applied further typos and fixes

This commit is contained in:
Lokathor 2018-11-11 00:40:49 -07:00
parent db00e1e24d
commit 6ceba1d9dc
5 changed files with 33 additions and 14 deletions

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@ -12,22 +12,27 @@ GBA game, so it's a good starting one to go over for that reason too.
The display control register holds a `u16` value, and is located at `0x0400_0000`.
Many of the bits here won't mean much to you right now. **That is fine.** You do
NOT need to memorize them all or what they all do right away. We'll just skim
over all the parts of this register to start, and then we'll go into more detail
in later chapters when we need to come back and use more of the bits.
## Video Modes
The lowest three bits (0-2) let you select from among the GBA's six video modes.
You'll notice that 3 bits allows for eight modes, but the values 6 and 7 are
prohibited.
Modes 0, 1, and 2 are "Tiled" modes. These are actually the modes that you
Modes 0, 1, and 2 are "tiled" modes. These are actually the modes that you
should eventually learn to use as much as possible. It lets the GBA's limited
video hardware do as much of the work as possible, leaving more of your CPU time
for gameplay computations. However, they're also complex enough to deserve their
own demos and chapters later on, so that's all we'll say about them for now.
Modes 3, 4, and 5 are "Bitmap" modes. These let you write individual pixels to
Modes 3, 4, and 5 are "bitmap" modes. These let you write individual pixels to
locations on the screen.
* **Mode 3** is full resolution (240w x 160h) RBG15 color. You might not be used
* **Mode 3** is full resolution (240w x 160h) RGB15 color. You might not be used
to RGB15, since modern computers have 24 or 32 bit colors. In RGB15, there's 5
bits for each color channel stored within a `u16` value, and the highest bit is
simply ignored.
@ -64,7 +69,9 @@ Bit 5 lets you access OAM during HBlank if enabled. This is cool, but it reduces
the maximum sprites per scanline, so it's not default.
Bit 6 lets you adjust if the GBA should treat Object Character VRAM as being 2d
(off) or 1d (on).
(off) or 1d (on). This particular control can be kinda tricky to wrap your head
around, so we'll be sure to have some extra diagrams in the chapter that deals
with it.
Bit 7 forces the screen to stay in vblank as long as it's set. This allows the
fastest use of the VRAM, Palette, and Object Attribute Memory. Obviously if you

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@ -145,19 +145,23 @@ that we can get a hint of what's to come.</p>
<p>Also it's the one that you basically always need to set at least once in every
GBA game, so it's a good starting one to go over for that reason too.</p>
<p>The display control register holds a <code>u16</code> value, and is located at <code>0x0400_0000</code>.</p>
<p>Many of the bits here won't mean much to you right now. <strong>That is fine.</strong> You do
NOT need to memorize them all or what they all do right away. We'll just skim
over all the parts of this register to start, and then we'll go into more detail
in later chapters when we need to come back and use more of the bits.</p>
<a class="header" href="#video-modes" id="video-modes"><h2>Video Modes</h2></a>
<p>The lowest three bits (0-2) let you select from among the GBA's six video modes.
You'll notice that 3 bits allows for eight modes, but the values 6 and 7 are
prohibited.</p>
<p>Modes 0, 1, and 2 are &quot;Tiled&quot; modes. These are actually the modes that you
<p>Modes 0, 1, and 2 are &quot;tiled&quot; modes. These are actually the modes that you
should eventually learn to use as much as possible. It lets the GBA's limited
video hardware do as much of the work as possible, leaving more of your CPU time
for gameplay computations. However, they're also complex enough to deserve their
own demos and chapters later on, so that's all we'll say about them for now.</p>
<p>Modes 3, 4, and 5 are &quot;Bitmap&quot; modes. These let you write individual pixels to
<p>Modes 3, 4, and 5 are &quot;bitmap&quot; modes. These let you write individual pixels to
locations on the screen.</p>
<ul>
<li><strong>Mode 3</strong> is full resolution (240w x 160h) RBG15 color. You might not be used
<li><strong>Mode 3</strong> is full resolution (240w x 160h) RGB15 color. You might not be used
to RGB15, since modern computers have 24 or 32 bit colors. In RGB15, there's 5
bits for each color channel stored within a <code>u16</code> value, and the highest bit is
simply ignored.</li>
@ -186,7 +190,9 @@ the 0th page is used, and when the bit is 1 the 1st page is used.</p>
<p>Bit 5 lets you access OAM during HBlank if enabled. This is cool, but it reduces
the maximum sprites per scanline, so it's not default.</p>
<p>Bit 6 lets you adjust if the GBA should treat Object Character VRAM as being 2d
(off) or 1d (on).</p>
(off) or 1d (on). This particular control can be kinda tricky to wrap your head
around, so we'll be sure to have some extra diagrams in the chapter that deals
with it.</p>
<p>Bit 7 forces the screen to stay in vblank as long as it's set. This allows the
fastest use of the VRAM, Palette, and Object Attribute Memory. Obviously if you
leave this on for too long the player will notice a blank screen, but it might

