1 00:00:01,003 --> 00:00:02,008 - [Instructor] Hi, this video is 2 00:00:02,008 --> 00:00:05,002 Building the levelManager Class. 3 00:00:05,002 --> 00:00:07,008 In the previous video, we learned about designing levels. 4 00:00:07,008 --> 00:00:12,006 In this video, we're going to code LevelManager.h 5 00:00:12,006 --> 00:00:15,007 and LevelManager.cpp. 6 00:00:15,007 --> 00:00:17,003 It will take several phases of coding 7 00:00:17,003 --> 00:00:19,008 to make our level designs work. 8 00:00:19,008 --> 00:00:21,003 The first thing we will do 9 00:00:21,003 --> 00:00:23,008 is code the LevelManager header file. 10 00:00:23,008 --> 00:00:25,006 This will allow us to look at and discuss 11 00:00:25,006 --> 00:00:27,004 the member variables and functions 12 00:00:27,004 --> 00:00:30,000 that will be in the LevelManager Class. 13 00:00:30,000 --> 00:00:34,001 Next, we will code the LevelManager.cpp file 14 00:00:34,001 --> 00:00:37,004 which will have all the function definitions in it. 15 00:00:37,004 --> 00:00:39,009 As this is a long file, we will break it up 16 00:00:39,009 --> 00:00:43,003 into several sections to code and discuss them. 17 00:00:43,003 --> 00:00:45,009 Once the LevelManager Class is complete, 18 00:00:45,009 --> 00:00:47,008 we will add an instance of it 19 00:00:47,008 --> 00:00:50,001 to the game engine, Engine Class. 20 00:00:50,001 --> 00:00:52,000 We will also add a new function 21 00:00:52,000 --> 00:00:54,002 to the Engine Class loadLevel which we can call 22 00:00:54,002 --> 00:00:58,004 from the update function whenever a new level is required. 23 00:00:58,004 --> 00:01:00,007 The loadLevel function will not only 24 00:01:00,007 --> 00:01:03,009 use the LevelManager instance to load the appropriate level, 25 00:01:03,009 --> 00:01:06,003 but it will also take care of aspects 26 00:01:06,003 --> 00:01:08,001 such as spawning the player characters 27 00:01:08,001 --> 00:01:10,004 and preparing the clock. 28 00:01:10,004 --> 00:01:12,008 As already mentioned, let's get an overview 29 00:01:12,008 --> 00:01:16,004 of LevelManager by coding the LevelManager.h file. 30 00:01:16,004 --> 00:01:20,002 Create a .h file is always right click header files 31 00:01:20,002 --> 00:01:24,004 in the solution explorer and select add new item. 32 00:01:24,004 --> 00:01:27,007 Click headerfile.h, and then, in the name field, 33 00:01:27,007 --> 00:01:29,009 type LevelManager. 34 00:01:29,009 --> 00:01:32,003 Lastly, click Add. 35 00:01:32,003 --> 00:01:34,000 We are now ready to code the header file 36 00:01:34,000 --> 00:01:36,004 for the LevelManager Class. 37 00:01:36,004 --> 00:01:39,004 Now add this highlighted code to the file. 38 00:01:39,004 --> 00:01:42,000 It consists of necessary include directives 39 00:01:42,000 --> 00:01:44,000 and private variables. 40 00:01:44,000 --> 00:01:46,003 Here we're adding an include directive 41 00:01:46,003 --> 00:01:49,006 called SFML Graphics.hpp. 42 00:01:49,006 --> 00:01:54,002 Then, we are using namespace sf and namespace std. 43 00:01:54,002 --> 00:01:56,005 In the LevelManager Class, 44 00:01:56,005 --> 00:01:59,005 these are the various private variables. 45 00:01:59,005 --> 00:02:04,002 The code first declares Vector2im_LevelSize 46 00:02:04,002 --> 00:02:07,000 to hold two integer values that will hold the horizontal 47 00:02:07,000 --> 00:02:11,000 and vertical number of tiles that the current map contains. 48 00:02:11,000 --> 00:02:15,007 Vector2fm_StartPosition contains the coordinates 49 00:02:15,007 --> 00:02:19,005 in the world where Bob and Thomas should be spawned. 