-
Notifications
You must be signed in to change notification settings - Fork 15
/
Copy pathmain.cpp
175 lines (141 loc) · 5.1 KB
/
main.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
//Game.hpp declares the "game" object, which handles game-specific stuff:
#include "Game.hpp"
//GL.hpp will include a non-namespace-polluting set of opengl prototypes:
#include "GL.hpp"
//Includes for libSDL:
#include <SDL.h>
//...and for glm:
#include <glm/glm.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/matrix_transform.hpp>
//...and for c++ standard library functions:
#include <chrono>
#include <iostream>
#include <stdexcept>
#include <fstream>
#include <memory>
#include <algorithm>
int main(int argc, char **argv) {
struct {
//TODO: this is where you set the title and size of your game window
std::string title = "TODO: Game Title";
glm::uvec2 size = glm::uvec2(640, 400);
} config;
//------------ initialization ------------
//Initialize SDL library:
SDL_Init(SDL_INIT_VIDEO);
//Ask for an OpenGL context version 3.3, core profile, enable debug:
SDL_GL_ResetAttributes();
SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
//create window:
SDL_Window *window = SDL_CreateWindow(
config.title.c_str(),
SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
config.size.x, config.size.y,
SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI
);
//prevent exceedingly tiny windows when resizing:
SDL_SetWindowMinimumSize(window, 100, 100);
if (!window) {
std::cerr << "Error creating SDL window: " << SDL_GetError() << std::endl;
return 1;
}
//Create OpenGL context:
SDL_GLContext context = SDL_GL_CreateContext(window);
if (!context) {
SDL_DestroyWindow(window);
std::cerr << "Error creating OpenGL context: " << SDL_GetError() << std::endl;
return 1;
}
#ifdef _WIN32
//On windows, load OpenGL extensions:
init_gl_shims();
#endif
//Set VSYNC + Late Swap (prevents crazy FPS):
if (SDL_GL_SetSwapInterval(-1) != 0) {
std::cerr << "NOTE: couldn't set vsync + late swap tearing (" << SDL_GetError() << ")." << std::endl;
if (SDL_GL_SetSwapInterval(1) != 0) {
std::cerr << "NOTE: couldn't set vsync (" << SDL_GetError() << ")." << std::endl;
}
}
//Hide mouse cursor (note: showing can be useful for debugging):
//SDL_ShowCursor(SDL_DISABLE);
//------------ create game object (loads assets) --------------
std::shared_ptr< Game > game = std::make_shared< Game >();
//------------ main loop ------------
//the window created above is resizable; this inline function will be
//called whenever the window is resized, and will update the window_size
//and drawable_size variables:
glm::uvec2 window_size; //size of window (layout pixels)
glm::uvec2 drawable_size; //size of drawable (physical pixels)
//On non-highDPI displays, window_size will always equal drawable_size.
auto on_resize = [&](){
int w,h;
SDL_GetWindowSize(window, &w, &h);
window_size = glm::uvec2(w, h);
SDL_GL_GetDrawableSize(window, &w, &h);
drawable_size = glm::uvec2(w, h);
glViewport(0, 0, drawable_size.x, drawable_size.y);
};
on_resize();
//This will loop until the game object is set to null:
while (game) {
//every pass through the game loop creates one frame of output
// by performing three steps:
{ //(1) process any events that are pending
static SDL_Event evt;
while (SDL_PollEvent(&evt) == 1) {
//handle resizing:
if (evt.type == SDL_WINDOWEVENT && evt.window.event == SDL_WINDOWEVENT_SIZE_CHANGED) {
on_resize();
}
//handle input:
if (game && game->handle_event(evt, window_size)) {
// mode handled it; great
} else if (evt.type == SDL_QUIT) {
game.reset(); //done: deallocate game
break;
}
}
if (!game) break;
}
{ //(2) call the game's "update" function to deal with elapsed time:
auto current_time = std::chrono::high_resolution_clock::now();
static auto previous_time = current_time;
float elapsed = std::chrono::duration< float >(current_time - previous_time).count();
previous_time = current_time;
//if frames are taking a very long time to process,
//lag to avoid spiral of death:
elapsed = std::min(0.1f, elapsed);
game->update(elapsed);
if (!game) break;
}
{ //(3) call the game's "draw" function to produce output:
//clear the depth+color buffers and set some default state:
glClearColor(0.5, 0.5, 0.5, 0.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
game->draw(drawable_size);
}
//Finally, wait until the recently-drawn frame is shown before doing it all again:
SDL_GL_SwapWindow(window);
}
//------------ teardown ------------
SDL_GL_DeleteContext(context);
context = 0;
SDL_DestroyWindow(window);
window = NULL;
return 0;
}