1
2 /*
3 * glReadPixels and glCopyPixels test
4 *
5 * Brian Paul March 1, 2000 This file is in the public domain.
6 */
7
8 #include <assert.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <math.h>
12 #include <string.h>
13 #include "glut_wrap.h"
14
15 #include "readtex.h"
16
17 #define IMAGE_FILE DEMOS_DATA_DIR "girl.rgb"
18
19 static int ImgWidth, ImgHeight;
20 static int WinWidth, WinHeight;
21 static GLenum ImgFormat;
22 static GLubyte *Image = NULL;
23
24 static int APosX, APosY; /* simple drawpixels */
25 static int BPosX, BPosY; /* read/draw pixels */
26 static int CPosX, CPosY; /* copypixels */
27
28 static GLboolean DrawFront = GL_FALSE;
29 static GLboolean ScaleAndBias = GL_FALSE;
30 static GLboolean Benchmark = GL_FALSE;
31 static GLboolean Triangle = GL_FALSE;
32 static GLubyte *TempImage = NULL;
33
34 #define COMBO 1
35 #if COMBO == 0
36 #define ReadFormat ImgFormat
37 #define ReadType GL_UNSIGNED_BYTE
38 #elif COMBO == 1
39 static GLenum ReadFormat = GL_RGBA;
40 static GLenum ReadType = GL_UNSIGNED_BYTE;
41 #elif COMBO == 2
42 static GLenum ReadFormat = GL_RGB;
43 static GLenum ReadType = GL_UNSIGNED_BYTE;
44 #elif COMBO == 3
45 static GLenum ReadFormat = GL_RGB;
46 static GLenum ReadType = GL_UNSIGNED_SHORT_5_6_5;
47 #elif COMBO == 4
48 static GLenum ReadFormat = GL_RGBA;
49 static GLenum ReadType = GL_UNSIGNED_SHORT_1_5_5_5_REV;
50 #elif COMBO == 5
51 static GLenum ReadFormat = GL_BGRA;
52 static GLenum ReadType = GL_UNSIGNED_SHORT_5_5_5_1;
53 #elif COMBO == 6
54 static GLenum ReadFormat = GL_BGRA;
55 static GLenum ReadType = GL_UNSIGNED_SHORT_4_4_4_4_REV;
56 #elif COMBO == 7
57 static GLenum ReadFormat = GL_RGBA;
58 static GLenum ReadType = GL_HALF_FLOAT_ARB;
59 #undef GL_OES_read_format
60 #endif
61
62
63 static void
Reset(void)64 Reset( void )
65 {
66 APosX = 5; APosY = 20;
67 BPosX = APosX + ImgWidth + 5; BPosY = 20;
68 CPosX = BPosX + ImgWidth + 5; CPosY = 20;
69 }
70
71
72 static void
PrintString(const char * s)73 PrintString(const char *s)
74 {
75 while (*s) {
76 glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
77 s++;
78 }
79 }
80
81
82 static void
SetupPixelTransfer(GLboolean invert)83 SetupPixelTransfer(GLboolean invert)
84 {
85 if (invert) {
86 glPixelTransferf(GL_RED_SCALE, -1.0);
87 glPixelTransferf(GL_RED_BIAS, 1.0);
88 glPixelTransferf(GL_GREEN_SCALE, -1.0);
89 glPixelTransferf(GL_GREEN_BIAS, 1.0);
90 glPixelTransferf(GL_BLUE_SCALE, -1.0);
91 glPixelTransferf(GL_BLUE_BIAS, 1.0);
92 }
93 else {
94 glPixelTransferf(GL_RED_SCALE, 1.0);
95 glPixelTransferf(GL_RED_BIAS, 0.0);
96 glPixelTransferf(GL_GREEN_SCALE, 1.0);
97 glPixelTransferf(GL_GREEN_BIAS, 0.0);
98 glPixelTransferf(GL_BLUE_SCALE, 1.0);
99 glPixelTransferf(GL_BLUE_BIAS, 0.0);
100 }
101 }
102
103
104 /**
105 * Exercise Pixel Pack parameters by reading the image in four pieces.
