Simple Noise Example

Introduction

This code is constructed to demonstrate a short and easy to understand example. The example is of how noise can be used and generated in basic C++ code.

Using the Code

The code is written in C++ and was last run in "Dev-C++". Please contact me with problems on using the code in other IDEs.

#include <iostream>
#include <time.h>
#include <cstdlib>
#include <windows.h>
#include <stdio.h>     
#include <math.h> 
using namespace std;

//The height and width of the total area
int gridWidth=1000;
int gridHeight=1000;

//Function for setting start position of "rand()" function values.
void setStartNumber2d(int x,int y){
    //The X and Y values are set to valid values by using the "absolute value" to avoid negativ inputs.
    //       The Absolute Value
    //       |------------|
    x=((int)  sqrt(pow(x,2)))  %gridWidth;
    y=((int)  sqrt(pow(y,2)))  %gridHeight;
    //The rand value is reset to make sure that the start value is always the same.
    srand(1);
    //The current rand value is found with using a for loop.
    for(int i=0;i!=x+y*gridWidth;i++)rand();
    //There is no return value as the function only sets the "start position" for the rand value.
}
int main(){
    // X & Y position is stored in integers.
    int x=0;
    int y=0;

    // The screen size is adapted to fit a console window.
    int screenWidth=80;
    int screenHeight=38;

    // The "randomValues" array is used to store random integers. 
    // It is ten units wider than the screen; It is also ten units higher.
    int randomValues[(screenWidth+10)*(screenHeight+10)];
    int whereInArray=0;
    int total;

    char totalLow=' ';
    char totalMedium=176;
    char totalHigh=177;
    char totalHigher=178;

    // String out is used to output the noise result in characters.
    string out="";

    while(true){
        system("pause");

        // GetAsyncKeyState is used to apply movement.
        if(GetAsyncKeyState(VK_LEFT))x--;
        if(GetAsyncKeyState(VK_RIGHT))x++;
        if(GetAsyncKeyState(VK_UP))y--;
        if(GetAsyncKeyState(VK_DOWN))y++;

        // Here "setStartNumber2d" is used to set our current position.
        setStartNumber2d(x,y);

        // This for loop is used to reset each integer in the "randomValues" array to zero.
        for(int i=0;i<(screenWidth+10)*(screenHeight+10);i++)randomValues[i]=0;

        // The first for loop is used to loop through all y-values of the "randomValues" 
        // the next will loop through all the x-values.
        for(int y=0;y<(screenHeight+10);y++){
            for(int x=0;x<(screenWidth+10);x++){
                //To determine where in the array the value should be applied the 
                //X value is added to the Y value times the max-X value.
                whereInArray=x+y*(screenWidth+10);
                //For each X and Y position the value applied to "randomValues" 
                //will either be zero or one.
                if(rand()%1000>500){
                    randomValues[whereInArray]=1;
                }else{
                    randomValues[whereInArray]=0;
                }
            }

            //This for loops finishes one full line of the grid to later continue 
            //on the next Y value of the grid.
            for(int x=0;x<gridWidth-(screenWidth+10);x++){rand();
            }
        }

        //The "out" string is reset.
        out="";

        // The first for loop is used to loop through all y-values of the screen 
        // the next will loop through all the x-values.
        for(int y=0;y<screenHeight;y++){   
            for(int x=0;x<screenWidth;x++){
                total=0;
                //These loops will run through a circular area to find the total 
                //of the randomValues in this area.
                //The area looks something like this:
                //  ---   xxx
                //   |   xxxxx
                // 10|   xxxxx
                //   |   xxxxx
                //  ---   xxx
                for(int circularSearchY=-5;circularSearchY<5;circularSearchY++){
                    //Cosine is the X distance from X=0
                    int cosine=sqrt(pow(5,2)-pow(circularSearchY,2));
                    //This for loop will through all X values for the current Y position.
                    for(int circularSearchX=0-cosine;circularSearchX<cosine;circularSearchX++){
                        //Depending on the stored value zero or one is added 
                        //from the "randomValues" array.
                        total+=randomValues[(x+5+circularSearchX)+(y+5+circularSearchY)*90];
                    }
                }
                //After the total is summed different characters are accordingly 
                //added to the "out" string.
                if(total<33)out+=totalLow;
                if(total>32&&total<36)out+=totalMedium;
                if(total>35&&total<40)out+=totalHigh;
                if(total>39)out+=totalHigher;
            }
        }
        //The previous screen is cleared.
        system("cls");
        //The out string isprinted to the screen.
        cout<<out;
    }
}

Points of Interest

Please contact me with questions, suggestions or potential problems on ruben.skrappost@gmail.com.