xenocara/dist/Mesa/progs/xdemos/pbdemo.c
2006-11-25 18:56:37 +00:00

479 lines
11 KiB
C

/*
* This program demonstrates how to do "off-screen" rendering using
* the GLX pixel buffer extension.
*
* Written by Brian Paul for the "OpenGL and Window System Integration"
* course presented at SIGGRAPH '97. Updated on 5 October 2002.
*
* Usage:
* pbuffers width height imgfile
* Where:
* width is the width, in pixels, of the image to generate.
* height is the height, in pixels, of the image to generate.
* imgfile is the name of the PPM image file to write.
*
*
* This demo draws 3-D boxes with random orientation. A pbuffer with
* a depth (Z) buffer is prefered but if such a pbuffer can't be created
* we use a non-depth-buffered config.
*
* On machines such as the SGI Indigo you may have to reconfigure your
* display/X server to enable pbuffers. Look in the /usr/gfx/ucode/MGRAS/vof/
* directory for display configurationswith the _pbuf suffix. Use
* setmon -x <vof> to configure your X server and display for pbuffers.
*
* O2 systems seem to support pbuffers well.
*
* IR systems (at least 1RM systems) don't have single-buffered, RGBA,
* Z-buffered pbuffer configs. BUT, they DO have DOUBLE-buffered, RGBA,
* Z-buffered pbuffers. Note how we try four different fbconfig attribute
* lists below!
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include "pbutil.h"
/* Some ugly global vars */
static Display *gDpy = NULL;
static int gScreen = 0;
static FBCONFIG gFBconfig = 0;
static PBUFFER gPBuffer = 0;
static int gWidth, gHeight;
static GLXContext glCtx;
/*
* Create the pbuffer and return a GLXPbuffer handle.
*
* We loop over a list of fbconfigs trying to create
* a pixel buffer. We return the first pixel buffer which we successfully
* create.
*/
static PBUFFER
MakePbuffer( Display *dpy, int screen, int width, int height )
{
#define NUM_FB_CONFIGS 4
const char fbString[NUM_FB_CONFIGS][100] = {
"Single Buffered, depth buffer",
"Double Buffered, depth buffer",
"Single Buffered, no depth buffer",
"Double Buffered, no depth buffer"
};
int fbAttribs[NUM_FB_CONFIGS][100] = {
{
/* Single buffered, with depth buffer */
GLX_RENDER_TYPE, GLX_RGBA_BIT,
GLX_DRAWABLE_TYPE, GLX_PBUFFER_BIT,
GLX_RED_SIZE, 1,
GLX_GREEN_SIZE, 1,
GLX_BLUE_SIZE, 1,
GLX_DEPTH_SIZE, 1,
GLX_DOUBLEBUFFER, 0,
GLX_STENCIL_SIZE, 0,
None
},
{
/* Double buffered, with depth buffer */
GLX_RENDER_TYPE, GLX_RGBA_BIT,
GLX_DRAWABLE_TYPE, GLX_PBUFFER_BIT,
GLX_RED_SIZE, 1,
GLX_GREEN_SIZE, 1,
GLX_BLUE_SIZE, 1,
GLX_DEPTH_SIZE, 1,
GLX_DOUBLEBUFFER, 1,
GLX_STENCIL_SIZE, 0,
None
},
{
/* Single bufferd, without depth buffer */
GLX_RENDER_TYPE, GLX_RGBA_BIT,
GLX_DRAWABLE_TYPE, GLX_PBUFFER_BIT,
GLX_RED_SIZE, 1,
GLX_GREEN_SIZE, 1,
GLX_BLUE_SIZE, 1,
GLX_DEPTH_SIZE, 0,
GLX_DOUBLEBUFFER, 0,
GLX_STENCIL_SIZE, 0,
None
},
{
/* Double bufferd, without depth buffer */
GLX_RENDER_TYPE, GLX_RGBA_BIT,
GLX_DRAWABLE_TYPE, GLX_PBUFFER_BIT,
GLX_RED_SIZE, 1,
GLX_GREEN_SIZE, 1,
GLX_BLUE_SIZE, 1,
GLX_DEPTH_SIZE, 0,
GLX_DOUBLEBUFFER, 1,
GLX_STENCIL_SIZE, 0,
None
}
};
Bool largest = True;
Bool preserve = False;
FBCONFIG *fbConfigs;
PBUFFER pBuffer = None;
int nConfigs;
int i;
int attempt;
for (attempt=0; attempt<NUM_FB_CONFIGS; attempt++) {
/* Get list of possible frame buffer configurations */
fbConfigs = ChooseFBConfig(dpy, screen, fbAttribs[attempt], &nConfigs);
if (nConfigs==0 || !fbConfigs) {
printf("Error: glXChooseFBConfig failed\n");
XCloseDisplay(dpy);
return 0;
}
#if 0 /*DEBUG*/
for (i=0;i<nConfigs;i++) {
printf("Config %d\n", i);
PrintFBConfigInfo(dpy, screen, fbConfigs[i], 0);
}
#endif
/* Create the pbuffer using first fbConfig in the list that works. */
for (i=0;i<nConfigs;i++) {
pBuffer = CreatePbuffer(dpy, screen, fbConfigs[i], width, height, preserve, largest);
if (pBuffer) {
gFBconfig = fbConfigs[i];
gWidth = width;
gHeight = height;
break;
}
}
if (pBuffer!=None) {
break;
}
}
if (pBuffer) {
printf("Using: %s\n", fbString[attempt]);
}
XFree(fbConfigs);
return pBuffer;
#undef NUM_FB_CONFIGS
}
/*
* Do all the X / GLX setup stuff.
