curt
25b743bdec
being careful to manually call getState()->apply() before the glPushAttrib() so that the ssg state handling mechanism doesn't get derailed accidentally.
400 lines
11 KiB
C++
400 lines
11 KiB
C++
// oursun.hxx -- model earth's sun
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//
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// Written by Durk Talsma. Originally started October 1997, for distribution
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// with the FlightGear project. Version 2 was written in August and
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// September 1998. This code is based upon algorithms and data kindly
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// provided by Mr. Paul Schlyter. (pausch@saaf.se).
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//
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// Separated out rendering pieces and converted to ssg by Curt Olson,
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// March 2000
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Library General Public License for more details.
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//
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// You should have received a copy of the GNU Library General Public
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// License along with this library; if not, write to the
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// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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// Boston, MA 02111-1307, USA.
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//
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// $Id$
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdio.h>
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#include <iostream>
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#include <plib/sg.h>
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#include <plib/ssg.h>
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#include "sphere.hxx"
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#include "oursun.hxx"
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// Set up sun rendering call backs
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static int sgSunOrbPreDraw( ssgEntity *e ) {
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/* cout << endl << "Sun orb pre draw" << endl << "----------------"
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<< endl << endl; */
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ssgLeaf *f = (ssgLeaf *)e;
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if ( f -> hasState () ) f->getState()->apply() ;
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glPushAttrib( GL_DEPTH_BUFFER_BIT | GL_FOG_BIT );
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// cout << "push error = " << glGetError() << endl;
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glDisable( GL_DEPTH_TEST );
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glDisable( GL_FOG );
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return true;
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}
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static int sgSunOrbPostDraw( ssgEntity *e ) {
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/* cout << endl << "Sun orb post draw" << endl << "----------------"
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<< endl << endl; */
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glPopAttrib();
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// cout << "pop error = " << glGetError() << endl;
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// glEnable( GL_DEPTH_TEST );
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// glEnable( GL_FOG );
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return true;
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}
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static int sgSunHaloPreDraw( ssgEntity *e ) {
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/* cout << endl << "Sun halo pre draw" << endl << "----------------"
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<< endl << endl; */
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ssgLeaf *f = (ssgLeaf *)e;
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if ( f -> hasState () ) f->getState()->apply() ;
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glPushAttrib( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_FOG_BIT );
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// cout << "push error = " << glGetError() << endl;
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glDisable( GL_DEPTH_TEST );
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glDisable( GL_FOG );
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glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
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return true;
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}
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static int sgSunHaloPostDraw( ssgEntity *e ) {
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/* cout << endl << "Sun halo post draw" << endl << "----------------"
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<< endl << endl; */
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glPopAttrib();
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// cout << "pop error = " << glGetError() << endl;
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// glEnable( GL_DEPTH_TEST );
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// glEnable( GL_FOG );
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return true;
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}
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// Constructor
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SGSun::SGSun( void ) {
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}
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// Destructor
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SGSun::~SGSun( void ) {
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}
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#if 0
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static GLuint makeHalo( GLubyte *sun_texbuf, int width ) {
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int texSize;
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GLuint texid;
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GLubyte *p;
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int i,j;
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double radius;
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// create a texture id
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#ifdef GL_VERSION_1_1
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glGenTextures(1, &texid);
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glBindTexture(GL_TEXTURE_2D, texid);
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#elif GL_EXT_texture_object
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glGenTexturesEXT(1, &texid);
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glBindTextureEXT(GL_TEXTURE_2D, texid);
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#else
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# error port me
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#endif
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glPixelStorei( GL_UNPACK_ALIGNMENT, 4 );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
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glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE ) ;
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// create the actual texture contents
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texSize = width * width;
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if ( !sun_texbuf ) {
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cout << "ouch ..." << endl;
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exit(-1); // Ugly!