50 00:02:19,005 --> 00:02:22,004 Note that this is not a tile position relatable 51 00:02:22,004 --> 00:02:25,000 to m_LevelSize units, 52 00:02:25,000 --> 00:02:29,002 but a horizontal and vertical pixel position in the level. 53 00:02:29,002 --> 00:02:33,006 The m_TimeModifier member variable is a float 54 00:02:33,006 --> 00:02:36,001 that will be used to multiply the time available 55 00:02:36,001 --> 00:02:37,006 in the current level. 56 00:02:37,006 --> 00:02:39,009 The reason we want to do this is so that by changing, 57 00:02:39,009 --> 00:02:41,007 decreasing this value 58 00:02:41,007 --> 00:02:43,008 we will shorten the time available each time 59 00:02:43,008 --> 00:02:46,001 the player attempts the same level. 60 00:02:46,001 --> 00:02:48,007 As an example, if the player gets 60 seconds 61 00:02:48,007 --> 00:02:51,001 for the first time they attempt level one 62 00:02:51,001 --> 00:02:55,002 then, 60 multiplied by one is of course 60. 63 00:02:55,002 --> 00:02:57,004 When the player completes all the levels 64 00:02:57,004 --> 00:03:00,001 and comes back to level one for the second time, 65 00:03:00,001 --> 00:03:04,004 m_TimeModifier will have been reduced by 10%. 66 00:03:04,004 --> 00:03:08,003 Then, when the time available is multiplied by 0.9, 67 00:03:08,003 --> 00:03:10,006 the amount of time available to the player 68 00:03:10,006 --> 00:03:12,003 will be 54 seconds. 69 00:03:12,003 --> 00:03:14,007 This is 10% less than 60. 70 00:03:14,007 --> 00:03:17,000 The game will get steadily harder. 71 00:03:17,000 --> 00:03:21,005 The float variable m_Base time limit holds the original 72 00:03:21,005 --> 00:03:24,006 unmodified time limit we have just been discussing. 73 00:03:24,006 --> 00:03:28,000 You can probably guess that m_CurrentLevel 74 00:03:28,000 --> 00:03:31,006 will hold the current level number that is being played. 75 00:03:31,006 --> 00:03:36,002 The int NUM_Levels constant will be used to flag 76 00:03:36,002 --> 00:03:39,003 when it is appropriate to go back to level one again 77 00:03:39,003 --> 00:03:44,002 and reduce the value of m_TimeModifier. 78 00:03:44,002 --> 00:03:45,009 Next, add this highlighted code 79 00:03:45,009 --> 00:03:50,000 which consists public variables and function declarations. 80 00:03:50,000 --> 00:03:51,006 Let's go through it. 81 00:03:51,006 --> 00:03:54,009 Notice that there are two constant int members. 82 00:03:54,009 --> 00:03:58,008 TILE_size is a useful constant to remind us 83 00:03:58,008 --> 00:04:00,009 that each tile in the sprite sheet 84 00:04:00,009 --> 00:04:04,007 is 50 pixels wide and 50 pixels high. 85 00:04:04,007 --> 00:04:08,009 VERTS_IN_QUAD is a useful constant 86 00:04:08,009 --> 00:04:11,007 to make our manipulation of a vertex array 87 00:04:11,007 --> 00:04:13,005 less error prone. 88 00:04:13,005 --> 00:04:16,005 There are, in fact, four vertices in a quad. 89 00:04:16,005 --> 00:04:18,007 Now we can't forget it. 90 00:04:18,007 --> 00:04:22,005 The get TimeLimit, get StartPosition, get LevelSize, 91 00:04:22,005 --> 00:04:25,007 and get CurrentLevel functions are simple getter functions 92 00:04:25,007 --> 00:04:28,004 that return the current value 93 00:04:28,004 --> 00:04:31,007 of the private member variables 94 00:04:31,007 --> 00:04:35,001 we declared in the previous block of code. 95 00:04:35,001 --> 00:04:38,009 A function that deserves a closer look is nextLevel. 