private static void RasterizeMesh <V>(Texture2D texture, float3 camera, float3 target, SceneObject <V> sceneObject)
where V : struct, INormalVertex <V>
{
var render = new Raster <V, ProjectedVertex>(texture);
// Scene Setup
var(viewMatrix, projectionMatrix) = CameraTools.GetViewAndProjection(texture, camera, target);
// Define a vertex shader that projects a vertex into the NDC.
render.VertexShader = v =>
{
var hPosition = float4(v.Position, 1);
hPosition = mul(hPosition, viewMatrix);
hPosition = mul(hPosition, projectionMatrix);
return(new ProjectedVertex {
Homogeneous = hPosition
});
};
// Define a pixel shader that colors using a constant value
render.PixelShader = p => float4(p.Homogeneous.x / 512.0f, p.Homogeneous.y / 512.0f, 1, 1);
render.DrawMesh(sceneObject.Mesh.ConvertTo(Topology.Lines));
}
private static void RaycastingMesh(Texture2D texture, float3 cameraPosition, float3 lightPosition, float3 target)
{
// View and projection matrices
var viewMatrix = Transforms.LookAtLH(cameraPosition, target, float3.up);
var projectionMatrix =
Transforms.PerspectiveFovLH(pi_over_4, texture.Height / (float)texture.Width, 0.01f, 20);
var scene = new Scene <PositionNormal>();
CreateMeshScene(scene);
// Raycaster to trace rays and check for shadow rays.
var shadower = new Raytracer <ShadowRayPayload, PositionNormal>();
shadower.OnAnyHit += (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 necessary to continue checking other objects
return(HitResult.Stop);
};
// Raycaster to trace rays and lit closest surfaces
var raycaster = new Raytracer <RayPayload, PositionNormal>();
raycaster.OnClosestHit += (IRaycastContext context, PositionNormal attribute, ref RayPayload payload) =>
{
// Move geometry attribute to world space
attribute = attribute.Transform(context.FromGeometryToWorld);
var V = normalize(cameraPosition - attribute.Position);
var L = normalize(lightPosition - attribute.Position);
var lambertFactor = max(0, dot(attribute.Normal, L));
// Check ray to light...
var 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 += (IRaycastContext context, ref RayPayload payload) =>
{
payload.Color = float3(0, 0, 1); // Blue, as the sky.
};
// Render all points of the screen
for (var px = 0; px < texture.Width; px++)
{
for (var py = 0; py < texture.Height; py++)
{
var progress = px * texture.Height + py;
if (progress % 100 == 0)
{
Console.Write("\r" + progress * 100 / (float)(texture.Width * texture.Height) + "% ");
}
var ray = RayDescription.FromScreen(px + 0.5f, py + 0.5f, texture.Width, texture.Height,
inverse(viewMatrix), inverse(projectionMatrix), 0, 1000);
var coloring = new RayPayload();
raycaster.Trace(scene, ray, ref coloring);
texture.Write(px, py, float4(coloring.Color, 1));
}
}
Console.Write("\r" + 100 + "% ");
}
