OpenGL Programming Guide Second Edition - Niksula

More documents

Recommendations

Info

processedfragment is drawn into the appropriate buffer, where it has finally advanced to be a pixel and achieved its final resting place. OpenGL−Related Libraries OpenGL provides a powerful but primitive set of rendering commands, and all higher−level drawing must be done in terms of these commands. Also, OpenGL programs have to use the underlying mechanisms of the windowing system. A number of libraries exist to allow you to simplify your programming tasks, including the following: The OpenGL Utility Library (GLU) contains several routines that use lower−level OpenGL commands to perform such tasks as setting up matrices for specific viewing orientations and projections, performing polygon tessellation, and rendering surfaces. This library is provided as part of every OpenGL implementation. Portions of the GLU are described in the OpenGL Reference Manual. The more useful GLU routines are described in this guide, where they’re relevant to the topic being discussed, such as in all of Chapter 11 and in the section "The GLU NURBS Interface" in Chapter 12. GLU routines use the prefix glu. For every window system, there is a library that extends the functionality of that window system to support OpenGL rendering. For machines that use the X Window System, the OpenGL Extension to the X Window System (GLX) is provided as an adjunct to OpenGL. GLX routines use the prefix glX. For Microsoft Windows, the WGL routines provide the Windows to OpenGL interface. All WGL routines use the prefix wgl. For IBM OS/2, the PGL is the Presentation Manager to OpenGL interface, and its routines use the prefix pgl. All these window system extension libraries are described in more detail in both Appendix C. In addition, the GLX routines are also described in the OpenGL Reference Manual. The OpenGL Utility Toolkit (GLUT) is a window system−independent toolkit, written by Mark Kilgard, to hide the complexities of differing window system APIs. GLUT is the subject of the next section, and it’s described in more detail in Mark Kilgard’s book OpenGL Programming for the X Window System (ISBN 0−201−48359−9). GLUT routines use the prefix glut. "How to Obtain the Sample Code" in the Preface describes how to obtain the source code for GLUT, using ftp. Open Inventor is an object−oriented toolkit based on OpenGL which provides objects and methods for creating interactive three−dimensional graphics applications. Open Inventor, which is written in C++, provides prebuilt objects and a built−in event model for user interaction, high−level application components for creating and editing three−dimensional scenes, and the ability to print objects and exchange data in other graphics formats. Open Inventor is separate from OpenGL. Include Files For all OpenGL applications, you want to include the gl.h header file in every file. Almost all OpenGL applications use GLU, the aforementioned OpenGL Utility Library, which requires inclusion of the glu.h header file. So almost every OpenGL source file begins with #include #include OpenGL Programming Guide − Chapter 1, Introduction to OpenGL − 10
If you are directly accessing a window interface library to support OpenGL, such as GLX, AGL, PGL, or WGL, you must include additional header files. For example, if you are calling GLX, you may need to add these lines to your code #include #include If you are using GLUT for managing your window manager tasks, you should include #include Note that glut.h includes gl.h, glu.h, and glx.h automatically, so including all three files is redundant. GLUT for Microsoft Windows includes the appropriate header file to access WGL. GLUT, the OpenGL Utility Toolkit As you know, OpenGL contains rendering commands but is designed to be independent of any window system or operating system. Consequently, it contains no