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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
|
/*
* Demo of off-screen Mesa rendering with 16-bit color channels.
* This requires the libOSMesa16.so library.
*
* Compile with something like this:
*
* gcc osdemo16.c -I../../include -L../../lib -lglut -lGLU -lOSMesa16 -lm -o osdemo16
*/
#include <stdio.h>
#include <stdlib.h>
#include "GL/osmesa.h"
#include "GL/glut.h"
#define SAVE_TARGA
#define WIDTH 400
#define HEIGHT 400
static void render_image( void )
{
GLfloat light_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 };
GLfloat red_mat[] = { 1.0, 0.2, 0.2, 1.0 };
GLfloat green_mat[] = { 0.2, 1.0, 0.2, 0.5 };
GLfloat blue_mat[] = { 0.2, 0.2, 1.0, 1.0 };
GLfloat white_mat[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat purple_mat[] = { 1.0, 0.2, 1.0, 1.0 };
GLUquadricObj *qobj = gluNewQuadric();
glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-2.5, 2.5, -2.5, 2.5, -10.0, 10.0);
glMatrixMode(GL_MODELVIEW);
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glPushMatrix();
glRotatef(20.0, 1.0, 0.0, 0.0);
#if 0
glPushMatrix();
glTranslatef(-0.75, 0.5, 0.0);
glRotatef(90.0, 1.0, 0.0, 0.0);
glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, red_mat );
glutSolidTorus(0.275, 0.85, 20, 20);
glPopMatrix();
#endif
/* red square */
glPushMatrix();
glTranslatef(0.0, -0.5, 0.0);
glRotatef(90, 1, 0.5, 0);
glScalef(3, 3, 3);
glDisable(GL_LIGHTING);
glColor4f(1, 0, 0, 0.5);
glBegin(GL_POLYGON);
glVertex2f(-1, -1);
glVertex2f( 1, -1);
glVertex2f( 1, 1);
glVertex2f(-1, 1);
glEnd();
glEnable(GL_LIGHTING);
glPopMatrix();
#if 0
/* green square */
glPushMatrix();
glTranslatef(0.0, 0.5, 0.1);
glDisable(GL_LIGHTING);
glColor3f(0, 1, 0);
glBegin(GL_POLYGON);
glVertex2f(-1, -1);
glVertex2f( 1, -1);
glVertex2f( 1, 1);
glVertex2f(-1, 1);
glEnd();
glEnable(GL_LIGHTING);
glPopMatrix();
/* blue square */
glPushMatrix();
glTranslatef(0.75, 0.5, 0.3);
glDisable(GL_LIGHTING);
glColor3f(0, 0, 0.5);
glBegin(GL_POLYGON);
glVertex2f(-1, -1);
glVertex2f( 1, -1);
glVertex2f( 1, 1);
glVertex2f(-1, 1);
glEnd();
glEnable(GL_LIGHTING);
glPopMatrix();
#endif
glPushMatrix();
glTranslatef(-0.75, -0.5, 0.0);
glRotatef(270.0, 1.0, 0.0, 0.0);
glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, green_mat );
glColor4f(0,1,0,0.5);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
gluCylinder(qobj, 1.0, 0.0, 2.0, 16, 1);
glDisable(GL_BLEND);
glPopMatrix();
glPushMatrix();
glTranslatef(0.75, 1.0, 1.0);
glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, blue_mat );
gluSphere(qobj, 1.0, 20, 20);
glPopMatrix();
glPopMatrix();
/* This is very important!!!
* Make sure buffered commands are finished!!!
