void RenderPolygon(Polygon polygon, Vector2 lightPos)
{
var totalVerts = polygon.Points.Length;
for (var i = 0; i < totalVerts; i++)
{
var vertex = polygon.Points[i] + polygon.position;
var nextVertex = polygon.Points[(i + 1) % totalVerts] + polygon.position;
var startToEnd = nextVertex - vertex;
var normal = new Vector2(startToEnd.Y, -startToEnd.X);
normal.Normalize();
var lightToStart = lightPos - vertex;
Vector2.Dot(ref normal, ref lightToStart, out var nDotL);
if (nDotL > 0)
{
var midpoint = (nextVertex + vertex) * 0.5f;
Debug.DrawLine(vertex, nextVertex, Color.Green);
Debug.DrawLine(midpoint, midpoint + normal * 20, Color.Green);
var point1 = vertex + (Vector2.Normalize(vertex - lightPos) * Screen.Width);
var point2 = nextVertex + (Vector2.Normalize(nextVertex - lightPos) * Screen.Width);
var poly = new Vector2[] { nextVertex, point2, point1, vertex };
_primitiveBatch.DrawPolygon(poly, 4, Color.Black);
}
}
}
void RenderVerts(System.Numerics.Vector2 position, System.Numerics.Vector2 lightPos, System.Numerics.Vector2[] verts)
{
// TODO: should we check to see if the light is inside the verts and early out?
for (var i = 0; i < verts.Length; i++)
{
var vertex = verts[i] + position;
var nextVertex = verts[(i + 1) % verts.Length] + position;
var startToEnd = nextVertex - vertex;
var lightToStart = lightPos - vertex;
var normal = new System.Numerics.Vector2(startToEnd.Y, -startToEnd.X);
normal.Normalize();
var nDotL = System.Numerics.Vector2.Dot(normal, lightToStart);
if (nDotL > 0)
{
var midpoint = (nextVertex + vertex) * 0.5f;
Debug.DrawLine(vertex, nextVertex, Color.Green);
Debug.DrawLine(midpoint, midpoint + normal * 20, Color.Green);
var point1 = nextVertex + (System.Numerics.Vector2.Normalize(nextVertex - lightPos) * Screen.Width);
var point2 = vertex + (System.Numerics.Vector2.Normalize(vertex - lightPos) * Screen.Width);
var poly = new System.Numerics.Vector2[] { nextVertex, point1, point2, vertex };
_vertBuffer[0] = nextVertex;
_vertBuffer[1] = point1;
_vertBuffer[2] = point2;
_vertBuffer[3] = vertex;
_primitiveBatch.DrawPolygon(poly, 4, Color.Black);
}
}
}