*/
static int
Setup(int width, int height)
{
int pbSupport;
XVisualInfo *visInfo;
/* Open the X display */
gDpy = XOpenDisplay(NULL);
if (!gDpy) {
printf("Error: couldn't open default X display.\n");
return 0;
}
/* Get default screen */
gScreen = DefaultScreen(gDpy);
/* Test that pbuffers are available */
pbSupport = QueryPbuffers(gDpy, gScreen);
if (pbSupport == 1) {
printf("Using GLX 1.3 Pbuffers\n");
}
else if (pbSupport == 2) {
printf("Using SGIX Pbuffers\n");
}
else {
printf("Error: pbuffers not available on this screen\n");
XCloseDisplay(gDpy);
return 0;
}
/* Create Pbuffer */
gPBuffer = MakePbuffer( gDpy, gScreen, width, height );
if (gPBuffer==None) {
printf("Error: couldn't create pbuffer\n");
XCloseDisplay(gDpy);
return 0;
}
/* Get corresponding XVisualInfo */
visInfo = GetVisualFromFBConfig(gDpy, gScreen, gFBconfig);
if (!visInfo) {
printf("Error: can't get XVisualInfo from FBconfig\n");
XCloseDisplay(gDpy);
return 0;
}
/* Create GLX context */
glCtx = glXCreateContext(gDpy, visInfo, NULL, True);
if (!glCtx) {
/* try indirect */
glCtx = glXCreateContext(gDpy, visInfo, NULL, False);
if (!glCtx) {
printf("Error: Couldn't create GLXContext\n");
XFree(visInfo);
XCloseDisplay(gDpy);
return 0;
}
else {
printf("Warning: using indirect GLXContext\n");
}
}
/* Bind context to pbuffer */
if (!glXMakeCurrent(gDpy, gPBuffer, glCtx)) {
printf("Error: glXMakeCurrent failed\n");
XFree(visInfo);
XCloseDisplay(gDpy);
return 0;
}
return 1; /* Success!! */
}
/* One-time GL setup */
static void
InitGL(void)
{
static GLfloat pos[4] = {0.0, 0.0, 10.0, 0.0};
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0, GL_POSITION, pos);
glEnable(GL_NORMALIZE);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glViewport(0, 0, gWidth, gHeight);
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -15.0 );
}
/* Return random float in [0,1] */
static float
Random(void)
{
int i = rand();
return (float) (i % 1000) / 1000.0;
}
static void
RandomColor(void)
{
GLfloat c[4];
c[0] = Random();
c[1] = Random();
c[2] = Random();
c[3] = 1.0;
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, c);
}
/* This function borrowed from Mark Kilgard's GLUT */
static void
drawBox(GLfloat x0, GLfloat x1, GLfloat y0, GLfloat y1,
GLfloat z0, GLfloat z1, GLenum type)
{
static GLfloat n[6][3] =
{
{-1.0, 0.0, 0.0},
{0.0, 1.0, 0.0},
{1.0, 0.0, 0.0},
{0.0, -1.0, 0.0},
{0.0, 0.0, 1.0},
{0.0, 0.0, -1.0}
};
static GLint faces[6][4] =
{
{0, 1, 2, 3},
{3, 2, 6, 7},
{7, 6, 5, 4},
{4, 5, 1, 0},
{5, 6, 2, 1},
{7, 4, 0, 3}
};
GLfloat v[8][3], tmp;
GLint i;
if (x0 > x1) {
tmp = x0;
x0 = x1;
x1 = tmp;
}
if (y0 > y1) {
tmp = y0;
y0 = y1;
y1 = tmp;
}
if (z0 > z1) {
tmp = z0;
z0 = z1;
z1 = tmp;
}
v[0][0] = v[1][0] = v[2][0] = v[3][0] = x0;