96 00:04:38,009 --> 00:04:40,004 This function receives a vertex array reference 97 00:04:40,004 --> 00:04:42,000 just like we use in the Zombie Arena game. 98 00:04:42,000 --> 00:04:44,005 The function can then work on the vertex array 99 00:04:44,005 --> 00:04:46,000 and all the changes will be present 100 00:04:46,000 --> 00:04:48,006 in the vertex array from the calling code. 101 00:04:48,006 --> 00:04:51,007 The next level function returns a pointer to a pointer 102 00:04:51,007 --> 00:04:53,002 which means we can return an address 103 00:04:53,002 --> 00:04:54,003 that is the first segment 104 00:04:54,003 --> 00:04:57,006 of a two dimensional array of int values. 105 00:04:57,006 --> 00:05:00,001 We will be building a two dimensional array 106 00:05:00,001 --> 00:05:04,001 of int values that will represent the layout of each level. 107 00:05:04,001 --> 00:05:06,006 Of course, these int values will be read 108 00:05:06,006 --> 00:05:09,004 from the level designed text files. 109 00:05:09,004 --> 00:05:13,004 Now we'll code the LevelManager.cpp file. 110 00:05:13,004 --> 00:05:16,005 Right click Source Files in the solution explorer, 111 00:05:16,005 --> 00:05:17,009 and select add new item. 112 00:05:17,009 --> 00:05:22,003 In the add new item window, select C++ file, 113 00:05:22,003 --> 00:05:24,008 and then rename the file to LevelManager. 114 00:05:24,008 --> 00:05:26,005 Lastly, click Add. 115 00:05:26,005 --> 00:05:29,001 We are now ready to code the .cpp file 116 00:05:29,001 --> 00:05:31,006 for the LevelManager Class. 117 00:05:31,006 --> 00:05:33,009 As this is quite a long class, we'll break it up 118 00:05:33,009 --> 00:05:36,003 to discuss it in six chunks. 119 00:05:36,003 --> 00:05:38,008 The first five will cover the nextLevel function, 120 00:05:38,008 --> 00:05:41,001 and the sixth all the rest. 121 00:05:41,001 --> 00:05:43,002 Add this highlighted code. 122 00:05:43,002 --> 00:05:45,009 Here we are adding Shows Include Directives, 123 00:05:45,009 --> 00:05:50,002 and the first of five part of the nextLevel function. 124 00:05:50,002 --> 00:05:52,002 After the include directives, 125 00:05:52,002 --> 00:05:56,007 the code initializes m_LevelSize.x and 126 00:05:56,007 --> 00:05:59,009 m_LevelSIze.y to zero. 127 00:05:59,009 --> 00:06:03,005 Next, m_CurrentLevel is incremented. 128 00:06:03,005 --> 00:06:05,003 The if statement that follows checks 129 00:06:05,003 --> 00:06:10,007 whether m_CurrentLevel is greater than NUM_Levels. 130 00:06:10,007 --> 00:06:14,003 If it is, m_CurrentLevel is sent back to zero, 131 00:06:14,003 --> 00:06:19,002 and m_TimeModifier is reduced by 0.1f 132 00:06:19,002 --> 00:06:22,002 in order to shorten the time allowed for all levels. 133 00:06:22,002 --> 00:06:25,000 The code then switches based on the value held by 134 00:06:25,000 --> 00:06:27,003 m_CurrentLevel. 135 00:06:27,003 --> 00:06:30,002 Each case statement initializes the name of the text file 136 00:06:30,002 --> 00:06:32,001 which holds the level design. 137 00:06:32,001 --> 00:06:34,004 And the starting position for Thomas and Bob, 138 00:06:34,004 --> 00:06:35,002 as well as m_BaseTimeLimit 139 00:06:35,002 --> 00:06:38,007 which is the unmodified time limit 140 00:06:38,007 --> 00:06:40,008 for the level in question. 141 00:06:40,008 --> 00:06:44,000 Now add the second part of the nextLevel function. 142 00:06:44,000 --> 00:06:45,004 Add this highlighted code 143 00:06:45,004 --> 00:06:47,004 immediately after the previous code. 144 00:06:47,004 --> 00:06:49,004 We'll go through it in detail. 145 00:06:49,004 --> 00:06:53,007 First, we declare an if stream object called input file 146 00:06:53,007 --> 00:06:55,006 which opens a stream to the file name 147 00:06:55,006 --> 00:06:57,007 contained in leveltoLoad. 