Nick Porcino meshula

Install development tools and SDL2

apt-get update apt-get install -y zsh git build-essential cmake
libsdl2-dev libsdl2-2.0-0
libvulkan-dev vulkan-tools
libsdl2-mixer-dev # For audio

Create our game user and directories

useradd -m -s /usr/bin/zsh game mkdir -p /opt/game/{assets,config}

What is a color space, and what is Rec709?

Illuminant E and the Spectral Locus

A long time ago before most of us were born, the science of the measurement of light had become quite advanced, sensitive instruments and clever procedures could very precisely distinguish one wavelength of light from another and could measure all the wavelengths in a spectrum. Knowledge of the eye too had advanced, and clever and precise methods relying on both instruments and people's abilities to judge what they were seeing led to quite good descriptions of how the retina, via the rods and cones, could turn a certain amount of light into a certain amount of retinal activity.

These retinal response curves led to the mathematical RGB tristimulus model we are all familiar with, each of the red, green, and blue curves corresponding very well to the response of the retina to light. Unsurprisingly, those corresponds very well also to the distribution of light in the environment, and there's good quantum mechanical reasons for

Nick Porcino has worked at the intersection of art and engineering since the first days of 8 bit computers and consoles. His early research into computer graphics, neural networks and robotics in the 1980s led to a career developing technologies for toys, game engines, film production, mobile phones, and AR/VR. He has developed and contributed to toys at Bandai, tools and engines for games and films at Disney, LucasArts, Industrial Light and Magic, and Pixar, frameworks for interactive 3d at Apple, human avatars at Oculus Research, and is now a principal engineer on Pixar’s OpenUSD team.

First, invoke hydra to render, then fetch the texture from the HdxTaskController, which is on HdEngine.

    // do the render
    _engine->Render();

    auto tc = _engine->GetHdxTaskController();
    HdRenderBuffer* buffer = tc->GetRenderOutput(HdAovTokens->color);
    buffer->Resolve();

I take a strong philosophical break with many game editors. It's considered in normal in editors that one directly manipulates the representation of objects in the scene, rather than transacting properties of the objects in the scene.

To sidebar that a bit, a really common criticism of C and C++ is the lack of reflection of structs and classes, and the large number of macro and template libraries that attempt to add it in some way are evidence that it's a common way of thinking about user facing data editing. We can also see the prevelance of systems like CapnProto, flatbuffers, protobuf, etc., that all draw a one to one correspondence between an object and its implementation.

That approach ties directly what a program does to what a program represents. It also means that a barrier to portability between systems is that instead of a system functioning, in a conceptual sense, the same as another system, it must instead to the degree necessary t

Measuring Light

Light is measured in two ways. Radiometry measures the energy impinging on a sensor, and photometry attempts to qualitatively measure light to represent how a human observer experiences light. Radiometry is important when physical metrics must be preserved, such as in simulation tasks, and photometry is important in subjective tasks, such as selecting lights to illuminate a street.

Radiometric Units

Radiometric units measure the physical properties of light, independent of human perception. These units are based on the total energy or power of light across all wavelengths.

To better understand how these radiometric units are related, imagine a conceptual "cube" where each axis represents a dimension of measurement integration:

	// ttvColor.h
	#ifndef TTVCOLOR_INCLUDED
	#define TTVCOLOR_INCLUDED

	typedef struct {
	float x, y;
	} ttvCIEXY;

	typedef struct {
	float r, g, b;

	#usda 1.0
	(
	doc = """UsdSkyModel is a schema representing procedural sky parameters.
	It allows for defining parameters like solar position, atmospheric clarity,
	and the underlying sky model (Preetham, Hosek-Wilkie, Nishita) for realistic
	sky rendering.

	UsdCloudModel is a schema for defining procedural cloud parameters,
	inspired by meteorological concepts like cloud cover, cloud types, altitude,
	and density. Multiple layers can be combined to create complex cloud formations.


	#ifndef included_noodle_h
	#define included_noodle_h

	/*
	LabNoodle

	Graphical Graph Editor

	The interface does not expose the UI system, but currently the

	#usda 1.0
	(
	endTimeCode = 241
	framesPerSecond = 24
	metersPerUnit = 1
	startTimeCode = 101
	timeCodesPerSecond = 24
	upAxis = "Y"
	)