Normal quotes

68-01.md

@@ -3,7 +3,7 @@
   ------------------------ --------------------------------- --------------------
 
 Chapter 68\
- Quake’s Lighting Model {#Heading1}
+ Quake's Lighting Model {#Heading1}
 -----------------------
 
 ### A Radically Different Approach to Lighting Polygons {#Heading2}
@@ -25,50 +25,50 @@ detract from the sheer thrill of being in a computer-simulated universe.
 Then the college got a PDP-11 with four CRT terminals, and suddenly Star
 Trek could redraw in a second instead of a minute. Better yet, I found
 the source code for the Star Trek program in the recesses of the new
-system, the first time I’d ever seen any real-world code other than my
+system, the first time I'd ever seen any real-world code other than my
 own, and excitedly dove into it. One evening, as I was looking through
 the code, a really cute girl at the next terminal asked me for help
 getting a program to run. After I had helped her, eager to get to know
-her better, I said, “Want to see something? This is the actual source
-for the Star Trek game!” and proceeded to page through the code,
+her better, I said, "Want to see something? This is the actual source
+for the Star Trek game!" and proceeded to page through the code,
 describing each subroutine. We got to talking, and eventually I worked
 up the nerve to ask her out. She said sure, and we ended up having a
 good time, although things soon fell apart because of her two or three
 other boyfriends (I never did get an exact count). The interesting
 thing, though, was her response when I finally got around to asking her
-out. She said, “It’s about time!” When I asked what she meant, she said,
-“I’ve been trying to get you to ask me out all evening—but it took you
-forever! You didn’t actually think I was interested in that Star Trek
-program, did you?”
+out. She said, "It's about time!" When I asked what she meant, she said,
+"I've been trying to get you to ask me out all evening—but it took you
+forever! You didn't actually think I was interested in that Star Trek
+program, did you?"
 
 Actually, yes, I had thought that, because *I* was interested in it. One
 thing I learned from that experience, and have had reinforced countless
 times since, is that we—you, me, anyone who programs because they love
-it, who would do it for free if necessary—are a breed apart. We’re
+it, who would do it for free if necessary—are a breed apart. We're
 different, and luckily so; while everyone else is worrying about
-downsizing, we’re in one of the hottest industries in the world. And, so
-far as I can see, the biggest reason we’re in such a good situation
-isn’t intelligence, or hard work, or education, although those help;
-it’s that we actually *like* this stuff.
+downsizing, we're in one of the hottest industries in the world. And, so
+far as I can see, the biggest reason we're in such a good situation
+isn't intelligence, or hard work, or education, although those help;
+it's that we actually *like* this stuff.
 
-It’s important to keep it that way. I’ve seen far too many people start
+It's important to keep it that way. I've seen far too many people start
 to treat programming like a job, forgetting the joy of doing it, and
-burn out. So keep an eye on how you feel about the programming you’re
-doing, and if it’s getting stale, it’s time to learn something new;
-there’s plenty of interesting programming of all sorts to be done.
-Follow your interests—and don’t forget to have fun!
+burn out. So keep an eye on how you feel about the programming you're
+doing, and if it's getting stale, it's time to learn something new;
+there's plenty of interesting programming of all sorts to be done.
+Follow your interests—and don't forget to have fun!
 
 ### The Lighting Conundrum {#Heading3}
 
-I spent about two years working with John Carmack on Quake’s 3-D
+I spent about two years working with John Carmack on Quake's 3-D
 graphics engine. John faced several fundamental design issues while
-architecting Quake. I’ve written in earlier chapters about some of those
+architecting Quake. I've written in earlier chapters about some of those
 issues, including eliminating non-visible polygons quickly via a
 precalculated potentially visible set (PVS), and improving performance
 by inserting potentially visible polygons into a global edge list and
 scanning out only the nearest polygon at each pixel.
 
-In this chapter, I’m going to talk about another, equally crucial design
+In this chapter, I'm going to talk about another, equally crucial design
 issue: how we developed our lighting approach for the part of the Quake
 engine that draws the world itself, the static walls and floors and
 ceilings. Monsters and players are drawn using completely different
@@ -77,7 +77,7 @@ world, on the other hand, was to be as precise as possible, getting
 everything right so that polygons, textures, and sophisticated lighting
 would be pegged in place, with no visible shifting or distortion under
 all viewing conditions, for maximum player immersion—all with good
-performance, of course. As I’ll discuss, the twin goals of performance
+performance, of course. As I'll discuss, the twin goals of performance
 and rock-solid, complex lighting proved to be difficult to achieve with
 traditional lighting approaches; ultimately, a dramatically different
 approach was required.
@@ -91,10 +91,10 @@ all relevant world lighting, linearly interpolating between lighting
 values down the edges of the polygon, and then linearly interpolating
 between the edges of the polygon across each span. If texture mapping is
 desired (and all polygons are texture mapped in Quake), then at each
-pixel in each span, the pixel’s corresponding texture map location
+pixel in each span, the pixel's corresponding texture map location
 (texel) is determined, and the interpolated lighting is applied to the
 texel to generate a final, lit pixel. Texels are generally taken from a
-32x32 or 64x64 texture that’s tiled repeatedly across the polygon, for
+32x32 or 64x64 texture that's tiled repeatedly across the polygon, for
 several reasons: performance (a 64x64 texture sits nicely in the 486 or
 Pentium cache), database size, and less artwork.
 
@@ -107,7 +107,7 @@ is lit by looking up the pixel color in a table, using the texel color
 and the lighting intensity as the look-up indices.
 
 Gouraud shading allows for decent lighting effects with a relatively
-small amount of calculation and a compact data set that’s a simple
+small amount of calculation and a compact data set that's a simple
 extension of the basic polygon model. However, there are several
 important drawbacks to Gouraud shading, as well.