148 00:06:57,007 --> 00:07:00,001 The code loops through each line of the file 149 00:07:00,001 --> 00:07:03,006 using get line, but doesn't record any of its content. 150 00:07:03,006 --> 00:07:06,009 All it does is count the number of lines by incrementing 151 00:07:06,009 --> 00:07:09,006 m_LevelSize.y. 152 00:07:09,006 --> 00:07:12,000 After the while loop, the width of the level 153 00:07:12,000 --> 00:07:17,003 is saved in m_LevelSize.x using s.length. 154 00:07:17,003 --> 00:07:20,007 This implies that the level length of all the lines 155 00:07:20,007 --> 00:07:23,000 must be the same or we would run into trouble. 156 00:07:23,000 --> 00:07:24,007 At this point, we know and have saved 157 00:07:24,007 --> 00:07:26,009 the length and width of the current level 158 00:07:26,009 --> 00:07:29,008 in m_LevelSize. 159 00:07:29,008 --> 00:07:32,008 Now add the third part of the next level function. 160 00:07:32,008 --> 00:07:36,003 Add this code immediately after the previous code. 161 00:07:36,003 --> 00:07:39,003 Here, we first, we clear Input file 162 00:07:39,003 --> 00:07:41,003 using its clear function. 163 00:07:41,003 --> 00:07:45,009 The seek g function called with the zero ios beg parameters 164 00:07:45,009 --> 00:07:49,008 resets the string back to before the first character. 165 00:07:49,008 --> 00:07:53,008 Next, we declare a pointer to a pointer called arrayLevel. 166 00:07:53,008 --> 00:07:56,008 Note that this is done on the free store or heap 167 00:07:56,008 --> 00:07:58,008 using the new key word. 168 00:07:58,008 --> 00:08:00,009 Once we have initialized this two dimensional array, 169 00:08:00,009 --> 00:08:03,007 we'll be able to return its address to the calling code, 170 00:08:03,007 --> 00:08:06,000 and it will persist until we either delete it 171 00:08:06,000 --> 00:08:08,002 or the game is closed. 172 00:08:08,002 --> 00:08:14,004 This is for loop loops from zero to m-LevelSize.y minus one. 173 00:08:14,004 --> 00:08:17,009 In each pass, it adds a new array of int values 174 00:08:17,009 --> 00:08:23,005 to the heap to match the value of m_LevelSize.x. 175 00:08:23,005 --> 00:08:27,001 We now have a perfectly configured for the current level 176 00:08:27,001 --> 00:08:27,009 two dimensional array. 177 00:08:27,009 --> 00:08:30,008 The only problem is that there's nothing in it. 178 00:08:30,008 --> 00:08:34,003 Next, we add the fourth part of the nextLevel function. 179 00:08:34,003 --> 00:08:37,005 Add this code immediately after the previous code. 180 00:08:37,005 --> 00:08:41,002 First, the code initializes a string called row 181 00:08:41,002 --> 00:08:44,006 which will hold one row of the level design at the time. 182 00:08:44,006 --> 00:08:48,000 We also declare and initialize and int called y 183 00:08:48,000 --> 00:08:50,003 that will help us count the rows. 184 00:08:50,003 --> 00:08:53,007 The while loop executes repeatedly until input file 185 00:08:53,007 --> 00:08:55,006 gets past the last row. 186 00:08:55,006 --> 00:08:58,006 Inside the while loop, there is a for loop 187 00:08:58,006 --> 00:09:01,000 which goes through each character of the current row 188 00:09:01,000 --> 00:09:04,004 and stores it in the two dimensional array, arrayLevel. 