Difference between revisions of "Gb.pickRandomSeed"
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(Added example) |
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The function is defined in the library as follows: | The function is defined in the library as follows: | ||
| − | < | + | <pre> |
void Gamebuino::pickRandomSeed(){ | void Gamebuino::pickRandomSeed(){ | ||
| − | + | randomSeed(battery.voltage * ~micros() + backlight.ambientLight + micros()); | |
} | } | ||
| − | </ | + | </pre> |
The range of values of each part of the function are: | The range of values of each part of the function are: | ||
| Line 19: | Line 19: | ||
This allows seed values ranging from 0 to 4294964116 (for an unsigned long). | This allows seed values ranging from 0 to 4294964116 (for an unsigned long). | ||
| − | Realistically, values are expected to be in the range of | + | Realistically, values are expected to be in the range of 23,761 to 4,293,588,651. (Achieved using a fully charged Gamebuino) |
== Syntax == | == Syntax == | ||
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<pre> | <pre> | ||
/* | /* | ||
| − | * | + | * pickRandomSeed function example - By Jack Burgess (aka Matrix828) |
* | * | ||
| − | * A demo that performs the gb. | + | * A demo that performs the gb.pickRandomSeed() function and displays the result, |
* with the highest and lowest generated values shown as well. | * with the highest and lowest generated values shown as well. | ||
* | * | ||
| Line 50: | Line 50: | ||
void setup() { | void setup() { | ||
gb.begin(); | gb.begin(); | ||
| − | gb.titleScreen(F(" | + | gb.titleScreen(F("pickRandomSeed Example")); |
} | } | ||
Revision as of 2014-08-04T22:44:24
Description
Picks a random seed using a mix of the battery voltage, ambient light sensor and the time elapsed since start up. It should be placed right after gb.begin() and gb.titleScreen(), this way the random seed will depend on how long the user takes to press "A" to leave the title screen.
The function is defined in the library as follows:
void Gamebuino::pickRandomSeed(){
randomSeed(battery.voltage * ~micros() + backlight.ambientLight + micros());
}
The range of values of each part of the function are:
-
battery.voltage: 4200 to 3500 -
~micros(): -1 to -4,294,967,293 -
backlight.ambientLight: 0 to 1024 -
micros(): 0 to 4,294,967,292
This allows seed values ranging from 0 to 4294964116 (for an unsigned long). Realistically, values are expected to be in the range of 23,761 to 4,293,588,651. (Achieved using a fully charged Gamebuino)
Syntax
gb.pickRandomSeed();
Parameters
none
Returns
none
Example
/*
* pickRandomSeed function example - By Jack Burgess (aka Matrix828)
*
* A demo that performs the gb.pickRandomSeed() function and displays the result,
* with the highest and lowest generated values shown as well.
*
*/
#include <SPI.h>
#include <Gamebuino.h>
Gamebuino gb;
unsigned long seed;
unsigned long highest = 0;
unsigned long lowest = 429130353; // Random high value
void setup() {
gb.begin();
gb.titleScreen(F("pickRandomSeed Example"));
}
void loop(){
while (1){
if(gb.update()){
seed = gb.battery.voltage * ~micros() + gb.backlight.ambientLight + micros();
if (seed > highest) {
highest = seed;
} else if (seed < lowest) {
lowest = seed;
}
gb.display.print(F("Highest:"));
gb.display.println(highest);
gb.display.print(F("Lowest: "));
gb.display.println(lowest);
gb.display.print(F("Seed: "));
gb.display.println(seed);
}
}
}
