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1 
2 /* Simple program:  Create a blank window, wait for keypress, quit.
3 
4    Please see the SDL documentation for details on using the SDL API:
5    /Developer/Documentation/SDL/docs.html
6 */
7 
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <string.h>
11 #include <math.h>
12 
13 #include "SDL.h"
14 
15 extern void Atlantis_Init ();
16 extern void Atlantis_Reshape (int w, int h);
17 extern void Atlantis_Animate ();
18 extern void Atlantis_Display ();
19 
20 static SDL_Surface *gScreen;
21 
initAttributes()22 static void initAttributes ()
23 {
24     // Setup attributes we want for the OpenGL context
25 
26     int value;
27 
28     // Don't set color bit sizes (SDL_GL_RED_SIZE, etc)
29     //    Mac OS X will always use 8-8-8-8 ARGB for 32-bit screens and
30     //    5-5-5 RGB for 16-bit screens
31 
32     // Request a 16-bit depth buffer (without this, there is no depth buffer)
33     value = 16;
34     SDL_GL_SetAttribute (SDL_GL_DEPTH_SIZE, value);
35 
36 
37     // Request double-buffered OpenGL
38     //     The fact that windows are double-buffered on Mac OS X has no effect
39     //     on OpenGL double buffering.
40     value = 1;
41     SDL_GL_SetAttribute (SDL_GL_DOUBLEBUFFER, value);
42 }
43 
printAttributes()44 static void printAttributes ()
45 {
46     // Print out attributes of the context we created
47     int nAttr;
48     int i;
49 
50     int  attr[] = { SDL_GL_RED_SIZE, SDL_GL_BLUE_SIZE, SDL_GL_GREEN_SIZE,
51                     SDL_GL_ALPHA_SIZE, SDL_GL_BUFFER_SIZE, SDL_GL_DEPTH_SIZE };
52 
53     char *desc[] = { "Red size: %d bits\n", "Blue size: %d bits\n", "Green size: %d bits\n",
54                      "Alpha size: %d bits\n", "Color buffer size: %d bits\n",
55                      "Depth bufer size: %d bits\n" };
56 
57     nAttr = sizeof(attr) / sizeof(int);
58 
59     for (i = 0; i < nAttr; i++) {
60 
61         int value;
62         SDL_GL_GetAttribute (attr[i], &value);
63         printf (desc[i], value);
64     }
65 }
66 
createSurface(int fullscreen)67 static void createSurface (int fullscreen)
68 {
69     Uint32 flags = 0;
70 
71     flags = SDL_OPENGL;
72     if (fullscreen)
73         flags |= SDL_FULLSCREEN;
74 
75     // Create window
76     gScreen = SDL_SetVideoMode (640, 480, 0, flags);
77     if (gScreen == NULL) {
78 
79         fprintf (stderr, "Couldn't set 640x480 OpenGL video mode: %s\n",
80                  SDL_GetError());
81 		SDL_Quit();
82 		exit(2);
83 	}
84 }
85 
initGL()86 static void initGL ()
87 {
88     Atlantis_Init ();
89     Atlantis_Reshape (gScreen->w, gScreen->h);
90 }
91 
drawGL()92 static void drawGL ()
93 {
94     Atlantis_Animate ();
95     Atlantis_Display ();
96 }
97 
mainLoop()98 static void mainLoop ()
99 {
100     SDL_Event event;
101     int done = 0;
102     int fps = 24;
103 	int delay = 1000/fps;
104     int thenTicks = -1;
105     int nowTicks;
106 
107     while ( !done ) {
108 
109 		/* Check for events */
110 		while ( SDL_PollEvent (&event) ) {
111 			switch (event.type) {
112 
113 				case SDL_MOUSEMOTION:
114 					break;
115 				case SDL_MOUSEBUTTONDOWN:
116 					break;
117 				case SDL_KEYDOWN:
118 					/* Any keypress quits the app... */
119 				case SDL_QUIT:
120 					done = 1;
121 					break;
122 				default:
123 					break;
124 			}
125 		}
126 
127         // Draw at 24 hz
128         //     This approach is not normally recommended - it is better to
129         //     use time-based animation and run as fast as possible
130         drawGL ();
131         SDL_GL_SwapBuffers ();
132 
133         // Time how long each draw-swap-delay cycle takes
134         // and adjust delay to get closer to target framerate
135         if (thenTicks > 0) {
136             nowTicks = SDL_GetTicks ();
137             delay += (1000/fps - (nowTicks-thenTicks));
138             thenTicks = nowTicks;
139             if (delay < 0)
140                 delay = 1000/fps;
141         }
142         else {
143             thenTicks = SDL_GetTicks ();
144         }
145 
146         SDL_Delay (delay);
147 	}
148 }
149 
main(int argc,char * argv[])150 int main(int argc, char *argv[])
151 {
152 	// Init SDL video subsystem
153 	if ( SDL_Init (SDL_INIT_VIDEO) < 0 ) {
154 
155         fprintf(stderr, "Couldn't initialize SDL: %s\n",
156 			SDL_GetError());
157 		exit(1);
158 	}
159 
160     // Set GL context attributes
161     initAttributes ();
162 
163     // Create GL context
164     createSurface (0);
165 
166     // Get GL context attributes
167     printAttributes ();
168 
169     // Init GL state
170     initGL ();
171 
172     // Draw, get events...
173     mainLoop ();
174 
175     // Cleanup
176 	SDL_Quit();
177 
178     return 0;
179 }
180