commands for opening windows or reading events from the keyboard or mouse. Unfortunately, it’s impossible to write a complete graphics program without at least opening a window, and most interesting programs require a bit of user input or other services from the operating system or window system. In many cases, complete programs make the most interesting examples, so this book uses GLUT to simplify opening windows, detecting input, and so on. If you have an implementation of OpenGL and GLUT on your system, the examples in this book should run without change when linked with them. In addition, since OpenGL drawing commands are limited to those that generate simple geometric primitives (points, lines, and polygons), GLUT includes several routines that create more complicated three−dimensional objects such as a sphere, a torus, and a teapot. This way, snapshots of program output can be interesting to look at. (Note that the OpenGL Utility Library, GLU, also has quadrics routines that create some of the same three−dimensional objects as GLUT, such as a sphere, cylinder, or cone.) GLUT may not be satisfactory for full−featured OpenGL applications, but you may find it a useful starting point for learning OpenGL. The rest of this section briefly describes a small subset of GLUT routines so that you can follow the programming examples in the rest of this book. (See Appendix D for more details about this subset of GLUT, or see Chapters 4 and 5 of OpenGL Programming for the X Window System for information about the rest of GLUT.) Window Management Five routines perform tasks necessary to initialize a window. glutInit(int *argc, char **argv) initializes GLUT and processes any command line arguments (for X, this would be options like −display and −geometry). glutInit() should be called before any other GLUT routine. glutInitDisplayMode(unsigned int mode) specifies whether to use an RGBA or color−index color model. You can also specify whether you want a single− or double−buffered window. (If you’re working in color−index mode, you’ll want to load certain colors into the color map; use glutSetColor() to do this.) Finally, you can use this routine to indicate that you want the window to have an associated depth, stencil, and/or accumulation buffer. For example, if you want a window with double buffering, the RGBA color model, and a depth buffer, you might call OpenGL Programming Guide − Chapter 1, Introduction to OpenGL − 11
Page 1 and 2: OpenGL Programming Guide Second Edi
Page 3 and 4: Examples of Composing Several Trans
Page 5 and 6: Bitmaps and Fonts The Current Raste
Page 7 and 8: Chapter 12 Evaluators and NURBS Pre
Page 9 and 10: Implementation−Dependent Pixel De
Page 11 and 12: Rotation Perspective Projection Ort
Page 13 and 14: depth−cuing diffuse directional l
Page 15 and 16: RGBA mode server shading shininess
Page 17 and 18: To Tom Doeppner and Andy van Dam, w
Page 19 and 20: textures onto three−dimensional o
Page 21 and 22: geometry). Even if you have little
Page 23 and 24: Acknowledgments The second edition
Page 25 and 26: Chapter 1 Introduction to OpenGL Ch
Page 27 and 28: of motion. "Plate 8" shows the scen
Page 29 and 30: } glVertex3f (0.25, 0.75, 0.0); glE
Page 31 and 32: OpenGL as a State Machine OpenGL is
Page 33: is enabled and the primitive is a p
Page 37 and 38: glVertex3f (0.75, 0.75, 0.0); glVer
Page 39 and 40: human eye is only so good. The key
Page 41 and 42: Figure 1−3 Double−Buffered Rota
Page 43 and 44: Chapter 2 State Management and Draw
Page 45 and 46: appropriate size and location for a
Page 47 and 48: Chapter 5 for details on these topi
Page 49 and 50: Example 2−1 Reshape Callback Func
Page 51 and 52: See Figure 2−3 for some examples
Page 53 and 54: glVertex4f(2.3, 1.0, −2.2, 2.0);
Page 55 and 56: GL_LINES Draws a series of unconnec
Page 57 and 58: ones in blue, despite the extra col
Page 59 and 60: void glLineWidth(GLfloat width); Se