*/
glFinish();
gluDeleteQuadric(qobj);
{
GLint r, g, b, a;
glGetIntegerv(GL_RED_BITS, &r);
glGetIntegerv(GL_GREEN_BITS, &g);
glGetIntegerv(GL_BLUE_BITS, &b);
glGetIntegerv(GL_ALPHA_BITS, &a);
printf("channel sizes: %d %d %d %d\n", r, g, b, a);
}
}
static void
write_targa(const char *filename, const GLushort *buffer, int width, int height)
{
FILE *f = fopen( filename, "w" );
if (f) {
int i, x, y;
const GLushort *ptr = buffer;
printf ("osdemo, writing tga file \n");
fputc (0x00, f); /* ID Length, 0 => No ID */
fputc (0x00, f); /* Color Map Type, 0 => No color map included */
fputc (0x02, f); /* Image Type, 2 => Uncompressed, True-color Image */
fputc (0x00, f); /* Next five bytes are about the color map entries */
fputc (0x00, f); /* 2 bytes Index, 2 bytes length, 1 byte size */
fputc (0x00, f);
fputc (0x00, f);
fputc (0x00, f);
fputc (0x00, f); /* X-origin of Image */
fputc (0x00, f);
fputc (0x00, f); /* Y-origin of Image */
fputc (0x00, f);
fputc (WIDTH & 0xff, f); /* Image Width */
fputc ((WIDTH>>8) & 0xff, f);
fputc (HEIGHT & 0xff, f); /* Image Height */
fputc ((HEIGHT>>8) & 0xff, f);
fputc (0x18, f); /* Pixel Depth, 0x18 => 24 Bits */
fputc (0x20, f); /* Image Descriptor */
fclose(f);
f = fopen( filename, "ab" ); /* reopen in binary append mode */
for (y=height-1; y>=0; y--) {
for (x=0; x<width; x++) {
i = (y*width + x) * 4;
/* just write 8 high bits */
fputc(ptr[i+2] >> 8, f); /* write blue */
fputc(ptr[i+1] >> 8, f); /* write green */
fputc(ptr[i] >> 8, f); /* write red */
}
}
}
}
static void
write_ppm(const char *filename, const GLushort *buffer, int width, int height)
{
const int binary = 0;
FILE *f = fopen( filename, "w" );
if (f) {
int i, x, y;
const GLushort *ptr = buffer;
if (binary) {
fprintf(f,"P6\n");
fprintf(f,"# ppm-file created by osdemo.c\n");
fprintf(f,"%i %i\n", width,height);
fprintf(f,"255\n");
fclose(f);
f = fopen( filename, "ab" ); /* reopen in binary append mode */
for (y=height-1; y>=0; y--) {
for (x=0; x<width; x++) {
i = (y*width + x) * 4;
/* just write 8 high bits */
fputc(ptr[i] >> 8, f); /* write red */
fputc(ptr[i+1] >> 8, f); /* write green */
fputc(ptr[i+2] >> 8, f); /* write blue */
}
}
}
else {
/*ASCII*/
int counter = 0;
fprintf(f,"P3\n");
fprintf(f,"# ascii ppm file created by osdemo.c\n");
fprintf(f,"%i %i\n", width, height);
fprintf(f,"255\n");
for (y=height-1; y>=0; y--) {
for (x=0; x<width; x++) {
i = (y*width + x) * 4;
/* just write 8 high bits */
fprintf(f, " %3d %3d %3d", ptr[i] >> 8, ptr[i+1] >> 8, ptr[i+2] >> 8);
counter++;
if (counter % 5 == 0)
fprintf(f, "\n");
}
}
}
fclose(f);
}
}
int main( int argc, char *argv[] )
{
GLushort *buffer;
/* Create an RGBA-mode context */
#if OSMESA_MAJOR_VERSION * 100 + OSMESA_MINOR_VERSION >= 305
/* specify Z, stencil, accum sizes */
OSMesaContext ctx = OSMesaCreateContextExt( GL_RGBA, 16, 0, 0, NULL );
#else
OSMesaContext ctx = OSMesaCreateContext( GL_RGBA, NULL );
#endif
if (!ctx) {
printf("OSMesaCreateContext failed!\n");
return 0;
}
/* Allocate the image buffer */
buffer = (GLushort *) malloc( WIDTH * HEIGHT * 4 * sizeof(GLushort));
if (!buffer) {
printf("Alloc image buffer failed!\n");
return 0;
}
/* Bind the buffer to the context and make it current */
if (!OSMesaMakeCurrent( ctx, buffer, GL_UNSIGNED_SHORT, WIDTH, HEIGHT )) {
printf("OSMesaMakeCurrent failed!\n");
return 0;
}
render_image();
if (argc>1) {
#ifdef SAVE_TARGA
write_targa(argv[1], buffer, WIDTH, HEIGHT);
#else
write_ppm(argv[1], buffer, WIDTH, HEIGHT);
#endif
}
else {
printf("Specify a filename if you want to make an image file\n");
}
printf("all done\n");
/* free the image buffer */
free( buffer );
/* destroy the context */
OSMesaDestroyContext( ctx );
return 0;
}
|
