Intermediate C++ Game Programming Tutorial 23 - Revision history

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2020-05-04T21:19:57Z

‎Video Timestamp Index

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2020-05-04T21:18:10Z

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2020-05-04T21:15:34Z

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2020-05-04T21:11:48Z

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2019-11-26T22:17:29Z

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2019-11-26T22:17:04Z

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2019-11-26T22:16:16Z

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2019-11-26T22:15:29Z

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2019-11-26T22:14:44Z

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2019-11-26T22:13:02Z

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@@ Line 59: / Line 59: @@
 <div class="mw-collapsible-content">
 :* Bitwise NOT (<code>~a</code>): unary operation that flips all the bits of <code>a</code>
-*:- Use case: switch off an option: <code>options &= ~option1;</code>
+::- Use case: switch off an option: <code>options &= ~option1;</code>
 :* Bitwise XOR (<code>^</code>): binary operation sets each bit position to 1 only if the bits at that position of the two operands are different
-*:- Use case: a "configurable flipper". <code>a^0b11110000</code> will flip the 4 left bits of <code>a</code> and leave the 4 right bits the same
+::- Use case: a "configurable flipper". <code>a^0b11110000</code> will flip the 4 left bits of <code>a</code> and leave the 4 right bits the same
-*:- Toggle an option: <code>options ^= option1;</code>
+::- Toggle an option: <code>options ^= option1;</code>
 </div>
 * Don't use Bitwise AND in logical operations like <code>if ( a & b )</code> [https://youtu.be/WPMwq0qM8Kk?t=19m49s 19:49]
@@ Line 69: / Line 69: @@
 :* <code>bool( 0b01 && 0b10 )</code> is true, whereas <code>bool( 0b01 & 0b10 )</code> is false
 :* Only reason why you would want to use <code>&</code> in logical operations is to avoid short circuiting evaluations with <code>&&</code> or <code>||</code>
-*:- Short circuiting stops evaluating a comparison when the first argument is evaluated
+::- Short circuiting stops evaluating a comparison when the first argument is evaluated
-*:- For instance: <code>if ( false && ... )</code> will not evaluate anything after <code>&&</code> because it is irrelevant
+::- For instance: <code>if ( false && ... )</code> will not evaluate anything after <code>&&</code> because it is irrelevant
-*:- To be safe when you do this, use <code>if ( bool(a) & bool(b) )</code>
+::- To be safe when you do this, use <code>if ( bool(a) & bool(b) )</code>
 </div>
 * Bitwise arithmetic optimizations [https://youtu.be/WPMwq0qM8Kk?t=22m30s 22:30]

