ggambetta / computer-graphics-from-scratch Goto Github PK

In the section Subtractive color model, at the CMYK color model drawing, it should be:
magenta+cyan=blue
magenta+yellow=red

Great book!

As we want to optimize performance, using any triangle vertex instead of the center seems more desirable. Moreover, using a triangle vertex is more in line with the description in the book and less confusion.

Incidentally, if we wrote

It seems to be simply uninplemented

In both the chapter on specular reflection (Raytracing, Light) and Phong shading (Rasterization, Shading), you apply the specular intensity to the object color to get the final color.

However, specular intensity is usually applied to the light color (and lights are usually white, which is why specular highlights are usually white) and added to the diffuse color to get the final color, as quite nicely visually illustrated on the wikipedia page for Phong Shading.

I assume that this might have been a simplification done for educational reasons, but it does mean the shading model you describe in the Phong Shading chapter isn't actually using the Phong reflection model.

I would suggest changing things around to do it the more common way (the changes for the raytracer aren't too bad, but I admit haven't worked through the rasterizer yet), but if you feel this would complicate the code or explanation too much, perhaps just don't call the shading model "Phong".

While kinda obvious, the fact that background color is changed to black isn't mentioned explicitly.

I read much better in an e-reader than on screens.

There does not appear to be any license information in the repo as a whole or in the text of the book.

Please add a license or public domain release (eg: CC0, Unlicense, etc) when you get the chance. Some sort of public domain option seems simplest, since the book is free anyway.

The content seems to be super interesting. However it's not in the most reader-friendly format (IMO). Have you considered something like:

• GitBook
• LeanPub

I'm not in any way affiliated (nor have been) with either. I know GitBook does have a free tier (0 private books, 0 collaborators).

Hello, I noticed the wrong behavior in directional lighting.

My scene in pseudocode:

light {
    type = directional
    intensity = 1
    direction = (0, 0, 1)
}

sphere {
    center = (0, -1, 3)
    radius = 1
    color = (255, 0, 0) 
}
sphere {
    center = (2, 0, 4)
    radius = 1
    color = (0, 0, 255) 
}
sphere {
    center = (-2, 0, 4)
    radius = 1
    color = (0, 255, 0) 
}

I get a scene like this:

Hi,

Firstable, thank you for this very precise tutorial.

I may be wrong because this is the first time I m doing this kind of maths, but would not be more accurate to say that vector CO = O−C instead of vector OC = O−C ? (Cf. chapter "Basic ray tracing", title "Rays meet sphere") ?

In the Basic ray tracing chapter.

In general, using a 60 FOV in the horizontal and vertical directions produces reasonable images; this is achieved with Vw = Vh = d = 1.

here if the FOV is 60, d should not equal 1. draw the triangle.

A great book, thanks for sharing.

var viewport_size = 1;
var projection_plane_z = 1;

it contradicts with

var s2 = 1.0 / Math.sqrt(2);
camera.clipping_planes = [
  Plane(Vertex(0, 0, 1), -1), // Near
  Plane(Vertex(s2, 0, s2), 0), // Left
  Plane(Vertex(-s2, 0, s2), 0), // Right
  Plane(Vertex(0, -s2, s2), 0), // Top
  Plane(Vertex(0, s2, s2), 0), // Bottom
];

The text points 1/sqrt(2) as a constant that repeats on most clipping plane normals:

However the code uses sqrt(2) instead:

Is that correct?

Viewport seems to be a larger canvas. Do they have the same z-axis value?

I am using the Google Chrome browser to read the chapters. I have no installed extensions that would affect the loading of the figures. This is what I see right now:

Are the chapters still a work in progress? If so, please ignore this issue. I can close it.

I was considering proof reading some of the text and making a pull request, but the text doesn't appear to be in the repository... Unless I'm going blind haha.