AK47 Spray Pattern

clear all
clc
close all

%% 0. Parameters of spray pattern
% There are 2 parameters: spray and spread
% 0a. Spray is about the 'central' points. This determines where each
% magazine's bullet goes. For example, if we have a list with 30
% numbers, the 17-th number of the list determines the position
% of 17-th bullet in the magazine
% 0b. Spread is the variation of this 'expected' position.
% The bullet may not go to this exact expected spot, but in
% a sligthly altered direction. Ofc, there is a higher
% possibility the bullet will land close to the 'central'
% points. More spread means higher possibility for the bullet
% to be off-target.



%% 1. Spray
I = imread('AK47.png');
% figure();
% imshow(I);
figure();
AK47 = [206 780; 211 764; 207 701; 212 589; 221 477; 180 366; 151 268; 98 192; 160 135; 315 157; 339 97; 386 134; 401 89; 486 119; 495 98; 363 89; 293 58; 235 34; 144 36; 106 37; 80 60; 22 74; 92 75; 60 37; 51 27; 113 17; 131 28; 236 30; 388 94; 443 92];
N = size(AK47, 1);
AK47x = AK47(:, 1);
AK47y = -AK47(:, 2);
plot(AK47x, AK47y, 'ro', 'MarkerSize', 8.5);
hold on
plot(AK47x, AK47y, 'red');
title('AK47 Spray Pattern');
reds = ones(N, 1);
greens = linspace(225, 0, N)' / 255;
blues = zeros(N, 1);
colors = [reds greens blues];

% Mode 1
mode1 = 1;
spread1 = 0;
bullets1 = spray_and_spread(AK47, N, spread1, mode1);

% Mode 2
spread2 = 2.5;
mode2 = 2;
bullets2 = spray_and_spread(AK47, N, spread2, mode2);

% Mode 3
spread3 = 2.5;
mode3 = 3;
bullets3 = spray_and_spread(AK47, N, spread3, mode3);

% Plots
plot_patterns(bullets1, bullets2, colors, N);
title('CSGO vs Standard Spread');
plot_patterns(bullets1, bullets3, colors, N);
title('CSGO vs CS2');


%% 2. Spread
% There will be 3 modes:
% 2a. No spread like CSGO
% 2b. Standard spread in each bullet
% 2c. Increasing spread like CS2 meaning that shooting consecutive
% bullets will increase the spread factor in them, so the last ones
% will experience a higher spread that the first ones

function bullets = spray_and_spread(AK47, N, spread, mode)

    if(mode == 1)
        % No spread
        offset_x = zeros(N, 1);
        offset_y = zeros(N, 1);
    elseif(mode == 2)
        % Standard spread
        R = spread * rand(N, 1);
        angles = 2*pi * rand(N, 1);
        offset_x = R .* cos(angles);
        offset_y = R .* sin(angles);
    elseif(mode == 3)
        % Increasing spread
        spreads = spread * (1:N)';
        R = spreads .* rand(N, 1);
        angles = 2*pi * rand(N, 1);
        offset_x = R .* cos(angles);
        offset_y = R .* sin(angles);
    else
        % Random spread
        offset_x = randn(N, 1);
        offset_y = randn(N, 1);
    end

    bullets_temp = AK47 + [offset_x offset_y];
    bullets = [bullets_temp(:, 1) -bullets_temp(:, 2)];

end



%% Mode vs mode plot
function plot_patterns(bullets1, bullets2, colors, N)

    x1 = bullets1(:, 1);        y1 = bullets1(:, 2);
    x2 = bullets2(:, 1);        y2 = bullets2(:, 2);
    figure();
    for i = 1 : N
        plot(x1(i), y1(i), 'Marker', 'o', 'Color', colors(i, :), 'MarkerSize', 8.5);
        hold on
        plot(x2(i), y2(i), 'Marker', 'x', 'Color', colors(i, :), 'MarkerSize', 8.5);
        hold on
    end
    plot(x1, y1, 'black');

end