e14743d1 |
1 | /* |
2 | * Small SDL example to demonstrate dynamically loading |
3 | * OpenGL lib and functions |
4 | * |
5 | * (FYI it was supposed to look like snow in the wind or something...) |
6 | * |
7 | * Compile with : |
8 | * gcc testdyngl.c `sdl-config --libs --cflags` -o testdyngl -DHAVE_OPENGL |
9 | * |
10 | * You can specify a different OpenGL lib on the command line, i.e. : |
11 | * ./testdyngl /usr/X11R6/lib/libGL.so.1.2 |
12 | * or |
13 | * ./testdyngl /usr/lib/libGL.so.1.0.4496 |
14 | * |
15 | */ |
16 | |
17 | #include <stdio.h> |
18 | #include <stdlib.h> |
19 | |
20 | #include "SDL.h" |
21 | |
22 | #ifdef __MACOS__ |
23 | #define HAVE_OPENGL |
24 | #endif |
25 | |
26 | #ifdef HAVE_OPENGL |
27 | |
28 | #include "SDL_opengl.h" |
29 | |
30 | /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ |
31 | static void quit(int rc) |
32 | { |
33 | SDL_Quit(); |
34 | exit(rc); |
35 | } |
36 | |
37 | void* get_funcaddr(const char* p) |
38 | { |
39 | void* f=SDL_GL_GetProcAddress(p); |
40 | if (f) |
41 | { |
42 | return f; |
43 | } |
44 | else |
45 | { |
46 | printf("Unable to get function pointer for %s\n",p); |
47 | quit(1); |
48 | } |
49 | return NULL; |
50 | } |
51 | |
52 | typedef struct |
53 | { |
54 | void(APIENTRY*glBegin)(GLenum); |
55 | void(APIENTRY*glEnd)(); |
56 | void(APIENTRY*glVertex3f)(GLfloat, GLfloat, GLfloat); |
57 | void(APIENTRY*glClearColor)(GLfloat, GLfloat, GLfloat, GLfloat); |
58 | void(APIENTRY*glClear)(GLbitfield); |
59 | void(APIENTRY*glDisable)(GLenum); |
60 | void(APIENTRY*glEnable)(GLenum); |
61 | void(APIENTRY*glColor4ub)(GLubyte,GLubyte,GLubyte,GLubyte); |
62 | void(APIENTRY*glPointSize)(GLfloat); |
63 | void(APIENTRY*glHint)(GLenum,GLenum); |
64 | void(APIENTRY*glBlendFunc)(GLenum,GLenum); |
65 | void(APIENTRY*glMatrixMode)(GLenum); |
66 | void(APIENTRY*glLoadIdentity)(); |
67 | void(APIENTRY*glOrtho)(GLdouble,GLdouble,GLdouble,GLdouble,GLdouble,GLdouble); |
68 | void(APIENTRY*glRotatef)(GLfloat,GLfloat,GLfloat,GLfloat); |
69 | void(APIENTRY*glViewport)(GLint,GLint,GLsizei,GLsizei); |
70 | void(APIENTRY*glFogf)(GLenum,GLfloat); |
71 | } |
72 | glfuncs; |
73 | |
74 | void init_glfuncs(glfuncs* f) |
75 | { |
76 | f->glBegin=get_funcaddr("glBegin"); |
77 | f->glEnd=get_funcaddr("glEnd"); |
78 | f->glVertex3f=get_funcaddr("glVertex3f"); |
79 | f->glClearColor=get_funcaddr("glClearColor"); |
80 | f->glClear=get_funcaddr("glClear"); |
81 | f->glDisable=get_funcaddr("glDisable"); |
82 | f->glEnable=get_funcaddr("glEnable"); |
83 | f->glColor4ub=get_funcaddr("glColor4ub"); |
84 | f->glPointSize=get_funcaddr("glPointSize"); |
85 | f->glHint=get_funcaddr("glHint"); |
86 | f->glBlendFunc=get_funcaddr("glBlendFunc"); |
87 | f->glMatrixMode=get_funcaddr("glMatrixMode"); |
88 | f->glLoadIdentity=get_funcaddr("glLoadIdentity"); |
89 | f->glOrtho=get_funcaddr("glOrtho"); |
90 | f->glRotatef=get_funcaddr("glRotatef"); |
91 | f->glViewport=get_funcaddr("glViewport"); |
92 | f->glFogf=get_funcaddr("glFogf"); |
93 | } |
94 | |