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@ -499,19 +499,23 @@ that we can get a hint of what's to come.</p>
<p>Also it's the one that you basically always need to set at least once in every
GBA game, so it's a good starting one to go over for that reason too.</p>
<p>The display control register holds a <code>u16</code> value, and is located at <code>0x0400_0000</code>.</p>
<p>Many of the bits here won't mean much to you right now. <strong>That is fine.</strong> You do
NOT need to memorize them all or what they all do right away. We'll just skim
over all the parts of this register to start, and then we'll go into more detail
in later chapters when we need to come back and use more of the bits.</p>
<a class="header" href="#video-modes" id="video-modes"><h2>Video Modes</h2></a>
<p>The lowest three bits (0-2) let you select from among the GBA's six video modes.
You'll notice that 3 bits allows for eight modes, but the values 6 and 7 are
prohibited.</p>
<p>Modes 0, 1, and 2 are &quot;Tiled&quot; modes. These are actually the modes that you
<p>Modes 0, 1, and 2 are &quot;tiled&quot; modes. These are actually the modes that you
should eventually learn to use as much as possible. It lets the GBA's limited
video hardware do as much of the work as possible, leaving more of your CPU time
for gameplay computations. However, they're also complex enough to deserve their
own demos and chapters later on, so that's all we'll say about them for now.</p>
<p>Modes 3, 4, and 5 are &quot;Bitmap&quot; modes. These let you write individual pixels to
<p>Modes 3, 4, and 5 are &quot;bitmap&quot; modes. These let you write individual pixels to
locations on the screen.</p>
<ul>
<li><strong>Mode 3</strong> is full resolution (240w x 160h) RBG15 color. You might not be used
<li><strong>Mode 3</strong> is full resolution (240w x 160h) RGB15 color. You might not be used
to RGB15, since modern computers have 24 or 32 bit colors. In RGB15, there's 5
bits for each color channel stored within a <code>u16</code> value, and the highest bit is
simply ignored.</li>
@ -540,7 +544,9 @@ the 0th page is used, and when the bit is 1 the 1st page is used.</p>
<p>Bit 5 lets you access OAM during HBlank if enabled. This is cool, but it reduces
the maximum sprites per scanline, so it's not default.</p>
<p>Bit 6 lets you adjust if the GBA should treat Object Character VRAM as being 2d
(off) or 1d (on).</p>
(off) or 1d (on). This particular control can be kinda tricky to wrap your head
around, so we'll be sure to have some extra diagrams in the chapter that deals
with it.</p>
<p>Bit 7 forces the screen to stay in vblank as long as it's set. This allows the
fastest use of the VRAM, Palette, and Object Attribute Memory. Obviously if you
leave this on for too long the player will notice a blank screen, but it might

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