setup random world

in_one_weekend/src/main.zig

@@ -76,6 +76,94 @@ fn setProgress(surface: *sdl.c.SDL_Surface, width: usize, height: usize, percent
     }
 }
 
+fn setupWorld(world: *World, rng: *Random) !void {
+    try world.spheres.append(Sphere{
+        .center = Point3{ .x = 0, .y = -1000, .z = 0 },
+        .radius = 1000,
+        .material = Material{ .lambertian = material.Lambertian{
+            .color = Color{ .x = 0.5, .y = 0.5, .z = 0.5 }
+        }}
+    });
+
+    var a: f32 = -11;
+    while (a < 11) : (a += 1) {
+        var b: f32 = -11;
+        while (b < 11) : (b += 1) {
+            const chooseMat = rng.float(f32);
+            const center = Point3{
+                .x = a + 0.9 * rng.float(f32),
+                .y = 0.2,
+                .z = b + 0.9 * rng.float(f32),
+            };
+
+            if (center.sub(Point3{ .x = 4, .y = 0.2 }).length() > 0.9) {
+                if (chooseMat < 0.8) {
+                    // diffuse
+                    try world.spheres.append(Sphere{
+                        .center = center,
+                        .radius = 0.2,
+                        .material = Material{ .lambertian = material.Lambertian{
+                            .color = Color{
+                                .x = rng.float(f32) * rng.float(f32),
+                                .y = rng.float(f32) * rng.float(f32),
+                                .z = rng.float(f32) * rng.float(f32),
+                            }
+                        }},
+                    });
+                } else if (chooseMat < 0.95) {
+                    // metal
+                    try world.spheres.append(Sphere{
+                        .center = center,
+                        .radius = 0.2,
+                        .material = Material{ .metal = material.Metal{
+                            .color = Color{
+                                .x = 0.5 + rng.float(f32) / 2,
+                                .y = 0.5 + rng.float(f32) / 2,
+                                .z = 0.5 + rng.float(f32) / 2,
+                            },
+                            .fuzz = rng.float(f32) / 2,
+                        }},
+                    });
+                } else {
+                    // glass
+                    try world.spheres.append(Sphere{
+                        .center = center,
+                        .radius = 0.2,
+                        .material = Material{ .dielectric = material.Dielectric{
+                            .refraction_index = 1.5,
+                        }},
+                    });
+                }
+            }
+        }
+    }
+
+    try world.spheres.append(Sphere{
+        .center = Point3{ .x = 0, .y = 1, .z = 0 },
+        .radius = 1,
+        .material = Material{ .dielectric = material.Dielectric{
+            .refraction_index = 1.5
+        }},
+    });
+
+    try world.spheres.append(Sphere{
+        .center = Point3{ .x = -4, .y = 1, .z = 0 },
+        .radius = 1,
+        .material = Material{ .lambertian = material.Lambertian{
+            .color = Color{ .x = 0.4, .y = 0.2, .z = 0.1 }
+        }},
+    });
+
+    try world.spheres.append(Sphere{
+        .center = Point3{ .x = 4, .y = 1, .z = 0 },
+        .radius = 1,
+        .material = Material{ .metal = material.Metal{
+            .color = Color{ .x = 0.7, .y = 0.6, .z = 0.5 },
+            .fuzz = 0.0
+        }},
+    });
+}
+
 pub fn main() anyerror!void {
     if (sdl.c.SDL_Init(sdl.c.SDL_INIT_VIDEO) != 0) {
         std.log.err("Unable to initialize SDL: {}", .{sdl.c.SDL_GetError()});
@@ -83,6 +171,9 @@ pub fn main() anyerror!void {
     }
     defer sdl.c.SDL_Quit();
 
+    var prng = std.rand.DefaultPrng.init(42);
+
+
     // Image
     const aspectRatio: f32 = 16.0 / 9.0;
     const imageWidth = 600;
@@ -91,43 +182,16 @@ pub fn main() anyerror!void {
     const maxDepth = 50;
 
