SDFShape support for ClearMaterial

[seanpringle]

I tried to add a SphereSDF to the materials example, on the far right, using the same ClearMaterial as the regular Sphere next to it, but the result looks metallic.

Curious to know:

• Is transparency expected to work with SDF shapes?
• If so, any pointers on how I can go about fixing this? My first guess is something to do with Hitinfo at https://github.com/fogleman/pt/blob/master/pt/hit.go#L37, but it seems best to ask for ideas before going down the rabbit hole :-)

package main

import . "github.com/fogleman/pt/pt"

func main() {
	scene := Scene{}
	r := 0.4
	var material Material

	material = DiffuseMaterial(HexColor(0x334D5C))
	scene.Add(NewSphere(V(-2, r, 0), r, material))

	material = SpecularMaterial(HexColor(0x334D5C), 2)
	scene.Add(NewSphere(V(-1, r, 0), r, material))

	material = GlossyMaterial(HexColor(0x334D5C), 2, Radians(50))
	scene.Add(NewSphere(V(0, r, 0), r, material))

	material = TransparentMaterial(HexColor(0x334D5C), 2, Radians(20), 1)
	scene.Add(NewSphere(V(1, r, 0), r, material))

	material = ClearMaterial(2, 0)
	scene.Add(NewSphere(V(2, r, 0), r, material))
	// Added SphereSDF
	scene.Add(NewSDFShape(NewTransformSDF(NewSphereSDF(r), Translate(V(3, r, 0))), material))

	material = MetallicMaterial(HexColor(0xFFFFFF), 0, 1)
	scene.Add(NewSphere(V(0, 1.5, -4), 1.5, material))

	scene.Add(NewCube(V(-1000, -1, -1000), V(1000, 0, 1000), GlossyMaterial(HexColor(0xFFFFFF), 1.4, Radians(20))))
	scene.Add(NewSphere(V(0, 5, 0), 1, LightMaterial(White, 25)))
	camera := LookAt(V(0, 3, 7), V(0, 1, 0), V(0, 1, 0), 30)
	sampler := NewSampler(16, 16)
	renderer := NewRenderer(&scene, &camera, sampler, 960, 540)
	renderer.IterativeRender("out%03d.png", 100)
}

[fogleman]

Yeah, try not doing that inside = false for your SDF shape. That looks like a hacky workaround I was doing.