Kevin Watkins - MrKWatkins

Evaluating Poker Hands

Using our set of cards and our bit representations we can now evaluate poker hands using excessive bit twiddling. The general approach is to shuffle the bits for each suit around and combine them with various logical operations to work out what hand we have. We will work with bit

Poker

More Bit Representations

Card Bit Mask We already have one representation of cards using bit indices but there is another representation we could use that would be easier to work with when evaluating poker hands. A long can be split into 4 × 16 bit sections, each of which can represent a suit. 16

Poker

Card Combinations

Before we can start evaluating five card poker hands we actually need to get some five card poker hands. So we need some code to produce five card hand combinations from a full deck of cards. Combinations can be built recursively. Start with an empty combination and add cards from

Poker

A Set of Cards

Many years ago I worked at a company that used a C library for evaluating poker hands. Never really understood how it worked; it used a lot of hard to read bit twiddling. A few years back I decided to see if I could come up with something similar in

Rendering

Spherical Lights

As mentioned in the previous post I've decided to start looking at rendering again to help me learn a new programming language, Rust. I initially started with just point light sources but I have recently added spherical light sources too. Why bother? What is the difference? Point vs. Spherical Lights

Rendering

Rust Rendering

I've decided to start looking at rendering again to help me learn a new programming language, Rust. I haven't learnt a new language for a while and Rust sounds like a good one to learn. It has some nice concepts, especially around enforcing lifetimes, that I've been wanting from a

Algorithms

Topological Ordering

Topological ordering is ordering dependent items in such a way that items you depend upon come first in the ordering. For example if x depends on y and y depends on z then the topological order would be z, y, x. Maybe dependency ordering would be a better name; it

Oakley

Installing Z88DK on Ubuntu 18.04

I had a few issues whilst following the instructions to install Z88DK on Ubuntu 18.04 so thought I would document my solutions here in case anyone else has similar problems. Note that I am a Linux novice so apologies if any of this seems obvious for a Linux pro.

Oakley

Oakley - LoRes Demos

I've been adding some support to the Oakley standard library for the LoRes screen mode of the ZX Spectrum Next, as well as some code for creating palettes and floating point number support. I've created two demos that use the new code: Stripes Displays some stripes. 'nuff said. The demo

Oakley

Oakley Progress Report

I've made quite a bit of progress since I last blogged about Oakley. I might actually be able to release an alpha version in the next decade! Better Numbers * No need to specify the type of number anymore, e.g. you can now write 12 rather than 12b. * Binary literals,

ZX Spectrum Next

ZX Spectrum Next Test Programs

Whilst developing the second Oakley demo I've hit various behavioural differences between CSpect, ZEsarUX and the real hardware. I thought it might be useful to setup a repository of test programs to reproduce these differences in test cases, as opposed to just moaning about things. (Although I do enjoy moaning.

Oakley

Oakley - The Second Demo

Time for another demo created with my new programming language for the ZX Spectrum Next. This one has quite a lot more going on than the first demo and if nothing else demonstrates that I'm not completely wasting my time with this project. Here is a video of it running

Oakley

Performance Tuning Oakley

I've nearly completed the second Oakley demo and by and large it runs very well in CSpect. However there are a few minor display issues at the top of the screen which is due to the code for each frame taking slightly longer than a frame to run, meaning the

Oakley

Having Greys Makes a Bit of Difference

The ZX Spectrum Next uses 9-bits for its colours, giving a total of 512 possible different colours. The Next's palettes are only 256 colours in size however. The default palette uses 8-bit colours of the format RRRGGGBB, generated by the taking the numbers 0 - 255 in order. The third

Oakley

Keeping Things Consistent

The main rule I've tried to follow when designing Oakley is to avoid special cases as far as possible. C# has quite a few of these and they annoy me. For example: * Constructors. Why do these have a special syntax? They're just a static function that returns a value. There

Oakley

Oakley - The First Demo

I've managed to get my new programming language to a state where I can release a demo that is vaguely interesting. Here is a video of the demo running on the CSpect emulator: Yes, it's a bouncy snake thing. Here is the Oakley source code: using System; using System.Maths;

Oakley

Oakley - Writing a New Language

After many years of moaning about various other languages I've decided to try and write my own, if only so I don't have to listen to myself moan about such things any more... The idea to do so originally came from the Facebook group for the ZX Spectrum Next, a

Rendering

Triangles and Meshes

Next step is to add in triangles. From there we can go to meshes of triangles, and then render something a bit more interesting than a sphere... Triangles As with previous shapes to render a triangle we need to be able to calculate if a ray intersects it or not.

Rendering

Transparent Boxes

Transparency. This is similar to reflection, however instead of tracing a reflected ray away from the object we trace a transmitted ray into the object. Transmittance I accidentally added transmittance to the ray tracer when developing reflections; instead of using the reflected direction for the reflected ray I accidentally used

Rendering

Phong and Reflections

Next up is improving the shading model and adding reflections. Phong Reflection Model The Phong reflection model adds to Lambertian reflectance with a term for specular highlights, the sharp highlights you see on shiny surfaces. The equation for Phong reflectance is: \[ C = k_A C_A + \sum_{i} (k_D

Rendering

Attenuation, Textures and Third Party Code

To make the scenes a bit more interesting the next step is to add some more realistic lighting and some textures. Attenuation When modelling Lambertian Reflectance I made the lights have constant intensity, i.e. the intensity at the point on the surface \( I \) was always 1. In reality the

Rendering

Plane Shading

To make things look a bit more 3D we need to have a more realistic shading model and add some lights. Types for Lighting Let's add some more types: * Light. Base class for all types of light. Stores the colour of the light (I'm not doing anything more complicated for

Rendering

First Image

Now we have an framework in place we can start on the ray tracing itself. Types for Geometry First step is to add some types to handle geometry: * Point. Represents a point in three dimensions. * Vector. Represents a vector in three dimensions. Although very similar to a point as both

Rendering

Basic Framework

First step was to get a basic framework in place that can render an image and preview it in the GUI. I added a separate project for all the rendering code, keeping all the display stuff in the GUI project. Helps separate concerns and will make it easier to, for

Rendering

I've decided I need a pet project to practice my coding and to help me (finally!) learn C++. I've been interested in ray tracing for years now, ever since I got my hands on a copy of Imagine for my Amiga 1200. So my initial idea was to create a