Geometry shader

#version 330

layout(points) in;
layout(triangle_strip,max_vertices=36) out;

in vec4 pass_Color[];
in vec2 pass_TextureCoord[];

out vec4 geom_Color;

void main() {
    for (int i = 0; i < gl_in.length(); i++) {
        vec4 inPos = gl_in[i].gl_Position;
        geom_Color = pass_Color[i];

        //front
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, 0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, 0.5, 0.0)); //tl
        EmitVertex();
        EndPrimitive();

        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, 0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, 0.5, 0.0)); //br
        EmitVertex();
        EndPrimitive();

        //back
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, -0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, -0.5, 0.0)); //br
        EmitVertex();
        EndPrimitive();

        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, -0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, -0.5, 0.0)); //tl
        EmitVertex();
        EndPrimitive();

        //right
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, 0.5, 0.0)); //br
        EmitVertex();
        EndPrimitive();

        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, -0.5, 0.0)); //tl
        EmitVertex();
        EndPrimitive();

        //left
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, 0.5, 0.0)); //br
        EmitVertex();
        EndPrimitive();

        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, -0.5, 0.0)); //tl
        EmitVertex();
        EndPrimitive();

        //top
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, 0.5, 0.0)); //br
        EmitVertex();
        EndPrimitive();

        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, 0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, 0.5, -0.5, 0.0)); //tl
        EmitVertex();
        EndPrimitive();

        //bottom
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, 0.5, 0.0)); //br
        EmitVertex();
        EndPrimitive();

        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(-0.5, -0.5, -0.5, 0.0)); //bl
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, 0.5, 0.0)); //tr
        EmitVertex();
        gl_Position = gl_ModelViewProjectionMatrix * (inPos + vec4(0.5, -0.5, -0.5, 0.0)); //tl
        EmitVertex();
        EndPrimitive();
    }
}