7842 - new directory organization

Baremetal is now the default build target and therefore has its sources
at the top-level. Baremetal programs build using the phase-2 Mu toolchain
that requires a Linux kernel. This phase-2 codebase which used to be at
the top-level is now under the linux/ directory. Finally, the phase-2 toolchain,
while self-hosting, has a way to bootstrap from a C implementation, which
is now stored in linux/bootstrap. The bootstrap C implementation uses some
literate programming tools that are now in linux/bootstrap/tools.

So the whole thing has gotten inverted. Each directory should build one
artifact and include the main sources (along with standard library). Tools
used for building it are relegated to sub-directories, even though those
tools are often useful in their own right, and have had lots of interesting
programs written using them.

A couple of things have gotten dropped in this process:
  - I had old ways to run on just a Linux kernel, or with a Soso kernel.
    No more.
  - I had some old tooling for running a single test at the cursor. I haven't
    used that lately. Maybe I'll bring it back one day.

The reorg isn't done yet. Still to do:
  - redo documentation everywhere. All the README files, all other markdown,
    particularly vocabulary.md.
  - clean up how-to-run comments at the start of programs everywhere
  - rethink what to do with the html/ directory. Do we even want to keep
    supporting it?

In spite of these shortcomings, all the scripts at the top-level, linux/
and linux/bootstrap are working. The names of the scripts also feel reasonable.
This is a good milestone to take stock at.

1 files changed, 0 insertions, 112 deletions

diff --git a/apps/raytracing/main.cc b/apps/raytracing/main.cc
deleted file mode 100644
index 35177279..00000000
--- a/apps/raytracing/main.cc
+++ /dev/null
@@ -1,112 +0,0 @@
-#include <iostream>
-
-// print float in some sort of intuitive hex that also helps visualize the underlying bits
-void p(std::ostream &out, float f) {
-    int bits = *(int*)&f;
-    // sign
-    if (bits & 0x80000000) {
-      out << '-';
-    }
-    // mantissa
-    int mantissa = bits & 0x007fffff;
-    int exponent = (bits & 0x7f800000) >> 23;
-    out << std::hex << mantissa << "P" << std::dec << (exponent-127);
-}
-
-#include "color.h"
-#include "ray.h"
-#include "vec3.h"
-
-color ray_color(const ray& r) {
-//?     std::cerr << "r.dir: " << r.direction() << '\n';
-//?     std::cerr << "r.dir length: ";
-//?       p(std::cerr, r.direction().length());
-//?       std::cerr << '\n';
-    vec3 unit_direction = unit_vector(r.direction());
-//?     std::cerr << "r.dir normalized: " << unit_direction << '\n';
-    float t = 0.5*(unit_direction.y() + 1.0);
-//?     std::cerr << "t: ";
-//?       p(std::cerr, t);
-//?       std::cerr << '\n';
-    vec3 whitening = (1.0-t)*color(1.0, 1.0, 1.0);
-//?     std::cerr << "whitening: ";
-//?       p(std::cerr, whitening.x());
-//?       std::cerr << " ";
-//?       p(std::cerr, whitening.y());
-//?       std::cerr << " ";
-//?       p(std::cerr, whitening.z());
-//?       std::cerr << "\n";
-    vec3 base = t*color(0.5, 0.7, 1.0);
-//?     std::cerr << "base: ";
-//?       p(std::cerr, base.x());
-//?       std::cerr << " ";
-//?       p(std::cerr, base.y());
-//?       std::cerr << " ";
-//?       p(std::cerr, base.z());
-//?       std::cerr << "\n";
-    vec3 result = base + whitening;
-//?     std::cerr << "result: ";
-//?       p(std::cerr, result.x());
-//?       std::cerr << " ";
-//?       p(std::cerr, result.y());
-//?       std::cerr << " ";
-//?       p(std::cerr, result.z());
-//?       std::cerr << "\n";
-    return result;
-}
-
-int main() {
-
-    // Image
-    const float aspect_ratio = 16.0 / 9.0;
-//?     std::cerr << "aspect ratio: " << aspect_ratio << ' ' << std::hex << *(int*)&aspect_ratio << '\n';
-    const int image_width = 400;
-    const int image_height = static_cast<int>(image_width / aspect_ratio);
-
-    // Camera
-
-    float viewport_height = 2.0;
-//?     std::cerr << "viewport height: " << viewport_height << ' ' << std::hex << *(int*)&viewport_height << '\n';
-    float viewport_width = aspect_ratio * viewport_height;
-//?     std::cerr << "viewport width: " << viewport_width << ' ' << std::hex << *(int*)&viewport_width << '\n';
-    float focal_length = 1.0;
-
-    auto origin = point3(0, 0, 0);
-    auto horizontal = vec3(viewport_width, 0, 0);
-    auto vertical = vec3(0, viewport_height, 0);
-    auto lower_left_corner = origin - horizontal/2 - vertical/2 - vec3(0, 0, focal_length);
-
-    // Render
-
-    std::cout << "P3\n" << image_width << " " << image_height << "\n255\n";
-
-    for (int j = image_height-1; j >= 0; --j) {
-//?         std::cerr << "\rScanlines remaining: " << j << ' ' << std::flush;
-        for (int i = 0; i < image_width; ++i) {
-            auto u = float(i) / (image_width-1);
-//?             std::cerr << "u: " << u << '\n';
-            auto v = float(j) / (image_height-1);
-            ray r(origin, lower_left_corner + u*horizontal + v*vertical - origin);
-//?             std::cerr << "ray origin: " << r.orig.x() << " " << r.orig.y() << " " << r.orig.z() << '\n';
-//?             std::cerr << "ray direction: " << r.dir.x() << " " << r.dir.y() << " " << r.dir.z() << '\n';
-//?             std::cerr << "ray dir.x: " << r.dir.x() << " ";
-//?               p(std::cerr, r.dir.x());
-//?               std::cerr << '\n';
-            color pixel_color = ray_color(r);
-//?             std::cerr << "pixel color: " << pixel_color.x() << " " << pixel_color.y() << " " << pixel_color.z() << '\n';
-
-//?             std::cout << "(";
-//?               p(std::cout, pixel_color.x());
-//?               std::cout << ", ";
-//?               p(std::cout, pixel_color.y());
-//?               std::cout << ", ";
-//?               p(std::cout, pixel_color.z());
-//?               std::cout << ")\n";
-            write_color(std::cout, pixel_color);
-//?             break;
-        }
-//?         break;
-    }
-
-//?     std::cerr << "\r";
-}