static void SimpleRaycast(Texture2D texture)
{
Raytracer <RayPayload, float3> raycaster = new Raytracer <RayPayload, float3>();
// View and projection matrices
float4x4 viewMatrix = Transforms.LookAtLH(float3(2, 1f, 4), float3(0, 0, 0), float3(0, 1, 0));
float4x4 projectionMatrix =
Transforms.PerspectiveFovLH(pi_over_4, texture.Height / (float)texture.Width, 0.01f, 20);
Scene <float3> scene = new Scene <float3>();
CreateScene(scene);
raycaster.OnClosestHit += delegate(IRaycastContext context, float3 attribute, ref RayPayload payload)
{
payload.Color = attribute;
};
for (float px = 0.5f; px < texture.Width; px++)
{
for (float py = 0.5f; py < texture.Height; py++)
{
RayDescription ray = RayDescription.FromScreen(px, py, texture.Width, texture.Height,
inverse(viewMatrix), inverse(projectionMatrix), 0, 1000);
RayPayload coloring = new RayPayload();
raycaster.Trace(scene, ray, ref coloring);
texture.Write((int)px, (int)py, float4(coloring.Color, 1));
}
}
}
static void LitRaycast(Texture2D texture)
{
// Scene Setup
float3 CameraPosition = float3(3, 2f, 4);
float3 LightPosition = float3(3, 5, -2);
// View and projection matrices
float4x4 viewMatrix = Transforms.LookAtLH(CameraPosition, float3(0, 1, 0), float3(0, 1, 0));
float4x4 projectionMatrix =
Transforms.PerspectiveFovLH(pi_over_4, texture.Height / (float)texture.Width, 0.01f, 20);
Scene <PositionNormal> scene = new Scene <PositionNormal>();
CreateScene(scene);
// Raycaster to trace rays and check for shadow rays.
Raytracer <ShadowRayPayload, PositionNormal> shadower = new Raytracer <ShadowRayPayload, PositionNormal>();
shadower.OnAnyHit += delegate(IRaycastContext context, PositionNormal attribute,
ref ShadowRayPayload payload)
{
// If any object is found in ray-path to the light, the ray is shadowed.
payload.Shadowed = true;
// No neccessary to continue checking other objects
return(HitResult.Stop);
};
// Raycaster to trace rays and lit closest surfaces
Raytracer <RayPayload, PositionNormal> raycaster = new Raytracer <RayPayload, PositionNormal>();
raycaster.OnClosestHit +=
delegate(IRaycastContext context, PositionNormal attribute, ref RayPayload payload)
{
// Move geometry attribute to world space
attribute = attribute.Transform(context.FromGeometryToWorld);
float3 V = normalize(CameraPosition - attribute.Position);
float3 L = normalize(LightPosition - attribute.Position);
float lambertFactor = max(0, dot(attribute.Normal, L));
// Check ray to light...
ShadowRayPayload shadow = new ShadowRayPayload();
shadower.Trace(scene,
RayDescription.FromTo(
attribute.Position +
attribute.Normal * 0.001f, // Move an epsilon away from the surface to avoid self-shadowing
LightPosition), ref shadow);
payload.Color = shadow.Shadowed ? float3(0, 0, 0) : float3(1, 1, 1) * lambertFactor;
};
raycaster.OnMiss += delegate(IRaycastContext context, ref RayPayload payload)
{
payload.Color = float3(0, 0, 1); // Blue, as the sky.
};
// Render all points of the screen
for (int px = 0; px < texture.Width; px++)
{
for (int py = 0; py < texture.Height; py++)
{
RayDescription ray = RayDescription.FromScreen(px + 0.5f, py + 0.5f, texture.Width, texture.Height,
inverse(viewMatrix), inverse(projectionMatrix), 0, 1000);
RayPayload coloring = new RayPayload();
raycaster.Trace(scene, ray, ref coloring);
texture.Write(px, py, float4(coloring.Color, 1));
}
}
}
