Normal quotes

66-01.md

@@ -3,47 +3,47 @@
   ------------------------ --------------------------------- --------------------
 
 Chapter 66\
- Quake’s Hidden-Surface Removal {#Heading1}
+ Quake's Hidden-Surface Removal {#Heading1}
 -------------------------------
 
 ### Struggling with Z-Order Solutions to the Hidden Surface Problem {#Heading2}
 
-Okay, I admit it: I’m sick and tired of classic rock. Admittedly, it’s
+Okay, I admit it: I'm sick and tired of classic rock. Admittedly, it's
 been a while, about 20 years, since I was last excited to hear anything
 by the Cars or Boston, and I was never particularly excited in the first
 place about Bob Seger or Queen, to say nothing of Elvis, so some things
-haven’t changed. But I knew something was up when I found myself
+haven't changed. But I knew something was up when I found myself
 changing the station on the Allman Brothers and Steely Dan and Pink
-Floyd and, God help me, the Beatles (just stuff like “Hello Goodbye” and
-“I’ll Cry Instead,” though, not “Ticket to Ride” or “A Day in the Life”;
-I’m not *that* far gone). It didn’t take long to figure out what the
-problem was; I’d been hearing the same songs for a quarter-century, and
+Floyd and, God help me, the Beatles (just stuff like "Hello Goodbye" and
+"I'll Cry Instead," though, not "Ticket to Ride" or "A Day in the Life";
+I'm not *that* far gone). It didn't take long to figure out what the
+problem was; I'd been hearing the same songs for a quarter-century, and
 I was bored.
 
 I tell you this by way of explaining why it was that when my daughter
 and I drove back from dinner the other night, the radio in my car was
-tuned, for the first time ever, to a station whose slogan is “There is
-no alternative.”
+tuned, for the first time ever, to a station whose slogan is "There is
+no alternative."
 
-Now, we’re talking here about a 10-year-old who worships the Beatles and
+Now, we're talking here about a 10-year-old who worships the Beatles and
 has been raised on a steady diet of oldies. She loves melodies, catchy
-songs, and good singers, none of which you’re likely to find on an
-alternative rock station. So it’s no surprise that when I turned on the
-radio, the first word out of her mouth was “Yuck!”
+songs, and good singers, none of which you're likely to find on an
+alternative rock station. So it's no surprise that when I turned on the
+radio, the first word out of her mouth was "Yuck!"
 
 What did surprise me was that after listening for a while, she said,
-“You know, Dad, it’s actually kind of interesting.”
+"You know, Dad, it's actually kind of interesting."
 
 Apart from giving me a clue as to what sort of music I can expect to
-hear blasting through our house when she’s a teenager, her quick uptake
+hear blasting through our house when she's a teenager, her quick uptake
 on alternative rock (versus my decades-long devotion to the music of my
-youth) reminded me of something that it’s easy to forget as we become
-older and more set in our ways. It reminded me that it’s essential to
+youth) reminded me of something that it's easy to forget as we become
+older and more set in our ways. It reminded me that it's essential to
 keep an open mind, and to be willing, better yet, eager, to try new
 things. Programmers tend to become attached to familiar approaches, and
 are inclined to stick with whatever is currently doing the job
 adequately well, but in programming there are always alternatives, and
-I’ve found that they’re often worth considering.
+I've found that they're often worth considering.
 
 Not that I should have needed any reminding, considering the
 ever-evolving nature of Quake.
@@ -51,8 +51,8 @@ ever-evolving nature of Quake.
 ### Creative Flux and Hidden Surfaces {#Heading3}
 
 Back in Chapter 64, I described the creative flux that led to John
-Carmack’s decision to use a precalculated potentially visible set (PVS)
-of polygons for each possible viewpoint in Quake, the game we’re
+Carmack's decision to use a precalculated potentially visible set (PVS)
+of polygons for each possible viewpoint in Quake, the game we're
 developing here at id Software. The precalculated PVS meant that instead
 of having to spend a lot of time searching through the world database to
 find out which polygons were visible from the current viewpoint, we
@@ -60,23 +60,23 @@ could simply draw all the polygons in the PVS from back-to-front
 (getting the ordering courtesy of the world BSP tree) and get the
 correct scene drawn with no searching at all; letting the back-to-front
 drawing perform the final stage of hidden-surface removal (HSR). This
-was a terrific idea, but it was far from the end of the road for Quake’s
+was a terrific idea, but it was far from the end of the road for Quake's
 design.
 
 #### Drawing Moving Objects {#Heading4}
 
 For one thing, there was still the question of how to sort and draw
 moving objects properly; in fact, this is the single technical question
-I’ve been asked most often in recent months, so I’ll take a moment to
+I've been asked most often in recent months, so I'll take a moment to
 address it here. The primary problem is that a moving model can span
 multiple BSP leaves, with the leaves that are touched varying as the
 model moves; that, together with the possibility of multiple models in
-one leaf, means there’s no easy way to use BSP order to draw the models
+one leaf, means there's no easy way to use BSP order to draw the models
 in correctly sorted order. When I wrote Chapter 64, we were drawing
 sprites (such as explosions), moveable BSP models (such as doors), and
 polygon models (such as monsters) by clipping each into all the leaves
 it touched, then drawing the appropriate parts as each BSP leaf was
-reached in back-to-front traversal. However, this didn’t solve the issue
+reached in back-to-front traversal. However, this didn't solve the issue
 of sorting multiple moving models in a single leaf against each other,
 and also left some ugly sorting problems with complex polygon models.
 
@@ -86,7 +86,7 @@ each pixel, we compare its distance, or z, value with the z value of the
 pixel currently on the screen, drawing only if the new pixel is nearer
 than the current one.) First, we draw the basic world, walls, ceilings,
 and the like. No z-buffer *testing* is involved at this point (the world
-visible surface determination is done in a different way, as we’ll see
+visible surface determination is done in a different way, as we'll see
 soon); however, we do *fill* the z-buffer with the z values (actually,
 1/z values, as discussed below) for all the world pixels. Z-filling is a
 much faster process than z-buffering the entire world would be, because
@@ -97,8 +97,8 @@ around.
 
 #### Performance Impact {#Heading5}
 
-Whenever a z-buffer is involved, the questions inevitably are: What’s
-the memory footprint and what’s the performance impact? Well, the memory
+Whenever a z-buffer is involved, the questions inevitably are: What's
+the memory footprint and what's the performance impact? Well, the memory
 footprint at 320x200 is 128K, not trivial but not a big deal for a game
 that requires 8 MB to run. The performance impact is about 10 percent
 for z-filling the world, and roughly 20 percent (with lots of variation)
@@ -114,9 +114,9 @@ performance cost.
 
 As I said above, in the Quake architecture, the world itself is drawn
 first, without z-buffer reads or compares, but filling the z-buffer with
-the world polygons’ z values, and then the moving objects are drawn atop
-the world, using full z-buffering. Thus far, I’ve discussed how to draw
-moving objects. For the rest of this chapter, I’m going to talk about
+the world polygons' z values, and then the moving objects are drawn atop
+the world, using full z-buffering. Thus far, I've discussed how to draw
+moving objects. For the rest of this chapter, I'm going to talk about
 the other part of the drawing equation; that is, how to draw the world
 itself, where the entire world is stored as a single BSP tree and never
 moves.