106 */
107 static void
ComplexReadPixels(GLint x,GLint y,GLsizei width,GLsizei height,GLenum format,GLenum type,GLvoid * pixels)108 ComplexReadPixels(GLint x, GLint y, GLsizei width, GLsizei height,
109 GLenum format, GLenum type, GLvoid *pixels)
110 {
111 const GLsizei width0 = width / 2;
112 const GLsizei width1 = width - width0;
113 const GLsizei height0 = height / 2;
114 const GLsizei height1 = height - height0;
115
116 glPixelStorei(GL_PACK_ROW_LENGTH, width);
117
118 /* lower-left quadrant */
119 glReadPixels(x, y, width0, height0, format, type, pixels);
120
121 /* lower-right quadrant */
122 glPixelStorei(GL_PACK_SKIP_PIXELS, width0);
123 glReadPixels(x + width0, y, width1, height0, format, type, pixels);
124
125 /* upper-left quadrant */
126 glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
127 glPixelStorei(GL_PACK_SKIP_ROWS, height0);
128 glReadPixels(x, y + height0, width0, height1, format, type, pixels);
129
130 /* upper-right quadrant */
131 glPixelStorei(GL_PACK_SKIP_PIXELS, width0);
132 glPixelStorei(GL_PACK_SKIP_ROWS, height0);
133 glReadPixels(x + width0, y + height0, width1, height1, format, type, pixels);
134
135 /* restore defaults */
136 glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
137 glPixelStorei(GL_PACK_SKIP_ROWS, 0);
138 glPixelStorei(GL_PACK_ROW_LENGTH, ImgWidth);
139 }
140
141
142
143 static void
Display(void)144 Display( void )
145 {
146 glClearColor(.3, .3, .3, 1);
147 glClear( GL_COLOR_BUFFER_BIT );
148
149 glRasterPos2i(5, ImgHeight+25);
150 PrintString("f = toggle front/back s = toggle scale/bias b = benchmark");
151
152 /* draw original image */
153 glRasterPos2i(APosX, 5);
154 PrintString("Original");
155 if (!Triangle) {
156 glRasterPos2i(APosX, APosY);
157 glEnable(GL_DITHER);
158 SetupPixelTransfer(GL_FALSE);
159 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
160 glDrawPixels(ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image);
161 }
162 else {
163 float z = 0;
164
165 glViewport(APosX, APosY, ImgWidth, ImgHeight);
166 glMatrixMode( GL_PROJECTION );
167 glLoadIdentity();
168 glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);
169 glDisable(GL_CULL_FACE);
170
171 /* Red should never be seen
172 */
173 glBegin(GL_POLYGON);
174 glColor3f(1,0,0);
175 glVertex3f(-2, -2, z);
176 glVertex3f(-2, 2, z);
177 glVertex3f(2, 2, z);
178 glVertex3f(2, -2, z);
179 glEnd();
180
181 /* Blue background
182 */
183 glBegin(GL_POLYGON);
184 glColor3f(.5,.5,1);
185 glVertex3f(-1, -1, z);
186 glVertex3f(-1, 1, z);
187 glVertex3f(1, 1, z);
188 glVertex3f(1, -1, z);
189 glEnd();
190
191 /* Triangle
192 */
193 glBegin(GL_TRIANGLES);
194 glColor3f(.8,0,0);
195 glVertex3f(-0.9, -0.9, z);
196 glColor3f(0,.9,0);
197 glVertex3f( 0.9, -0.9, z);
198 glColor3f(0,0,.7);
199 glVertex3f( 0.0, 0.9, z);
200 glEnd();
201
202 glColor3f(1,1,1);
203
204 glViewport( 0, 0, WinWidth, WinHeight );
205 glMatrixMode( GL_PROJECTION );
206 glLoadIdentity();
207 glOrtho( 0.0, WinWidth, 0.0, WinHeight, -1.0, 1.0 );
208 }
209
210 /* might try alignment=4 here for testing */
211 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
212 glPixelStorei(GL_PACK_ALIGNMENT, 1);
213
214 /* do readpixels, drawpixels */
215 glRasterPos2i(BPosX, 5);
216 PrintString("Read/DrawPixels");
217 SetupPixelTransfer(ScaleAndBias);
218 if (Benchmark) {
219 GLint reads = 0;
220 GLint endTime;
221 GLint startTime = glutGet(GLUT_ELAPSED_TIME);
222 GLdouble seconds, mpixels, mpixelsPerSecond;
223 printf("Benchmarking...\n");
224 do {
225 glReadPixels(APosX, APosY, ImgWidth, ImgHeight,
226 ReadFormat, ReadType, TempImage);
227 reads++;
228 endTime = glutGet(GLUT_ELAPSED_TIME);
229 } while (endTime - startTime < 4000); /* 4 seconds */
230 seconds = (double) (endTime - startTime) / 1000.0;
231 mpixels = reads * (ImgWidth * ImgHeight / (1000.0 * 1000.0));
232 mpixelsPerSecond = mpixels / seconds;
233 printf("Result: %d reads in %f seconds = %f Mpixels/sec\n",
234 reads, seconds, mpixelsPerSecond);
235 Benchmark = GL_FALSE;
236 }
237 else {
238 /* clear the temporary image to white (helpful for debugging */
239 memset(TempImage, 255, ImgWidth * ImgHeight * 4);
240 #if 1
