engine.game source code

1 /*
2     Copyright © 2020, Luna Nielsen
3     Distributed under the 2-Clause BSD License, see LICENSE file.
4     
5     Authors: Luna Nielsen
6 */
7 module engine.game;
8 import bindbc.glfw;
9 import engine;
10 
11 private double previousTime_;
12 private double currentTime_;
13 private double deltaTime_;
14 
15 /**
16     Function run when the game is to initialize
17 */
18 void function() gameInit;
19 
20 /**
21     Function run when the game is to update
22 */
23 void function() gameUpdate;
24 
25 /**
26     Function run after the main rendering has happened, Used to draw borders for the gameplay
27 */
28 void function() gameBorder;
29 
30 /**
31     Function run after updates and rendering of the game
32 */
33 void function() gamePostUpdate;
34 
35 /**
36     Function run when the game is to clean up
37 */
38 void function() gameCleanup;
39 
40 /**
41     Starts the game loop
42 
43     viewportSize sets the desired viewport size for the framebuffer, defaults to 1080p (1920x1080)
44 */
45 void startGame(vec2i viewportSize = vec2i(1920, 1080)) {
46     gameInit();
47     resetTime();
48 
49     Framebuffer framebuffer = new Framebuffer(GameWindow, viewportSize);
50     while(!GameWindow.isExitRequested) {
51 
52         currentTime_ = glfwGetTime();
53         deltaTime_ = currentTime_-previousTime_;
54         previousTime_ = currentTime_;
55         
56         // Bind our framebuffer
57         framebuffer.bind();
58 
59             // Clear color and depth buffers
60             glClearColor(0, 0, 0, 1);
61             glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
62 
63             // Update and render the game
64             gameUpdate();
65 
66         // Unbind our framebuffer
67         framebuffer.unbind();
68     
69         // Clear color and depth bits
70         glClearColor(0, 0, 0, 0);
71         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
72 
73         // Draw border, framebuffer and post update content
74         if (gameBorder !is null) gameBorder();
75         framebuffer.renderToFit();
76         if (gamePostUpdate !is null) gamePostUpdate();
77 
78         // Update the mouse's state
79         Mouse.update();
80         Input.update();
81 
82         // Swap buffers and update the window
83         GameWindow.swapBuffers();
84         GameWindow.update();
85     }
86 
87     // Pop all states
88     GameStateManager.popAll();
89 
90     // Game cleanup
91     gameCleanup();
92 }
93 
94 /**
95     Gets delta time
96 */
97 double deltaTime() {
98     return deltaTime_;
99 }
100 
101 /**
102     Gets delta time
103 */
104 double prevTime() {
105     return previousTime_;
106 }
107 
108 /**
109     Gets delta time
110 */
111 double currTime() {
112     return currentTime_;
113 }
114 
115 /**
116     Resets the time scale
117 */
118 void resetTime() {
119     glfwSetTime(0);
120     previousTime_ = 0;
121     currentTime_ = 0;
122 }