public override void render(Graphics graphics, Camera camera)
{
if (power > 0 && isVisibleFromCamera(camera))
{
var size = radius * 2f;
var obstacles = Physics.boxcastBroadphase(new RectangleF(entity.transform.position.X - radius, entity.transform.position.Y - radius, size, size), collidesWithLayers);
// Compute the visibility mesh
var visibility = new VisibilityComputer(entity.transform.position, radius);
foreach (var v in obstacles)
{
visibility.addSquareOccluder(v.bounds);
}
// Generate a triangle list from the encounter points
VertexPositionTexture[] vertices;
short[] indices;
var encounters = visibility.computeVisibilityPolygon();
triangleListFromEncounters(encounters, out vertices, out indices);
Core.graphicsDevice.BlendState = BlendState.Additive;
Core.graphicsDevice.RasterizerState = RasterizerState.CullNone;
// Apply the effect
_lightEffect.Parameters["viewProjectionMatrix"].SetValue(entity.scene.camera.viewProjectionMatrix);
_lightEffect.Parameters["lightSource"].SetValue(entity.transform.position);
_lightEffect.Parameters["lightColor"].SetValue(color.ToVector3() * power);
_lightEffect.Parameters["lightRadius"].SetValue(radius);
_lightEffect.Techniques[0].Passes[0].Apply();
// Draw the light on screen, using the triangle fan from the computed
// visibility mesh so that the light only influences the area that can be
// "seen" from the light's position.
Core.graphicsDevice.DrawUserIndexedPrimitives <VertexPositionTexture>
(
PrimitiveType.TriangleList,
vertices,
0,
vertices.Length,
indices,
0,
indices.Length / 3
);
}
}
public override void onAddedToEntity()
{
_lightEffect = entity.scene.content.loadEffect <Effect>("polygonLight", EffectResource.polygonLightBytes);
_lightEffect.Parameters["lightRadius"].SetValue(radius);
_visibility = new VisibilityComputer();
}