95 | #define NB_PIXELS 1000 |
96 | |
97 | int main(int argc,char *argv[]) |
98 | { |
99 | glfuncs f; |
100 | int i; |
101 | SDL_Event event; |
102 | int done=0; |
103 | GLfloat pixels[NB_PIXELS*3]; |
104 | const char *gl_library = NULL; /* Use the default GL library */ |
105 | |
106 | if (argv[1]) { |
107 | gl_library = argv[1]; |
108 | } |
109 | |
110 | if (SDL_Init(SDL_INIT_VIDEO)<0) |
111 | { |
112 | printf("Unable to init SDL : %s\n",SDL_GetError()); |
113 | return(1); |
114 | } |
115 | |
116 | if (SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1)<0) |
117 | { |
118 | printf("Unable to set GL attribute : %s\n",SDL_GetError()); |
119 | quit(1); |
120 | } |
121 | |
122 | if (SDL_GL_LoadLibrary(gl_library)<0) |
123 | { |
124 | printf("Unable to dynamically open GL lib : %s\n",SDL_GetError()); |
125 | quit(1); |
126 | } |
127 | |
128 | if (SDL_SetVideoMode(640,480,0,SDL_OPENGL)==NULL) |
129 | { |
130 | printf("Unable to open video mode : %s\n",SDL_GetError()); |
131 | quit(1); |
132 | } |
133 | |
134 | /* Set the window manager title bar */ |
135 | SDL_WM_SetCaption( "SDL Dynamic OpenGL Loading Test", "testdyngl" ); |
136 | |
137 | init_glfuncs(&f); |
138 | |
139 | for(i=0;i<NB_PIXELS;i++) |
140 | { |
141 | pixels[3*i]=rand()%250-125; |
142 | pixels[3*i+1]=rand()%250-125; |
143 | pixels[3*i+2]=rand()%250-125; |
144 | } |
145 | |
146 | f.glViewport(0,0,640,480); |
147 | |
148 | f.glMatrixMode(GL_PROJECTION); |
149 | f.glLoadIdentity(); |
150 | f.glOrtho(-100,100,-100,100,-500,500); |
151 | |
152 | f.glMatrixMode(GL_MODELVIEW); |
153 | f.glLoadIdentity(); |
154 | |
155 | f.glEnable(GL_DEPTH_TEST); |
156 | f.glDisable(GL_TEXTURE_2D); |
157 | f.glEnable(GL_BLEND); |
158 | f.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); |
159 | |
160 | f.glClearColor(0.0f,0.0f,0.0f,0.0f); |
161 | f.glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); |
162 | |
163 | f.glEnable(GL_POINT_SMOOTH); |
164 | f.glHint(GL_POINT_SMOOTH_HINT,GL_NICEST); |
165 | f.glPointSize(5.0f); |
166 | f.glEnable(GL_FOG); |
167 | f.glFogf(GL_FOG_START,-500); |
168 | f.glFogf(GL_FOG_END,500); |
169 | f.glFogf(GL_FOG_DENSITY,0.005); |
170 | |
171 | do |
172 | { |
173 | f.glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); |
174 | |
175 | f.glRotatef(2.0,1.0,1.0,1.0); |
176 | f.glRotatef(1.0,0.0,1.0,1.0); |
177 | |
178 | f.glColor4ub(255,255,255,255); |
179 | f.glBegin(GL_POINTS); |
180 | for(i=0;i<NB_PIXELS;i++) |
181 | { |
182 | f.glVertex3f(pixels[3*i],pixels[3*i+1],pixels[3*i+2]); |
183 | } |
184 | f.glEnd(); |
185 | SDL_GL_SwapBuffers(); |
186 | |
187 | while(SDL_PollEvent(&event)) |
188 | { |
189 | if(event.type & SDL_KEYDOWN) |
190 | done=1; |
191 | } |
192 | |
193 | SDL_Delay(20); |
194 | } |
195 | while(!done); |
196 | |
197 | SDL_Quit(); |
198 | return 0; |
199 | } |
200 | |
201 | #else /* HAVE_OPENGL */ |
202 | |
203 | int main(int argc, char *argv[]) |
204 | { |
205 | printf("No OpenGL support on this system\n"); |
206 | return 1; |
207 | } |
208 | |
209 | #endif /* HAVE_OPENGL */ |