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Eric Lengyel

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  1. Eric Lengyel

    Font rendering

    Yeah, and since that's not a sustainable business model, we are unable to provide such a cheap option. Top-of-the-line professional-quality software costs money, and if an indie team can't afford it, they'll just have to settle for something that's not as good until they've grown bigger. There's nothing stopping you from negotiating a licensing deal up front so you'd know exactly what you'd have to pay if and when your product ships.
  2. Eric Lengyel

    Font rendering

    What would you consider "cheap" for an indie commercial product? (The library is already free for noncommercial use.)
  3. Eric Lengyel

    Font rendering

    Back in December, I started playing around with new font rendering techniques, and I ran into some serious numerical robustness issues with the above method. You can see some of the problems in this Twitter thread: I spent about a month full-time trying to make it work, but failed over and over. I could fix some artifacts, but doing so would always introduce others. There is simply no way to make this approach work cleanly for all fonts, sizes, etc., due to the finite precision of floating-point operations and the manner in which the technique determines whether a pixel is inside the glyph or not. So I started doing some R&D and came up with a new method that I've now turned into this product: http://sluglibrary.com/ It is 100% robust for all possible inputs, it's about 8 times faster than the above method, and it doesn't have the glyph complexity limits that the above method has. To my knowledge, this is the only production-ready solution for rendering text directly from glyph outlines, and it has arrived right as GPUs are becoming powerful enough to justify it and right as higher-DPI displays are becoming common enough to create a need for it. And there's even a conversion tool so you can try out any TTF font.
  4. Eric Lengyel

    Normal Vector Transformation

      Thanks for the mention. My book goes into much more detail about all of this: https://www.amazon.com/dp/0985811749/?tag=terathon-20
  5.   Could you please stop using a pirated copy of my book? Moderator, can you please remove the link?
  6.   Very cheap. Only about two dozen scalar instructions in the pixel shader.   Yes, that's exactly what it does. (And the horizon map contains the sine of the angle to the horizon, which is the highest feature in the bump map in a local neighborhood around each texel.)
  7.   There is actually a way to do horizon mapping well, and I describe it in Chapter 5 of Game Engine Gems 3: https://www.amazon.com/dp/1498755658/?tag=terathon-20
  8. Here's one solution, but I'm not sure if it's what you're looking for:   http://transvoxel.org/
  9. Eric Lengyel

    Foundations of Game Engine Development

    These 200 pages correspond to the same range of topics that were covered in about 70 pages of my old math book. The new book goes into a lot more detail and covers new topics like Grassmann algebra that are not discussed in my old book at all. Topics related to graphics, animation, and physics that constitute the bulk of my old math book are going to be covered separately in future volumes of the Foundations of Game Engine Development series.
  10. The first volume in my new book series, Foundations of Game Engine Development, has been released on Amazon.com!   [attachment=33228:vol1.jpg]   This book covers the mathematics needed by game developers. The full table of contents and more information about the series can be found here:   http://foundationsofgameenginedev.com/  
  11. Eric Lengyel

    Math Book For Game Programming

      I'm not seeing that on Amazon. Where can one obtain a copy?     It's not out yet. I'll put a link to the Amazon page on the above website when it's available. And I'll tweet it. (@EricLengyel)
  12. Eric Lengyel

    Math Book For Game Programming

    Thanks for the plug, Ravyne. I also have a new book coming out this month that covers more topics and goes into a lot more detail:   http://foundationsofgameenginedev.com/
  13. Eric Lengyel

    Stencil Shadows Problem

      This part doesn't sound right. One side should increase, and the other side should decrease. Your shadow is where the stencil ends up being nonzero.
  14. Eric Lengyel

    Plane equation, + or - D

    A plane (a,b,c,d) is really a four-dimensional trivector, not an ordinary vector. When you take the wedge product of three points P, Q, and R, it naturally produces a plane in which d = -dot(N, P) = -dot(N, Q) = -dot(N, R), where N = (a,b,c). When you take the dot product between a homogeneous point (x,y,z,w) and a plane (a,b,c,d), you get a*x + b*y + c*z + d*w, which gives you the signed distance between the point and the plane multiplied by w and the magnitude of N. A positive sign in front of the d is the correct choice.   This kind of stuff is discussed very thoroughly in my new book that comes out in August:   http://foundationsofgameenginedev.com/   Dirk, when a homogeneous point is treated as a single-column matrix that is transformed by multiplying on the left by a 4x4 matrix M, a 4D plane must be treated as a single-row matrix that is transformed by multiplying on the right by the adjugate of the matrix M. If the translation portion of the matrix M is not zero, then a plane will not be transformed correctly if you treat it the same as a point.
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