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Graphics Programming Weekly

jendrikillner.com

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Re: Graphics Programming Weekly

#11

Post by jak6jak »

theschwa wrote: post #6
jak6jak wrote: post #2

I’ve always wanted to get into graphical programming but I always get hung up on creating anything. Shaders feel like black magic to me. And the tutorials are spread across many different technologies and techniques that it’s hard to determine where you should start.

Graphical programming is a blast. I can totally see how it feels overwhelming, especially with a lot of ways to do the same thing. I will say though that once you get started a lot of the knowledge is transferable to different technologies and methods. I tend to recommend that people start with The Book of Shaders [0]. What kinds of things would you ultimately like to make? [0] - https://thebookofshaders.com/

I tried the book of shaders but I think I got stuck when it got into the algorithmic drawing. I kept on getting confused on each individual line and how it fit into creating the whole picture especially when smoothstep() is involved. As for what I want to make, nothing in particular right now my end goal is perhaps to get a job as a graphical programmer somewhere.

Re: Graphics Programming Weekly

#12

Post by Arelius »

jak6jak wrote: post #2

I’ve always wanted to get into graphical programming but I always get hung up on creating anything. Shaders feel like black magic to me. And the tutorials are spread across many different technologies and techniques that it’s hard to determine where you should start.

I mean they are a bit. They are programs that fit pretty arbitrarily into other parts of the rendering pipeline. I recommend starting with Compute Shaders as those end up being just a big parallel map on your dispatch size. A lot less pipeline to understand.

The other key thing to understand, is that a GPU is across a network (PCI-X network generally) So when you call dispatch, your generally sending a message (encoding a command in a command buffer) to do the work later on on a different device.

Re: Graphics Programming Weekly

#13

Post by soylentgraham »

jak6jak wrote: post #2

I’ve always wanted to get into graphical programming but I always get hung up on creating anything. Shaders feel like black magic to me. And the tutorials are spread across many different technologies and techniques that it’s hard to determine where you should start.

What do you want to make!

Starting with a software renderer is nuts.

Start with unity, make an unlit shader, start doing basic effects (in colours, then using texture samples) using uv coordinates. (In frag, ignore vertexes to start with). Just remember youre just colouring a pixel, on a bit of a surface.

Re: Graphics Programming Weekly

#14

Post by Arelius »

Arelius wrote: post #12
jak6jak wrote: post #2

I’ve always wanted to get into graphical programming but I always get hung up on creating anything. Shaders feel like black magic to me. And the tutorials are spread across many different technologies and techniques that it’s hard to determine where you should start.

I mean they are a bit. They are programs that fit pretty arbitrarily into other parts of the rendering pipeline. I recommend starting with Compute Shaders as those end up being just a big parallel map on your dispatch size. A lot less pipeline to understand. The other key thing to understand, is that a GPU is across a network (PCI-X network generally) So when you call dispatch, your generally sending a message (encod…

> cmdList->Dispatch(dispatchSize/64, 1, 1);

> [numthreads(64, 1, 1)] > void main(uint3 threadIdx : SV_DispatchThreadID) {

the dispatch size (x, y, and z) are multiplied by the numthreads components (Some compiler SIMD stuff requires this) And that sum total threads (x * y * z) are launched. the index of the thread this particular invocation is launched on is left in threadIdx, you can then use that index to read and write from other buffers.

This is HLSL, but the same generally applies to most APIs. Then more of this just becomes implicit and behind the scenes for shaders dispatched in other contexts, since more is known implicitly about the context, and more is done by other units of the hardware.

Re: Graphics Programming Weekly

#15

Post by theschwa »

jak6jak wrote: post #11
theschwa wrote: post #6

Earlier quoted context omitted.

