54 lines
1.5 KiB
Zig
54 lines
1.5 KiB
Zig
const std = @import("std");
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const math = std.math;
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const Point3 = @import("vec3.zig").Point3;
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const Vec3 = @import("vec3.zig").Vec3;
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const Ray = @import("ray.zig").Ray;
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fn degreesToRadians(degrees: f32) f32 {
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return degrees * math.pi / 180.0;
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}
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pub const Camera = struct {
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origin: Point3,
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lowerLeftCorner: Point3,
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horizontal: Vec3,
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vertical: Vec3,
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pub fn init(
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lookFrom: Point3,
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lookAt: Point3,
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vup: Vec3,
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vfov: f32,
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aspectRatio: f32,
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) Camera {
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const theta = degreesToRadians(vfov);
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const h = math.tan(theta / 2);
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const viewportHeight = 2.0 * h;
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const viewportWidth = aspectRatio * viewportHeight;
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const w = lookFrom.sub(lookAt).unit();
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const u = vup.cross(w).unit();
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const v = w.cross(u);
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const origin = lookFrom;
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const horizontal = u.mul_s(viewportWidth);
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const vertical = v.mul_s(viewportHeight);
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const lowerLeftCorner = origin.sub(horizontal.div(2)).sub(vertical.div(2)).sub(w);
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return Camera {
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.origin = origin,
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.horizontal = horizontal,
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.vertical = vertical,
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.lowerLeftCorner = lowerLeftCorner,
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};
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}
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pub fn getRay(self: Camera, s: f32, t: f32) Ray {
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return Ray{
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.origin = self.origin,
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.direction = self.lowerLeftCorner.add(self.horizontal.mul_s(s)).add(self.vertical.mul_s(t)).sub(self.origin),
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};
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}
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}; |