Page 61 and 62: void display(void) { int i; glClear
Page 63 and 64: GL_FILL to indicate whether the pol
Page 65 and 66: Figure 2−10 Constructing a Polygo
Page 67 and 68: 0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55,
Page 69 and 70: glPolygonMode(GL_FRONT_AND_BACK, GL
Page 71 and 72: Figure 2−14 Six Sides; Eight Shar
Page 73 and 74: void glEdgeFlagPointer(GLsizei stri
Page 75 and 76: glEnableClientState (GL_VERTEX_ARRA
Page 77 and 78: process as few as eight vertices. (
Page 79 and 80: } else glColorPointer(sc, tc, str,
Page 81 and 82: GL_ALL_ATTRIB_BITS −− GL_COLOR_
Page 83 and 84: glBegin(GL_LINE_STRIP); for (i = 0;
Page 85 and 86:
} out[0] = v1[1]*v2[2] − v1[2]*v2
Page 87 and 88:
} } for (i = 0; i < 3; i++) { } v12
Page 89 and 90:
Chapter 3 Viewing Chapter Objective
Page 91 and 92:
the following. 1. Set up your tripo
Page 93 and 94:
program, not necessarily the order
Page 95 and 96:
} glViewport (0, 0, (GLsizei) w, (G
Page 97 and 98:
interior spaces look when viewed fr
Page 99 and 100:
Philosophy" in Chapter 7.) (OpenGL
Page 101 and 102:
x−axis), if you want the object t
Page 103 and 104:
shown in Figure 3−6. Figure 3−6
Page 105 and 106:
glLoadIdentity(); glScalef(1.5, 0.5
Page 107 and 108:
Figure 3−10 Separating the Viewpo
Page 109 and 110:
Figure 3−12 Using gluLookAt() So,
Page 111 and 112:
glMatrixMode(GL_PROJECTION); glLoad
Page 113 and 114:
GLdouble near, GLdouble far); Creat
Page 115 and 116:
planes and locate them wherever you
Page 117 and 118:
(Chapter 10 discusses the depth buf
Page 119 and 120:
{ } double radtheta, degtheta; radt
Page 121 and 122:
Figure 3−21 Pushing and Popping t
Page 123 and 124:
Advanced If you know enough mathema
Page 125 and 126:
* clip left half −− x < 0 */ }
Page 127 and 128:
#include #include #include stati
Page 129 and 130:
Figure 3−25 Robot Arm You can use
Page 131 and 132:
} } case ‘S’: shoulder = (shoul
Page 133 and 134:
#include #include #include #incl
Page 135 and 136:
Chapter 4 Color Chapter Objectives
Page 137 and 138:
is called the color buffer. The siz
Page 139 and 140:
number of bitplanes, 0.0 specifies
Page 141 and 142:
Figure 4−4 A Color Map A painter
Page 143 and 144:
mode. Then you must control the vis
Page 145 and 146:
GL_FLAT. With flat shading, the col
Page 147 and 148:
independent quad 4i Table 4−2 How
Page 149 and 150:
"Real−World and OpenGL Lighting"
Page 151 and 152:
desire a more accurate (or just dif
Page 153 and 154:
Example 5−1 accomplishes these ta
Page 155 and 156:
Example 5−1, the only element of
Page 157 and 158:
GLfloat light_ambient[] = { 0.0, 0.
Page 159 and 160:
Figure 5−2 GL_SPOT_CUTOFF Paramet
Page 161 and 162:
A light position that remains fixed
Page 163 and 164:
*/ void display(void) { } GLfloat p
Page 165 and 166:
} gluLookAt (ex, ey, ez, 0.0, 0.0,
Page 167 and 168:
it doesn’t matter what the back
Page 169 and 170:
glMaterialfv(GL_FRONT_AND_BACK, GL_
Page 171 and 172:
glTranslatef (1.25, 3.0, 0.0); glMa
Page 173 and 174:
void display(void) { } glClear(GL_C
Page 175 and 176:
colors when in RGBA mode. (See "The
Page 177 and 178:
The diffuse term needs to take into
Page 179 and 180:
of using this color ramp with a sin
Page 181 and 182:
drawn in a window on the screen? Wh
Page 183 and 184:
To blend three different images equ
Page 185 and 186:
#include static int leftFirst = GL
Page 187 and 188:
already in the framebuffer (the des
Page 189 and 190:
} glPushMatrix (); glTranslatef (0.
Page 191 and 192:
Figure 6−2 Aliased and Antialiase
Page 193 and 194:
#include static float rotAngle = 0
Page 195 and 196:
} glutDisplayFunc (display); glutMa
Page 197 and 198:
} } rotAngle += 20.; if (rotAngle >
Page 199 and 200:
#include #include #include #incl
Page 201 and 202:
{ } switch (key) { } case ‘t’:
Page 203 and 204:
} } glFogf (GL_FOG_DENSITY, 0.35);
Page 205 and 206:
In these three equations, z is the
Page 207 and 208:
