kevinmoran

How to Calculate a Rotation Matrix to Align Vector A to Vector B in 3D

Based on 'Avoiding Trigonometry' by Íñigo Quílez

Expanded derivation by Kevin - 29/11/18

Introduction

Original article: https://iquilezles.org/www/articles/noacos/noacos.htm

kevinmoran

// From: https://web.archive.org/web/20080228213915/http://www.devmaster.net/forums/showthread.php?t=5784

float sinApprox(float x)
{
    const float kPI32 = 3.14159265359f;
    const float B = 4/kPI32;
    const float C = -4/(kPI32*kPI32);

    float y = B * x + C * x * abs(x);

kevinmoran

// Source: https://www.youtube.com/watch?v=1xlCVBIF_ig

float cubicSinf(float x)
{
  float t = x * 0.15915f;
  t = t - (int)t;
  return 20.785f * t * (t - 0.5f) * (t - 1.f);
}

kevinmoran

#include <windows.h>
#include <mmdeviceapi.h>
#include <audioclient.h>

#include <assert.h>
#define _USE_MATH_DEFINES
#include <math.h> // for sin()
#include <stdint.h>

kevinmoran

// Simple example code to load a Wav file and play it with WASAPI
// This is NOT complete Wav loading code. It is a barebones example 
// that makes a lot of assumptions, see the assert() calls for details
//
// References: 
// http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
// Handmade Hero Day 138: Loading WAV Files

#include <windows.h>

kevinmoran

// Minimal Murmur3 implementation shared by Demetri Spanos on Handmade Network Discord
//
// Code is deliberately terse and simplistic
// Intended to be the first hash function you reach for e.g. a simple hash table
// *** NB THIS IS NOT A CRYPTOGRAPHIC HASH ***
//
// @demetrispanos:
// "yes let me reiterate the moral of this story
// there is never any reason to use a dumb made up hash function
// use murmur3 or jenkins-one-at-a-time for a 0-effort version

kevinmoran

• The Perils of Future-Coding - Sebastian Sylvan
• John Carmack on Inlined Code
• CppCon 2014: Mike Acton "Data-Oriented Design and C++"
• Semantic Compression - Casey Muratori
• Learning From Failure - Alex Evans. Talk about the long development of Media Molecule's Dreams.
• Thirteen Years of Bad Game Code - Evan Todd
• Memory Allocation Strategies blog series
• The Mundanity of Excellence - Daniel F. Chambliss. Really accessible academic paper on how people achieve excellence, literally everyone on earth should read this.
• [Mike

kevinmoran

• encoding: http://www.unicode.org/versions/Unicode13.0.0/
• shaping: https://harfbuzz.github.io/
• font file format: https://docs.microsoft.com/en-us/typography/opentype/spec/
• rasterization:
  • https://nothings.org/gamedev/rasterize/
  • http://rastertragedy.com/
  • https://www.grc.com/cleartype.htm
  • https://www.freetype.org/freetype2/docs/text-rendering-general.html
  • Rendering Resolution Independent Fonts in Games and 3D Applications (Master's Thesis - Olle Alvin): https://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=9024910&fileOId=9024911
• Adventures in Text Rendering: Kerning and Glyph Atlases: https://www.warp.dev/blog/adventures-text-rendering-kerning-glyph-atlases

kevinmoran

enum EntityProperty
{
  EntityProperty_IsActive,
  EntityProperty_RenderModel,
  EntityProperty_Hostile,
  EntityProperty_OnFire,
  EntityProperty_SomethingElse,
  EntityProperty_Count
};

kevinmoran

// Source: "xoshiro / xoroshiro generators and the PRNG shootout" 
// https://prng.di.unimi.it/

#include <stdint.h>

static inline double u64ToDoubleBetween01(uint64_t x) {
    return (x >> 11) * 0x1.0p-53;
}

// I came up with the following function for 32-bit floats based on the above, let me know if it's wrong