Selective merge of seminar contribution of Eckholz via pr #31

Co-authored-by: Eric <Windholz.Eric@yahoo.de>

src/artic/CMakeLists.txt

@@ -80,6 +80,7 @@ set(ARTIC_EXTRA_SRC
     ${CMAKE_CURRENT_SOURCE_DIR}/impl/technique/debugtracer.art
     ${CMAKE_CURRENT_SOURCE_DIR}/impl/technique/infobuffer.art
     ${CMAKE_CURRENT_SOURCE_DIR}/impl/technique/pathtracer.art
+    ${CMAKE_CURRENT_SOURCE_DIR}/impl/technique/restir.art
     ${CMAKE_CURRENT_SOURCE_DIR}/impl/technique/photonmapper.art
     ${CMAKE_CURRENT_SOURCE_DIR}/impl/technique/volpathtracer.art
     ${CMAKE_CURRENT_SOURCE_DIR}/impl/technique/wireframe.art

src/artic/impl/camera/common.art

@@ -1,5 +1,8 @@
 // Special camera to satisfy issues when using tracing mode
 fn @make_null_camera() = Camera {
+    near = 0,
+    far  = 0,
+    fov  = 0,
     generate_ray = @ |_, _, _| make_zero_ray(),
     differential = @ |_| ( make_vec3(0,0,0), make_vec3(0,0,0) )
 };

src/artic/impl/camera/fishlens.art

@@ -48,6 +48,9 @@ fn @make_fishlens_camera(eye: Vec3, dir: Vec3, up: Vec3, w: f32, h: f32, mode: F
     }
 
     Camera {
+        near = tmin,
+        far  = tmax,
+        fov  = 0,
         generate_ray = @ |_, x, y| {
             make_ray(eye, compute_d(x,y), tmin, tmax, ray_flag_camera)
         },

src/artic/impl/camera/orthogonal.art

@@ -2,6 +2,9 @@
 fn @make_orthogonal_camera(eye: Vec3, dir: Vec3, up: Vec3, scale: Vec2, tmin: f32, tmax: f32) -> Camera {
     let right = vec3_normalize(vec3_cross(dir, up));
     Camera {
+        near = tmin,
+        far  = tmax,
+        fov  = 0,
         generate_ray = @ |_, x, y| {
             let pos = vec3_add(vec3_add(vec3_mulf(right, scale.x * x), vec3_mulf(up, scale.y * y)), eye);
             make_ray(pos, dir, tmin, tmax, ray_flag_camera)

src/artic/impl/camera/perspective.art

@@ -13,11 +13,14 @@ fn @compute_scale_from_vfov(fov: f32, aspect: f32) -> Vec2 {
 }
 
 // Creates a perspective camera
-fn @make_perspective_camera(eye: Vec3, dir: Vec3, up: Vec3, scale: Vec2, tmin: f32, tmax: f32) -> Camera {
+fn @make_perspective_camera(eye: Vec3, dir: Vec3, up: Vec3, scale: Vec2, tmin: f32, angle: f32, tmax: f32) -> Camera {
     let right = vec3_normalize(vec3_cross(dir, up));
     let view  = make_mat3x3(right, up, dir);
 
     Camera {
+        near = tmin,
+        far  = tmax,
+        fov  = angle,
         generate_ray = @ |_, x, y| {
             let d = vec3_normalize(mat3x3_mul(view, make_vec3(scale.x * x, scale.y * y, 1)));
             make_ray(eye, d, tmin, tmax, ray_flag_camera)
@@ -37,6 +40,9 @@ fn @make_perspective_dof_camera(eye: Vec3, dir: Vec3, up: Vec3, scale: Vec2, ape
     let view  = make_mat3x3(right, up, dir);
 
     Camera {
+        near = tmin,
+        far  = tmax,
+        fov  = 0,
         generate_ray = @ |rnd, x, y| {
             let global_dir = vec3_normalize(mat3x3_mul(view, make_vec3(scale.x * x, scale.y * y, 1)));
             let focus_pos  = vec3_mulf(global_dir, focal_length);

src/artic/impl/emitter.art

@@ -1,13 +1,14 @@
 
 type RayStateInitializer = fn () -> RayPayload;
 
-fn @make_camera_emitter(camera: Camera, iter: i32, spi: i32, sampler: PixelSampler, initState: RayStateInitializer) -> RayEmitter {
+fn @make_camera_emitter(camera: Camera, iter: i32, spi: i32, frame: i32, sampler: PixelSampler, initState: RayStateInitializer) -> RayEmitter {
     @ |sample, x, y, width, height| {
         let mut hash = fnv_init();
         hash = fnv_hash(hash, sample as u32);
         hash = fnv_hash(hash, iter as u32);
         hash = fnv_hash(hash, x as u32);
         hash = fnv_hash(hash, y as u32);
+        hash = fnv_hash(hash, frame as u32);
         let mut rnd = hash /*as RndState*/;
         let (rx, ry) = sampler(&mut rnd, iter * spi + sample, x, y);
         let kx = 2 * (x as f32 + rx) / (width as f32) - 1;

src/artic/impl/pixel_sampler.art

@@ -9,6 +9,12 @@ fn @make_uniform_pixel_sampler() -> PixelSampler {
     }
 }
 
+fn @make_in_the_middle_sampler() -> PixelSampler {
+	@| _, _, _, _| {
+        (0.5, 0.5)
+    }
+}
+
 // --------------------------
 fn @make_mjitt_pixel_sampler(bin_x: u32, bin_y: u32) -> PixelSampler {
 	let F1 = 0xa511e9b3 : u32;

src/artic/impl/sampling.art

@@ -47,6 +47,8 @@ fn @sample_triangle(mut u: f32, mut v: f32) -> (f32, f32) {
 // Probability density function for uniform sphere sampling
 fn @uniform_sphere_pdf() = 1 / (4 * flt_pi);
 
+fn @uniform_hemisphere_pdf() = 1 / (2 * flt_pi);
+
 // Samples a direction uniformly on a sphere
 fn @sample_uniform_sphere(u: f32, v: f32) -> DirSample {
     let c = 2 * v - 1;
@@ -55,6 +57,21 @@ fn @sample_uniform_sphere(u: f32, v: f32) -> DirSample {
     make_dir_sample(c, s, phi, uniform_sphere_pdf())
 }
 
+fn @sample_uniform_hemisphere(u: f32, v: f32) -> DirSample {
+
+    let phi = 2.0 * flt_pi * v;
+
+	let sinTheta = safe_sqrt(1.0 - u * u);
+
+	DirSample
+    {
+        dir = make_vec3(sinTheta * math_builtins::cos(phi),
+        sinTheta * math_builtins::sin(phi),
+        u),
+        pdf = uniform_hemisphere_pdf()
+    }
+}
+
 // Probability density function for equal area sphere sampling
 // Note: Keep in mind this is essentially the same as uniform_sphere, but a bit faster
 fn @equal_area_sphere_pdf() = uniform_sphere_pdf();