} glFogf (GL_FOG_START, 1.0); glFog
Page 209 and 210:
where m is the maximum depth slope
Page 211 and 212:
Chapter 7 Display Lists Chapter Obj
Page 213 and 214:
} } } } glEnd(); glVertex3f(x, y, z
Page 215 and 216:
glEnd() calls are stored in the dis
Page 217 and 218:
implementation may be able to perfo
Page 219 and 220:
} return 0; The glTranslatef() rout
Page 221 and 222:
arrays, so these operations can be
Page 223 and 224:
mechanism requires that you put the
Page 225 and 226:
} CP; int type; CP Adata[] = { }; {
Page 227 and 228:
} glTranslatef(10.0, 30.0, 0.0); pr
Page 229 and 230:
glEndList(); If you use the display
Page 231 and 232:
Chapter 8 Drawing Pixels, Bitmaps,
Page 233 and 234:
0xff, 0x00, 0xff, 0x00, 0xc0, 0x00,
Page 235 and 236:
Drawing the Bitmap Once you’ve se
Page 237 and 238:
an offset to every entry in the str
Page 239 and 240:
{0x00, 0x00, 0x7e, 0xe7, 0xc3, 0xc3
Page 241 and 242:
} glutMainLoop(); return 0; Images
Page 243 and 244:
component, followed by a blue color
Page 245 and 246:
current drawing buffers with glDraw
Page 247 and 248:
Figure 8−8 glCopyTexImage*() and
Page 249 and 250:
Figure 8−9 *SKIP_ROWS, *SKIP_PIXE
Page 251 and 252:
Pixel Mapping All the color compone
Page 253 and 254:
} int i, j, c; for (i = 0; i < chec
Page 255 and 256:
} glutMotionFunc(motion); glutMainL
Page 257 and 258:
3. Each component (R, G, B, A, or d
Page 259 and 260:
5. If the storage format is one of
Page 261 and 262:
lend a texture color with the surfa
Page 263 and 264:
An Overview and an Example This sec
Page 265 and 266:
#define checkImageHeight 64 static
Page 267 and 268:
} init(); glutDisplayFunc(display);
Page 269 and 270:
texture of internal format GL_R3_G3
Page 271 and 272:
Note: There is one major limitation
Page 273 and 274:
{ } switch (key) { } case ‘s’:
Page 275 and 276:
GL_READ_BUFFER and are processed ex
Page 277 and 278:
#include #include #include GLuby
Page 279 and 280:
} glTexEnvf(GL_TEXTURE_ENV, GL_TEXT
Page 281 and 282:
Figure 9−5 Texture Magnification
Page 283 and 284:
eturned in textureNames do not have
Page 285 and 286:
} GL_NEAREST); glTexParameteri(GL_T
Page 287 and 288:
texture objects. void glPrioritizeT
Page 289 and 290:
lended with the texture color in a
Page 291 and 292:
the surface, the more distortion of
Page 293 and 294:
Figure 9−8 Clamping a Texture You
Page 295 and 296:
Initially in Example 9−6, equally
Page 297 and 298:
} glFlush(); void reshape(int w, in
Page 299 and 300:
calculated only at the time they’
Page 301 and 302:
indexed by s’/q’ and t’/q’
Page 303 and 304:
Figure 10−1 Region Occupied by a
Page 305 and 306:
you might use them for saving an im
Page 307 and 308:
can be one of the following: GL_FRO
Page 309 and 310:
7. Logical operation Each of these
Page 311 and 312:
You can obtain the values for all s
Page 313 and 314:
} glPushMatrix(); glRotatef (90.0,
Page 315 and 316:
pixel appears, it’s drawn only if
Page 317 and 318:
Table 10−4 Sixteen Logical Operat
Page 319 and 320:
} xwsize = right − left; ywsize =
Page 321 and 322:
} glutSolidSphere (1.0, 16, 16); gl
Page 323 and 324:
} glFlush(); void reshape(int w, in
Page 325 and 326:
Example 10−5 Depth−of−Field E
Page 327 and 328:
} } glAccum (GL_RETURN, 1.0); glFlu
Page 329 and 330:
Chapter 11 Tessellators and Quadric
Page 331 and 332:
hurts to be tidy. Tessellation Call
Page 333 and 334:
void errorCallback(GLenum errorCode
Page 335 and 336:
GLdouble value); For the tessellati
Page 337 and 338:
The winding rules are also designed
Page 339 and 340:
for several vertices may not get th
Page 341 and 342:
The GLU provides a routine for obta
Page 343 and 344:
GLUquadricObj* gluNewQuadric (void)
Page 345 and 346:
sweepAngle are measured in degrees,
Page 347 and 348:
} glTranslatef(0.0, 2.0, 0.0); glPu
Page 349 and 350:
Chapter 12 Evaluators and NURBS Cha
Page 351 and 352:
vertices can be used like any other
Page 353 and 354:
} A cubic Bézier curve is describe