@@ Line 30: / Line 30: @@
 * Bitwise operators AND (<code>&</code>), OR (<code>|</code>) [https://youtu.be/WPMwq0qM8Kk?t=1m50s 1:50]
 <div class="mw-collapsible-content">
-** Biswise AND (<code>&</code>): 1010 & 1100 = 1000, also called a mask
+:* Biswise AND (<code>&</code>): 1010 & 1100 = 1000, also called a mask
-** Biswise OR (<code>|</code>): 1010 | 1100 = 1110, also called a mash
+:* Biswise OR (<code>|</code>): 1010 | 1100 = 1110, also called a mash
 </div>
 * Shifting operations left (<code><<</code>), right (<code>>></code>) [https://youtu.be/WPMwq0qM8Kk?t=5m10s 5:10]
 <div class="mw-collapsible-content">
-** Shift left (<code><<</code>): 0011 << 1 = 0110, shifts binary zeros in from the right side into the lower order bit position
+:* Shift left (<code><<</code>): 0011 << 1 = 0110, shifts binary zeros in from the right side into the lower order bit position
-** Shift right (<code>>></code>): 0110 >> 2 = 0001, shifts binary zeros in from the left side into the highter order bit position
+:* Shift right (<code>>></code>): 0110 >> 2 = 0001, shifts binary zeros in from the left side into the highter order bit position
-** Except for negative integers: <code>(-1)>>n</code>: ...1111>>2 = ...1111, shifts binary ones in from the left
+:* Except for negative integers: <code>(-1)>>n</code>: ...1111>>2 = ...1111, shifts binary ones in from the left
 </div>
 * Packing and unpacking data, masking with <code>&</code> and mashing/combining with <code>|</code> [https://youtu.be/WPMwq0qM8Kk?t=7m07s 7:07]
 <div class="mw-collapsible-content">
-** Example: combining four 8-bit numbers into one 32-bit number by using <code><<</code> and <code>|</code>
+:* Example: combining four 8-bit numbers into one 32-bit number by using <code><<</code> and <code>|</code>
-** Example: unpacking a 32-bit number to an 8 bit sequence by using <code>&</code> and <code>>></code>
+:* Example: unpacking a 32-bit number to an 8 bit sequence by using <code>&</code> and <code>>></code>
 </div>
 * Example use case: The <code>Color</code> class in the Framework [https://youtu.be/WPMwq0qM8Kk?t=12m20s 12:20]
 <div class="mw-collapsible-content">
-** XRGB 8-bit values are packed into a 32-bit word using <code>(x<<24u) | (r<<16u) | (g<<8u) | b)</code>
+:* XRGB 8-bit values are packed into a 32-bit word using <code>(x<<24u) | (r<<16u) | (g<<8u) | b)</code>
 </div>
 * Packing flag values into a single integer parameter [https://youtu.be/WPMwq0qM8Kk?t=14m29s 14:29]
 <div class="mw-collapsible-content">
-** Used in libraries such as the Windows API, DirectX, in STL
+:* Used in libraries such as the Windows API, DirectX, in STL
-** Each value is represented by a single bit set in their binary representation
+:* Each value is represented by a single bit set in their binary representation
-** For example: <code>enum Options { option1 = 0b01, option2 = 0b10 };</code>
+:* For example: <code>enum Options { option1 = 0b01, option2 = 0b10 };</code>
-** Check for options with Bitwise AND: if you have an <code>int options</code>, check the option flag using <code>if( options & option1 )</code>
+:* Check for options with Bitwise AND: if you have an <code>int options</code>, check the option flag using <code>if( options & option1 )</code>
-** Combine options with Bitwise OR: make an <code>int options = option1 | option3;</code>
+:* Combine options with Bitwise OR: make an <code>int options = option1 | option3;</code>
 </div>
 * Advanced Bitwise operators NOT (<code>~</code>), XOR (<code>^</code>) [https://youtu.be/WPMwq0qM8Kk?t=16m48s 16:48]
 <div class="mw-collapsible-content">
-** Bitwise NOT (<code>~a</code>): unary operation that flips all the bits of <code>a</code>
+:* Bitwise NOT (<code>~a</code>): unary operation that flips all the bits of <code>a</code>
 *:- Use case: switch off an option: <code>options &= ~option1;</code>
-** Bitwise XOR (<code>^</code>): binary operation sets each bit position to 1 only if the bits at that position of the two operands are different
+:* Bitwise XOR (<code>^</code>): binary operation sets each bit position to 1 only if the bits at that position of the two operands are different
 *:- Use case: a "configurable flipper". <code>a^0b11110000</code> will flip the 4 left bits of <code>a</code> and leave the 4 right bits the same
 *:- Toggle an option: <code>options ^= option1;</code>
@@ Line 66: / Line 66: @@
 * Don't use Bitwise AND in logical operations like <code>if ( a & b )</code> [https://youtu.be/WPMwq0qM8Kk?t=19m49s 19:49]
 <div class="mw-collapsible-content">
-** <code>bool(x)</code> evaluates to false if x==0, otherwise to true
+:* <code>bool(x)</code> evaluates to false if x==0, otherwise to true
-** <code>bool( 0b01 && 0b10 )</code> is true, whereas <code>bool( 0b01 & 0b10 )</code> is false
+:* <code>bool( 0b01 && 0b10 )</code> is true, whereas <code>bool( 0b01 & 0b10 )</code> is false
-** Only reason why you would want to use <code>&</code> in logical operations is to avoid short circuiting evaluations with <code>&&</code> or <code>||</code>
+:* Only reason why you would want to use <code>&</code> in logical operations is to avoid short circuiting evaluations with <code>&&</code> or <code>||</code>
 *:- Short circuiting stops evaluating a comparison when the first argument is evaluated
 *:- For instance: <code>if ( false && ... )</code> will not evaluate anything after <code>&&</code> because it is irrelevant
@@ Line 75: / Line 75: @@
 * Bitwise arithmetic optimizations [https://youtu.be/WPMwq0qM8Kk?t=22m30s 22:30]
 <div class="mw-collapsible-content">
-** <code>x >> n</code> divides x by 2^n (as in: 2 to the power of n)
+:* <code>x >> n</code> divides x by 2^n (as in: 2 to the power of n)
-** <code>x << n</code> multiplies x by 2^n (as in: 2 to the power of n)
+:* <code>x << n</code> multiplies x by 2^n (as in: 2 to the power of n)
-** <code>x % 16</code> is equal to <code>x & 15</code> or <code>x & 0xF</code>
+:* <code>x % 16</code> is equal to <code>x & 15</code> or <code>x & 0xF</code>
-** Note: no need to apply this in your code, the compiler will do this anyway when it optimizes
+:* Note: no need to apply this in your code, the compiler will do this anyway when it optimizes
 </div>
 </div>

@@ Line 14: / Line 14: @@
 * Converting integers to their binary representations [https://youtu.be/WPMwq0qM8Kk?t=0m25s 0:25]
 <div class="mw-collapsible-content">
-** Introducing <code>std::string ToBin(unsigned int n, int min_digits=0);</code>
+:* Introducing <code>std::string ToBin(unsigned int n, int min_digits=0);</code>
 ::<syntaxhighlight lang="cpp" line>
-struct EqVec2
+std::string ToBin( unsigned int n, int min_digits = 0)
+{
-    template <typename T>
+	std::string bin_str;
-    bool operator()( const T& lhs,const T& rhs ) const
+	for ( int count = 0; n!=0 || count < min_digits; n>>=1,count++ )
-−
+	{
-        return (lhs.x == rhs.x) && (lhs.y == rhs.y);
+		bin_str.push_back( bool( n & 0b1 ) ? '1' : '0' );
-−
+	}
-};
+	std::reverse( bin_str.begin(),bin_str.end() );
 </syntaxhighlight>
 </div>

@@ Line 14: / Line 14: @@
 * Converting integers to their binary representations [https://youtu.be/WPMwq0qM8Kk?t=0m25s 0:25]
 <div class="mw-collapsible-content">
 ** Introducing <code>std::string ToBin(unsigned int n, int min_digits=0);</code>
 </div>
 * Bitwise operators AND (<code>&</code>), OR (<code>|</code>) [https://youtu.be/WPMwq0qM8Kk?t=1m50s 1:50]

@@ Line 12: / Line 12: @@
 [https://youtu.be/WPMwq0qM8Kk Tutorial 23]
 <div class="mw-collapsible mw-collapsed"><br />
-* Converting integers to their binary representation [https://youtu.be/WPMwq0qM8Kk?t=0m25s 0:25]
+* Converting integers to their binary representations [https://youtu.be/WPMwq0qM8Kk?t=0m25s 0:25]
 <div class="mw-collapsible-content">
 ** Introducing <code>std::string ToBin(unsigned int n, int min_digits=0);</code>