241 glReadPixels(APosX, APosY, ImgWidth, ImgHeight,
242 ReadFormat, ReadType, TempImage);
243 (void) ComplexReadPixels;
244 #else
245 /* you might use this when debugging */
246 ComplexReadPixels(APosX, APosY, ImgWidth, ImgHeight,
247 ReadFormat, ReadType, TempImage);
248 #endif
249 }
250 glRasterPos2i(BPosX, BPosY);
251 glDisable(GL_DITHER);
252 SetupPixelTransfer(GL_FALSE);
253 glDrawPixels(ImgWidth, ImgHeight, ReadFormat, ReadType, TempImage);
254
255 /* do copypixels */
256 glRasterPos2i(CPosX, 5);
257 PrintString("CopyPixels");
258 glRasterPos2i(CPosX, CPosY);
259 glDisable(GL_DITHER);
260 SetupPixelTransfer(ScaleAndBias);
261 glCopyPixels(APosX, APosY, ImgWidth, ImgHeight, GL_COLOR);
262
263 if (!DrawFront)
264 glutSwapBuffers();
265 else
266 glFinish();
267 }
268
269
270 static void
Reshape(int width,int height)271 Reshape( int width, int height )
272 {
273 WinWidth = width;
274 WinHeight = height;
275
276 glViewport( 0, 0, width, height );
277 glMatrixMode( GL_PROJECTION );
278 glLoadIdentity();
279 glOrtho( 0.0, width, 0.0, height, -1.0, 1.0 );
280 glMatrixMode( GL_MODELVIEW );
281 glLoadIdentity();
282 }
283
284
285 static void
Key(unsigned char key,int x,int y)286 Key( unsigned char key, int x, int y )
287 {
288 (void) x;
289 (void) y;
290 switch (key) {
291 case 'b':
292 Benchmark = GL_TRUE;
293 break;
294 case 't':
295 Triangle = !Triangle;
296 break;
297 case 's':
298 ScaleAndBias = !ScaleAndBias;
299 break;
300 case 'f':
301 DrawFront = !DrawFront;
302 if (DrawFront) {
303 glDrawBuffer(GL_FRONT);
304 glReadBuffer(GL_FRONT);
305 }
306 else {
307 glDrawBuffer(GL_BACK);
308 glReadBuffer(GL_BACK);
309 }
310 printf("glDrawBuffer(%s)\n", DrawFront ? "GL_FRONT" : "GL_BACK");
311 break;
312 case 27:
313 exit(0);
314 break;
315 }
316 glutPostRedisplay();
317 }
318
319
320 static void
Init(GLboolean ciMode)321 Init( GLboolean ciMode )
322 {
323 GLboolean have_read_format = GL_FALSE;
324
325 printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
326 printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
327
328 Image = LoadRGBImage( IMAGE_FILE, &ImgWidth, &ImgHeight, &ImgFormat );
329 if (!Image) {
330 printf("Couldn't read %s\n", IMAGE_FILE);
331 exit(0);
332 }
333
334 if (ciMode) {
335 /* Convert RGB image to grayscale */
336 GLubyte *indexImage = (GLubyte *) malloc( ImgWidth * ImgHeight );
337 GLint i;
338 for (i=0; i<ImgWidth*ImgHeight; i++) {
339 int gray = Image[i*3] + Image[i*3+1] + Image[i*3+2];
340 indexImage[i] = gray / 3;
341 }
342 free(Image);
343 Image = indexImage;
344 ImgFormat = GL_COLOR_INDEX;
345
346 for (i=0;i<255;i++) {
347 float g = i / 255.0;
348 glutSetColor(i, g, g, g);
349 }
350 }
351
352 #ifdef GL_OES_read_format
353 if ( glutExtensionSupported( "GL_OES_read_format" ) ) {
354 glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE_OES, (GLint *) &ReadType);
355 glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES, (GLint *) &ReadFormat);
356
357 have_read_format = GL_TRUE;
358 }
359 #endif
360
361 printf( "GL_OES_read_format %ssupported. "
362 "Using type / format = 0x%04x / 0x%04x\n",
363 (have_read_format) ? "" : "not ",
364 ReadType, ReadFormat );
365
366 printf("Loaded %d by %d image\n", ImgWidth, ImgHeight );
367
368 glPixelStorei(GL_UNPACK_ROW_LENGTH, ImgWidth);
369 glPixelStorei(GL_PACK_ROW_LENGTH, ImgWidth);
370
371 Reset();
372
373 /* allocate large TempImage to store and image data type, plus an
374 * extra 1KB in case we're tinkering with pack alignment.
375 */
376 TempImage = (GLubyte *) malloc(ImgWidth * ImgHeight * 4 * 4
377 + 1000);
378 assert(TempImage);
379 }
380
381
382 int
main(int argc,char * argv[])383 main( int argc, char *argv[] )
384 {
385 GLboolean ciMode = GL_FALSE;
386 glutInitWindowSize( 750, 250 );
387 glutInit( &argc, argv );
388 if (argc > 1 && strcmp(argv[1], "-ci")==0) {
389 ciMode = GL_TRUE;
390 }
391 if (ciMode)
392 glutInitDisplayMode( GLUT_INDEX | GLUT_DOUBLE );
393 else
394 glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
395 glutCreateWindow(argv[0]);
396 Init(ciMode);
397 glutReshapeFunc( Reshape );
398 glutKeyboardFunc( Key );
399 glutDisplayFunc( Display );
400 glutMainLoop();
401 return 0;
402 }
403