Page 355 and 356:
You can use glEvalCoord1() with any
Page 357 and 358:
}; {0.5, −1.5, −1.0}, {1.5, −
Page 359 and 360:
Figure 12−3 Lit, Shaded Bézier S
Page 361 and 362:
} for (i = 0; i < imageWidth; i++)
Page 363 and 364:
once with the control points (ratio
Page 365 and 366:
} glRotatef(330.0, 1.,0.,0.); glSca
Page 367 and 368:
The default value for GLU_DISPLAY_M
Page 369 and 370:
points, respectively. You might als
Page 371 and 372:
Figure 12−6 Trimmed NURBS Surface
Page 373 and 374:
Chapter 13 Selection and Feedback C
Page 375 and 376:
As mentioned in the previous sectio
Page 377 and 378:
void drawTriangle (GLfloat x1, GLfl
Page 379 and 380:
} glPushMatrix (); glMatrixMode (GL
Page 381 and 382:
different components of a primitive
Page 383 and 384:
glMatrixMode (GL_PROJECTION); glPus
Page 385 and 386:
} glPopMatrix(); /* draw last two w
Page 387 and 388:
} if (mode == GL_SELECT) glLoadName
Page 389 and 390:
} return 0; Try This Modify Example
Page 391 and 392:
hand, selection in three dimensions
Page 393 and 394:
A Feedback Example Example 13−7 d
Page 395 and 396:
} glMatrixMode (GL_PROJECTION); glL
Page 397 and 398:
Chapter 14 Now That You Know Chapte
Page 399 and 400:
GL_STACK_OVERFLOW Command would cau
Page 401 and 402:
extension that is available only on
Page 403 and 404:
Each time through the loop, you cle
Page 405 and 406:
} } set_color(i,j); glVertex2i(x(i,
Page 407 and 408:
the bits of the appropriate color d
Page 409 and 410:
C, ..., I, where region I is outsid
Page 411 and 412:
Shadows Every possible projection o
Page 413 and 414:
you’ll need to clear the stencil
Page 415 and 416:
Figure 14−3 Dirichlet Domains If
Page 417 and 418:
Video⎯Even if your machine doesn
Page 419 and 420:
from specialized vertex arrays. Per
Page 421 and 422:
applied to the top matrix on the st
Page 423 and 424:
OpenGL State Variables The followin
Page 425 and 426:
GL_FOG_START Linear fog start fog 0
Page 427 and 428:
GL_TEXTURE_WRAP_x Texture wrap mode
Page 429 and 430:
GL_DOMAIN 1D domain endpoints ⎯
Page 431 and 432:
Appendix C OpenGL and Window System
Page 433 and 434:
glFinish(), glXWaitGL() doesn’t r
Page 435 and 436:
Use aglQueryVersion() to determine
Page 437 and 438:
AGLDrawable aglGetCurrentDrawable (
Page 439 and 440:
A shortcut for using OS/2 logical f
Page 441 and 442:
directly. CreateDIBitmap() creates
Page 443 and 444:
Appendix D Basics of GLUT: The Open
Page 445 and 446:
depending upon whether the mouse ha
Page 447 and 448:
Appendix E Calculating Normal Vecto
Page 449 and 450:
evaluated at a particular point (x,
Page 451 and 452:
Sometimes, you need to vary this me
Page 453 and 454:
transformations.) After transformat
Page 455 and 456:
As before, the inverses are obtaine
Page 457 and 458:
Appendix G Programming Tips This ap
Page 459 and 460:
computations. If your application r
Page 461 and 462:
Appendix H OpenGL Invariance OpenGL
Page 463 and 464:
Appendix I Color Plates This append
Page 465 and 466:
Plate 4 The scene drawn with flat
Page 467 and 468:
Plate 7 The scene drawn with one of
Page 469 and 470:
. Plate 10 Teapots drawn with jitte
Page 471 and 472:
Plate 14 Gray teapots drawn with di
Page 473 and 474:
. Plate 18 Lighted, green teapots d
Page 475 and 476:
Plate 21 An environment−mapped ob
Page 477 and 478:
Plate 23 A magnification of the pre
Page 479 and 480:
Plate 27 Sophisticated use of textu
Page 481 and 482:
Plate 31 Another scene from a diffe
Page 483 and 484:
itplane A rectangular array of bits
Page 485 and 486:
decal A method of calculating color
Page 487 and 488:
gamma correction A function applied
Page 489 and 490:
A source of illumination which has
Page 491 and 492:
A point, a line, a polygon, a bitma
Page 493 and 494:
The 4×4 matrix that transforms tex
Page 495:
Index
show all

OpenGL Programming Guide Second Edition - Niksula

Create successful ePaper yourself

Delete template?

Save as template?