v[4][0] = v[5][0] = v[6][0] = v[7][0] = x1;
v[0][1] = v[1][1] = v[4][1] = v[5][1] = y0;
v[2][1] = v[3][1] = v[6][1] = v[7][1] = y1;
v[0][2] = v[3][2] = v[4][2] = v[7][2] = z0;
v[1][2] = v[2][2] = v[5][2] = v[6][2] = z1;
for (i = 0; i < 6; i++) {
glBegin(type);
glNormal3fv(&n[i][0]);
glVertex3fv(&v[faces[i][0]][0]);
glVertex3fv(&v[faces[i][1]][0]);
glVertex3fv(&v[faces[i][2]][0]);
glVertex3fv(&v[faces[i][3]][0]);
glEnd();
}
}
/* Render a scene */
static void
Render(void)
{
int NumBoxes = 100;
int i;
glClearColor(0.2, 0.2, 0.9, 0.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
for (i=0;i<NumBoxes;i++) {
float tx = -2.0 + 4.0 * Random();
float ty = -2.0 + 4.0 * Random();
float tz = 4.0 - 16.0 * Random();
float sx = 0.1 + Random() * 0.4;
float sy = 0.1 + Random() * 0.4;
float sz = 0.1 + Random() * 0.4;
float rx = Random();
float ry = Random();
float rz = Random();
float ra = Random() * 360.0;
glPushMatrix();
glTranslatef(tx, ty, tz);
glRotatef(ra, rx, ry, rz);
glScalef(sx, sy, sz);
RandomColor();
drawBox(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0, GL_POLYGON);
glPopMatrix();
}
glFinish();
}
static void
WriteFile(const char *filename)
{
FILE *f;
GLubyte *image;
int i;
image = malloc(gWidth * gHeight * 3 * sizeof(GLubyte));
if (!image) {
printf("Error: couldn't allocate image buffer\n");
return;
}
glPixelStorei(GL_PACK_ALIGNMENT, 1);
glReadPixels(0, 0, gWidth, gHeight, GL_RGB, GL_UNSIGNED_BYTE, image);
f = fopen(filename, "w");
if (!f) {
printf("Couldn't open image file: %s\n", filename);
return;
}
fprintf(f,"P6\n");
fprintf(f,"# ppm-file created by %s\n", "trdemo2");
fprintf(f,"%i %i\n", gWidth, gHeight);
fprintf(f,"255\n");
fclose(f);
f = fopen(filename, "ab"); /* now append binary data */
if (!f) {
printf("Couldn't append to image file: %s\n", filename);
return;
}
for (i=0;i<gHeight;i++) {
GLubyte *rowPtr;
/* Remember, OpenGL images are bottom to top. Have to reverse. */
rowPtr = image + (gHeight-1-i) * gWidth*3;
fwrite(rowPtr, 1, gWidth*3, f);
}
fclose(f);
free(image);
printf("Wrote %d by %d image file: %s\n", gWidth, gHeight, filename);
}
/*
* Print message describing command line parameters.
*/
static void
Usage(const char *appName)
{
printf("Usage:\n");
printf(" %s width height imgfile\n", appName);
printf("Where imgfile is a ppm file\n");
}
int
main(int argc, char *argv[])
{
if (argc!=4) {
Usage(argv[0]);
}
else {
int width = atoi(argv[1]);
int height = atoi(argv[2]);
char *fileName = argv[3];
if (width<=0) {
printf("Error: width parameter must be at least 1.\n");
return 1;
}
if (height<=0) {
printf("Error: height parameter must be at least 1.\n");
return 1;
}
if (!Setup(width, height)) {
return 1;
}
InitGL();
Render();
WriteFile(fileName);
DestroyPbuffer(gDpy, gScreen, gPBuffer);
}
return 0;
}