189 00:09:04,004 --> 00:09:07,001 Notice that we assess exactly the right element 190 00:09:07,001 --> 00:09:09,005 of the two dimensional array 191 00:09:09,005 --> 00:09:11,009 with arrayLevel, array of y, and x. 192 00:09:11,009 --> 00:09:16,000 The a to i function converts char val to int. 193 00:09:16,000 --> 00:09:18,002 This is what is required because we have 194 00:09:18,002 --> 00:09:21,003 a two dimensional array for int not char. 195 00:09:21,003 --> 00:09:26,000 Over here, we increment y and lastly close the file. 196 00:09:26,000 --> 00:09:29,004 Now add the fifth part of the nextLevel function. 197 00:09:29,004 --> 00:09:32,002 Add the code right after the previous one. 198 00:09:32,002 --> 00:09:34,004 This is entire highlighted code. 199 00:09:34,004 --> 00:09:37,000 Just after close the file. 200 00:09:37,000 --> 00:09:39,003 Although this is the longest section of code 201 00:09:39,003 --> 00:09:42,000 from the five sections we divided nextLevel into, 202 00:09:42,000 --> 00:09:44,000 it is also the most straight forward. 203 00:09:44,000 --> 00:09:47,002 What happens is that the nested for loop loops 204 00:09:47,002 --> 00:09:50,002 from zero through to the width and height of the level. 205 00:09:50,002 --> 00:09:52,009 For each position in the array, four vertices are 206 00:09:52,009 --> 00:09:56,001 put into vertex array and for text coordinates 207 00:09:56,001 --> 00:09:58,001 are assigned from the sprite sheet. 208 00:09:58,001 --> 00:10:00,006 The positions of the vertices and texture coordinates 209 00:10:00,006 --> 00:10:03,005 are calculated using the current vertex available 210 00:10:03,005 --> 00:10:09,000 the tile size and VERTS_IN_QUAD constants. 211 00:10:09,000 --> 00:10:11,009 At the end of each loop of the inner for loop, 212 00:10:11,009 --> 00:10:16,002 current vertex is increased by VERTS_IN_QUAD 213 00:10:16,002 --> 00:10:19,000 moving nicely onto the next tile. 214 00:10:19,000 --> 00:10:21,007 The important thing to remember about this vertex array 215 00:10:21,007 --> 00:10:23,007 is that it was passed into nextLevel by reference 216 00:10:23,007 --> 00:10:26,006 therefore the vertex array will be available 217 00:10:26,006 --> 00:10:28,000 in the calling code. 218 00:10:28,000 --> 00:10:31,003 We will call nextLevel from the code in the Engine Class. 219 00:10:31,003 --> 00:10:32,009 Once this function has been called, 220 00:10:32,009 --> 00:10:34,007 the Engine Class will have a vertex array 221 00:10:34,007 --> 00:10:36,007 to represent the level graphically. 222 00:10:36,007 --> 00:10:39,004 A two dimensional array of int values 223 00:10:39,004 --> 00:10:41,009 as a numerical representation of all the platforms 224 00:10:41,009 --> 00:10:44,002 and obstacles in the level. 225 00:10:44,002 --> 00:10:46,000 The last part is remaining now. 226 00:10:46,000 --> 00:10:48,002 You have to add this highlighted code after the end 227 00:10:48,002 --> 00:10:50,004 of nextLevel function. 228 00:10:50,004 --> 00:10:52,007 Here we are adding rest of the functions 229 00:10:52,007 --> 00:10:54,006 from LevelManager Class. 230 00:10:54,006 --> 00:10:58,004 These LevelManager functions are all simple getter functions 231 00:10:58,004 --> 00:11:00,008 but do take the time to familiarize yourself 232 00:11:00,008 --> 00:11:04,003 with what private value is returned by which function. 233 00:11:04,003 --> 00:11:06,009 Now that the LevelManager Class is complete 234 00:11:06,009 --> 00:11:09,001 we can move on to using it. 235 00:11:09,001 --> 00:11:12,006 We will code another function in the Engine Class to do so. 236 00:11:12,006 --> 00:11:14,000 Cool! 237 00:11:14,000 --> 00:11:15,004 In this video, we have learned 238 00:11:15,004 --> 00:11:17,005 building the LevelManager Class. 239 00:11:17,005 --> 00:11:21,001 Next up, we'll code the loadLevel function.