     // World
-    const materialGround = Material{
+    var world = World.init();
-        .lambertian = material.Lambertian{
+    defer world.deinit();
-            .color = Color{ .x = 0.8, .y = 0.8, .z = 0.0 },
+    try setupWorld(&world, &prng.random);
-        }
-    };
-    const materialCenter = Material{
-        .lambertian = material.Lambertian{
-            .color = Color{ .x = 0.1, .y = 0.2, .z = 0.5 },
-        }
-    };
-    const materialLeft = Material{
-        .dielectric = material.Dielectric{
-            .refraction_index = 1.5,
-        }
-    };
-    const materialRight = Material{
-        .metal = material.Metal{
-            .color = Color{ .x = 0.8, .y = 0.6, .z = 0.2 },
-            .fuzz = 1.0,
-        }
-    };
-
-    const spheres = [_]Sphere{
-        Sphere{ .center = Point3{ .x = 0, .y = -100.5, .z = -1 }, .radius = 100, .material = materialGround },
-        Sphere{ .center = Point3{ .x = 0, .y = 0, .z = -1 }, .radius = 0.5, .material = materialCenter },
-        Sphere{ .center = Point3{ .x = -1, .y = 0, .z = -1 }, .radius = 0.5, .material = materialLeft },
-        Sphere{ .center = Point3{ .x = -1, .y = 0, .z = -1 }, .radius = -0.45, .material = materialLeft },
-        Sphere{ .center = Point3{ .x = 1, .y = 0, .z = -1 }, .radius = 0.5, .material = materialRight },
-     };
-    const world = World{ .spheres = spheres[0..spheres.len] };
 
     // Camera
-    const lookFrom = Point3{ .x = 3, .y = 3, .z = 2 };
+    const lookFrom = Point3{ .x = 13, .y = 2, .z = 3 };
-    const lookAt = Point3{ .x = 0, .y = 0, .z = -1 };
+    const lookAt = Point3{ .x = 0, .y = 0, .z = 0 };
     const vup = Vec3{ .x = 0, .y = 1, .z = 0 };
-    const distToFocus = lookFrom.sub(lookAt).length();
+    const distToFocus = 10;
-    const aperture = 2.0;
+    const aperture = 0.1;
     const camera = Camera.init(
         lookFrom,
         lookAt,
@@ -155,7 +219,6 @@ pub fn main() anyerror!void {
         return error.SDLInitializationFailed;
     };
 
-    var prng = std.rand.DefaultPrng.init(42);
     var pixelAccu: [imageWidth * imageHeight]Color = undefined;
     for (pixelAccu) |*pixel| {
         pixel.* = Color{};

in_one_weekend/src/world.zig

@@ -1,15 +1,28 @@
+const std = @import("std");
+const ArrayList = std.ArrayList;
+
 const Sphere = @import("sphere.zig").Sphere;
 const HitRecord = @import("hittable.zig").HitRecord;
 const Ray = @import("ray.zig").Ray;
 
 pub const World = struct {
-    spheres: []const Sphere,
+    spheres: ArrayList(Sphere),
 
-    pub fn hit(self: World, ray: Ray, t_min: f32, t_max: f32) ?HitRecord {
+    pub fn init() World {
+        return World {
+            .spheres = ArrayList(Sphere).init(std.testing.allocator)
+        };
+    }
+
+    pub fn deinit(self: *World) void {
+        self.spheres.deinit();
+    }
+
+    pub fn hit(self: *const World, ray: Ray, t_min: f32, t_max: f32) ?HitRecord {
         var hitRecord: ?HitRecord = null;
         var closest = t_max;
 
-        for (self.spheres) |sphere| {
+        for (self.spheres.items) |sphere| {
             if (sphere.hit(ray, t_min, closest)) |localHit| {
                 closest = localHit.t;
                 hitRecord = localHit;