec3(0,1,0);
	normals[2] = vec3(1,0,0);

	texcoords[0] = vec2(v_TexCoord[0].s + 0.0625,	v_TexCoord[0].t + 0.0625);
	texcoords[1] = vec2(v_TexCoord[0].s,			v_TexCoord[0].t + 0.0625);
	texcoords[2] = vec2(v_TexCoord[0].s + 0.0625,	v_TexCoord[0].t);
	texcoords[3] = vec2(v_TexCoord[0].s,			v_TexCoord[0].t);

	//Front Face

	gl_Position = Transform.MVP * points[0]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[0]; EmitVertex();
	gl_Position = Transform.MVP * points[1]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[1]; EmitVertex();
	gl_Position = Transform.MVP * points[2]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[2]; EmitVertex();
	gl_Position = Transform.MVP * points[3]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[3]; EmitVertex();
	EndPrimitive();

	//Back Face
	gl_Position = Transform.MVP * points[4]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[0]; EmitVertex();
	gl_Position = Transform.MVP * points[5]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[1]; EmitVertex();
	gl_Position = Transform.MVP * points[6]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[2]; EmitVertex();
	gl_Position = Transform.MVP * points[7]; gs_Normal[0] = Transform.Normal * normals[0]; gs_TexCoord[0] = texcoords[3]; EmitVertex();
	EndPrimitive();

	//Bottom Face
	gl_Position = Transform.MVP * points[0]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[0]; EmitVertex();
	gl_Position = Transform.MVP * points[1]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[1]; EmitVertex();
	gl_Position = Transform.MVP * points[4]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[2]; EmitVertex();
	gl_Position = Transform.MVP * points[5]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[3]; EmitVertex();
	EndPrimitive();

	//Top Face
	gl_Position = Transform.MVP * points[2]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[0]; EmitVertex();
	gl_Position = Transform.MVP * points[3]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[1]; EmitVertex();
	gl_Position = Transform.MVP * points[6]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[2]; EmitVertex();
	gl_Position = Transform.MVP * points[7]; gs_Normal[0] = Transform.Normal * normals[1]; gs_TexCoord[0] = texcoords[3]; EmitVertex();
	EndPrimitive();

	//Left Face
	gl_Position = Transform.MVP * points[1]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[0]; EmitVertex();
	gl_Position = Transform.MVP * points[3]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[1]; EmitVertex();
	gl_Position = Transform.MVP * points[5]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[2]; EmitVertex();
	gl_Position = Transform.MVP * points[7]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[3]; EmitVertex();
	EndPrimitive();

	//Right Face
	gl_Position = Transform.MVP * points[0]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[0]; EmitVertex();
	gl_Position = Transform.MVP * points[2]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[1]; EmitVertex();
	gl_Position = Transform.MVP * points[4]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[2]; EmitVertex();
	gl_Position = Transform.MVP * points[6]; gs_Normal[0] = Transform.Normal * normals[2]; gs_TexCoord[0] = texcoords[3]; EmitVertex();
	EndPrimitive();

}