ray-tracing

Class Diagrams

---
title: Tuple, Vector and Pointer
---
classDiagram
    note "Legend:
    + Public
    - Private
    # Protected
    ~ Package/Internal
    $ Static
    * Abstract
    <|--	Inheritance
    *--	Composition
    o--	Aggregation
    -->	Association
    --	Link (Solid)
    ..>	Dependency
    ..|>	Realization
    ..	Link (Dashed)"

    class Tuple{
        +float x
        +float y
        +float z
        +float w
        +Add()
        +Negate()
    }

%%    note for Vector "Note: w is 0"
    Tuple --|> Vector : Inheritance
    class Vector{
        float w$=0
        -Dot()
        -Cros()
    }

%%    note for Pointer "Note: w is 1"
    Tuple --|> Point : Inheritance
    class Point{
        float w$=1
    }

Chapter 1

Add

• Vector + Vector => Vector
• Vector + Point => Point
• NO ALLOWED: Point + Point => (w=2)

Subtract

• Vector - Vector => Vector
• Point - Vector => Point
• NOT ALLOWED: Vector - Point => (w=-1)

Negate

• (x, y, z, w) => (-x, -y, -z, -w)

Scalar Operations

• s * (x, y, z, w) => (sx, sy, sz, sw)
• (x, y, z, w) / s => (x/s, y/s, z/s, w/s)

Magnitude

• |v| = sqrt(x^2, y^2, z^2, w^2), where w = 0, i.e. vector

Normalization

• (x/|v|, y/|v|, z|v|, w/|v|)

Dot Product

• (vector1, vector2) => scalar, i.e. x1 * x2 + y1y2 + z1z2 + w1*w2

Cross Product

• (vector1, vector2) => (vector3)
• i.e. (a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x)

Test Frameworks

Ginkgo

Bootstrapping a Suite

Generate a new test suite in the current directory:

cd path/to/books
ginkgo bootstrap

Running Tests

• Run the tests in the current directory:

ginkgo

• Run all tests for the project:

go run github.com/onsi/ginkgo/v2/ginkgo -r --randomize-all --randomize-suites --fail-on-pending --keep-going --cover --coverprofile=cover.profile --race --trace --json-report=report.jso

Adding Specs to a Suite

This will generate a test file named book_test.go in the books directory:

```shell
ginkgo generate book