RubyGL::Util

# File lib/rubygl/util.rb, line 13
def self.gen_index_arrays(vertex_array, components)
    unique_points, point_indices, index_hash = [], [], {}
    
    curr_index = 0
    vertex_array.each_slice(components) { |point|
        index = index_hash[point]
        
        if index then
            point_indices.push(index)
        else
            unique_points.push(point)
            point_indices.push(curr_index)
            
            index_hash[point] = curr_index
            curr_index += 1
        end
    }
    unique_points.flatten!
    
    [unique_points, point_indices]
end

# File lib/rubygl/util.rb, line 42
def self.gen_vertex_normals(indices, vertices)
    normals = Array.new(vertices.size, Vec3.new)
    
    indices.each_slice(3) { |i1, i2, i3|
        # 3 Components Per Vertex (Index References 3 Components)
        adj_i1, adj_i2, adj_i3 = i1 * 3, i2 * 3, i3 * 3
        
        # Construct Triangle Vertices
        v1 = Vec3.new(vertices[adj_i1..adj_i1 + 2])
        v2 = Vec3.new(vertices[adj_i2..adj_i2 + 2])
        v3 = Vec3.new(vertices[adj_i3..adj_i3 + 2])
        
        d1 = v2 - v1
        d2 = v3 - v2
        
        normal = d1.cross(d2)
        normal.norm!
        
        normals[i1] += normal
        normals[i2] += normal
        normals[i3] += normal
    }
    
    # Normalize All Vectors And Convert From Vec3 To Flat Array
    normals.map! { |normal_vector|
        normal_vector.norm!
        
        normal_vector.to_a
    }
    normals.flatten!
    
    normals
end

# File lib/rubygl/util.rb, line 6
def self.overflow_wrap(array, index)
    array[index % array.size]
end