Graphical programming is a blast. I can totally see how it feels overwhelming, especially with a lot of ways to do the same thing. I will say though that once you get started a lot of the knowledge is transferable to different technologies and methods. I tend to recommend that people start with The Book of Shaders [0]. What kinds of things would you ultimately like to make? [0] - https://thebookofshaders.com/

I tried the book of shaders but I think I got stuck when it got into the algorithmic drawing. I kept on getting confused on each individual line and how it fit into creating the whole picture especially when smoothstep() is involved. As for what I want to make, nothing in particular right now my end goal is perhaps to get a job as a graphical programmer somewhere.

Yeah, that makes sense. There's some mental gymnastics involved in writing shaders since you're writing the code from the perspective of an individual pixel. As opposed to other methods like using Processing or the HTML canvas where you can just say "draw a square from here to here and make the lines this thick". When writing a shader, I have think instead "Ok, if I want a line here, and I was a pixel on that line, what would I need to know to determine my color".

If you're finding that to be the obstacle with shaders, it may be helpful to start with just learning a library like Processing, or general graphics library in whatever programming language you're comfortable with, and then come back to shaders. It will still take changing how you think about things, but then you'll have some solid foundation.

Personally, I've found it the most helpful to have some kind of goal in mind. Some kind of image or style that I want to make, then figure out what techniques I need to learn to get there. Starting from the technical side can work, but then it can be easier to loose interest when things get challenging. When I start with an artistic vision, then I often find myself over my head in the technical things I need to learn, but I feel motivated to push through that to get to the end goal.

Re: Graphics Programming Weekly

#16

Post by d26900 »

soylentgraham wrote: post #13
jak6jak wrote: post #2

I’ve always wanted to get into graphical programming but I always get hung up on creating anything. Shaders feel like black magic to me. And the tutorials are spread across many different technologies and techniques that it’s hard to determine where you should start.

What do you want to make! Starting with a software renderer is nuts. Start with unity, make an unlit shader, start doing basic effects (in colours, then using texture samples) using uv coordinates. (In frag, ignore vertexes to start with). Just remember youre just colouring a pixel, on a bit of a surface.

> Starting with a software renderer is nuts.

No, not really. You can write a simplistic ray tracer and rasterizer in about 10 - 50 lines tops:

https://github.com/d26900/JamaisVu/blob/main/tests.c

Lines 66 - 91.

The result/screenshot: https://github.com/d26900/JamaisVu

If this is "nuts", then so be it. Let me be nuts. :P

Re: Graphics Programming Weekly

#18

Post by kemiller2002 »

ggambetta wrote: post #4
jak6jak wrote: post #2

I’ve always wanted to get into graphical programming but I always get hung up on creating anything. Shaders feel like black magic to me. And the tutorials are spread across many different technologies and techniques that it’s hard to determine where you should start.

May I suggest my book? The full contents are online: https://gabrielgambetta.com/computer-graphics-from-scratch/

And here I was hoping this was going to be a worthwhile link to check....except i’ve already bought that one :p.

In all seriousness. It sounds like a cool book. Can’t wait til it arrives. Thanks for writing it!

Re: Graphics Programming Weekly

#19

Post by ggambetta »

jak6jak wrote: post #9
ggambetta wrote: post #4

Earlier quoted context omitted.

May I suggest my book? The full contents are online: https://gabrielgambetta.com/computer-graphics-from-scratch/

I saw that book but was confused on the way to use it. Are you supposed to follow along and turn the pseudo code into a real implementation? Or is meant to be Passively read while perhaps taking notes?

I guess that's up to you. Both work, although it's probably best if you follow along and implement the raytracer and the rasterizer as you go.

Re: Graphics Programming Weekly

#20

Post by tpmx »

jak6jak wrote: post #2

I’ve always wanted to get into graphical programming but I always get hung up on creating anything. Shaders feel like black magic to me. And the tutorials are spread across many different technologies and techniques that it’s hard to determine where you should start.

A very general piece of advice:

Try to find a small and unusually talented team doing what you want to learn, and get hired by them. There is no substitute to learning from smart/experienced people.

(This is after learning the basics + the intermediate stuff.)

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