JiayinCao

/*
    MIT License

    Copyright (c) 2023 Jiayin Cao

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is

mmozeiko

#pragma once

// uncompressed png writer & reader
// supports only 8-bit and 16-bit formats

// Performance comparison for 8192x8192 BGRA8 image (256MB)
// Compiled with "clang -O2", AVX2 requires extra "-mavx2" or "/arch:AVX2" argument
//
// For libpng (compressed) uses default libpng/zlib compression settings
// For libpng (uncompressed) case following two functions are used:

d7samurai

Minimal D3D11 bonus material: pixel art antialiasing

A minimal Direct3D 11 implementation of "antialiased point sampling", useful for smooth fractional movement and non-integer scaling of pixel art AKA "fat pixel" aesthetics.

Also view below side-by-side point sampling comparison on YouTube (video is zoomed in to counter implicit downsampling & compression artifacts and make aa effect more apparent) or check out the Shadertoy.

The actual sampler is set to bilinear filtering (the default D3D11 sampler state) in order to utilize single texture-read hardware interpolation, then emulating point sampling in the shader and applying AA at the fat pixel boundaries. Use with premultiplied alpha textures* and keep a one pixel transparent border around each sprite/tile.

vassvik

Realtime Fluid Simulation: Projection

The core of most real-time fluid simulators, like the one in EmberGen, are based on the "Stable Fluids" algorithm by Jos Stam, which to my knowledge was first presented at SIGGRAPH '99. This is a post about one part of this algorithm that's often underestimated: Projection

MG4_F32.mp4

Stable Fluids

The Stable Fluids algorithm solves a subset of the famous "Navier Stokes equations", which describe how fluids interact and move. In particular, it typically solves what's called the "incompressible Euler equations", where viscous forces are often ignored.

d7samurai

Minimal D3D11 pt2

Follow-up to Minimal D3D11, adding instanced rendering. As before: An uncluttered Direct3D 11 setup & basic rendering primer / API familiarizer. Complete, runnable Windows application contained in a single function and laid out in a linear, step-by-step fashion. No modern C++ / OOP / obscuring cruft.

The main difference here is that the hollow cube is rendered using DrawIndexedInstanced (which saves a lot of vertices compared to the original, so model data is now small enough to be included in the source without being too much in the way), but also all trigonometry and matrix math is moved to the vertex shader, further simplifying the main code.

Each instance is merely this piece of geometry, consisting of 4 triangles:

..which is th

ibireme

// =============================================================================
// XNU kperf/kpc demo
// Available for 64-bit Intel/Apple Silicon, macOS/iOS, with root privileges
//
//
// Demo 1 (profile a function in current thread):
// 1. Open directory '/usr/share/kpep/', find your CPU PMC database.
//    M1 (Pro/Max/Ultra): /usr/share/kpep/a14.plist
//    M2 (Pro/Max):       /usr/share/kpep/a15.plist
//    M3:                 /usr/share/kpep/as1.plist

pervognsen

// Estimating CPU frequency...
// CPU frequency: 4.52 GHz
// sum1: value = 15182118497126522709, 0.31 secs, 5.14 cycles/elem
// sum2: value = 15182118497126522709, 0.17 secs, 2.93 cycles/elem

#define RW(x) asm("" : "+r"(x))

typedef struct Node {
	u64 value;
	struct Node *next;

pervognsen

A traditional table-based DFA implementation looks like this:

uint8_t table[NUM_STATES][256]

uint8_t run(const uint8_t *start, const uint8_t *end, uint8_t state) {
    for (const uint8_t *s = start; s != end; s++)
        state = table[state][*s];
    return state;
}

NoelFB

#pragma once

namespace YourNamespace
{
	struct Routine
	{
        // Current "waiting time" before we run the next block
        float wait_for = 0;

        // Used during `rt_for`, which repeats the given block for X time

ityonemo

A half-hour to learn Zig

This is inspired by https://fasterthanli.me/blog/2020/a-half-hour-to-learn-rust/

Basics

the command zig run my_code.zig will compile and immediately run your Zig program. Each of these cells contains a zig program that you can try to run (some of them contain compile-time errors that you can comment out to play with)