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}
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p = sun_texbuf;
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radius = (double)(width / 2);
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GLubyte value;
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double x, y, d;
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for ( i = 0; i < width; i++ ) {
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for ( j = 0; j < width; j++ ) {
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x = fabs((double)(i - (width / 2)));
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y = fabs((double)(j - (width / 2)));
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d = sqrt((x * x) + (y * y));
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if (d < radius) {
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// t is 1.0 at center, 0.0 at edge
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double t = 1.0 - (d / radius);
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// inverse square looks nice
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value = (int)((double) 0xff * (t*t));
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} else {
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value = 0x00;
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}
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*p = value;
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*(p+1) = value;
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*(p+2) = value;
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// *(p+3) = value;
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p += 3;
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}
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}
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/* glTexImage2D( GL_TEXTURE_2D,
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0,
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GL_RGBA,
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width, width,
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0,
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GL_RGBA, GL_UNSIGNED_BYTE,
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sun_texbuf ); */
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return texid;
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}
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#define RGB 3 // 3 bytes of color info per pixel
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#define RGBA 4 // 4 bytes of color+alpha info
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void my_glWritePPMFile(const char *filename, GLubyte *buffer, int win_width, int win_height, int mode)
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{
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int i, j, k, q;
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unsigned char *ibuffer;
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FILE *fp;
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int pixelSize = mode==GL_RGBA?4:3;
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ibuffer = (unsigned char *) malloc(win_width*win_height*RGB);
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fp = fopen(filename, "wb");
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fprintf(fp, "P6\n# CREATOR: glReadPixel()\n%d %d\n%d\n",
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win_width, win_height, UCHAR_MAX);
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q = 0;
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for (i = 0; i < win_height; i++) {
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for (j = 0; j < win_width; j++) {
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for (k = 0; k < RGB; k++) {
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ibuffer[q++] = (unsigned char)
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*(buffer + (pixelSize*((win_height-1-i)*win_width+j)+k));
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}
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}
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}
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// *(buffer + (pixelSize*((win_height-1-i)*win_width+j)+k));
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fwrite(ibuffer, sizeof(unsigned char), RGB*win_width*win_height, fp);
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fclose(fp);
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free(ibuffer);
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printf("wrote file (%d x %d pixels, %d bytes)\n",
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win_width, win_height, RGB*win_width*win_height);
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}
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#endif
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// initialize the sun object and connect it into our scene graph root
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ssgBranch * SGSun::build( FGPath path, double sun_size ) {
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// set up the orb state
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orb_state = new ssgSimpleState();
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orb_state->setShadeModel( GL_SMOOTH );
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orb_state->disable( GL_LIGHTING );
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// orb_state->enable( GL_LIGHTING );
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orb_state->disable( GL_CULL_FACE );
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orb_state->disable( GL_TEXTURE_2D );
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orb_state->enable( GL_COLOR_MATERIAL );
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orb_state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
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orb_state->setMaterial( GL_EMISSION, 0, 0, 0, 1 );
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orb_state->setMaterial( GL_SPECULAR, 0, 0, 0, 1 );
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orb_state->disable( GL_BLEND );
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orb_state->disable( GL_ALPHA_TEST );
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cl = new ssgColourArray( 1 );
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sgVec4 color;
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sgSetVec4( color, 1.0, 1.0, 1.0, 1.0 );
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cl->add( color );
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ssgBranch *orb = ssgMakeSphere( orb_state, cl, sun_size, 10, 10,
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sgSunOrbPreDraw, sgSunOrbPostDraw );
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// force a repaint of the sun colors with arbitrary defaults
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repaint( 0.0 );
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// build the halo
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// sun_texbuf = new GLubyte[64*64*3];
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// sun_texid = makeHalo( sun_texbuf, 64 );
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// my_glWritePPMFile("sunhalo.ppm", sun_texbuf, 64, 64, RGB);
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// set up the halo state
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path.append( "halo.rgba" );
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halo_state = new ssgSimpleState();
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halo_state->setTexture( (char *)path.c_str() );
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halo_state->enable( GL_TEXTURE_2D );
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halo_state->disable( GL_LIGHTING );
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// halo_state->enable( GL_LIGHTING );
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halo_state->setShadeModel( GL_SMOOTH );
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halo_state->disable( GL_CULL_FACE );
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halo_state->enable( GL_COLOR_MATERIAL );
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halo_state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
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halo_state->setMaterial( GL_EMISSION, 0, 0, 0, 1 );
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halo_state->setMaterial( GL_SPECULAR, 0, 0, 0, 1 );
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halo_state->enable( GL_ALPHA_TEST );
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halo_state->setAlphaClamp(0.01);
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halo_state->enable ( GL_BLEND ) ;
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// Build ssg structure
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double size = sun_size * 10.0;
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sgVec3 v3;
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halo_vl = new ssgVertexArray;
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sgSetVec3( v3, -size, 0.0, -size );
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halo_vl->add( v3 );
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sgSetVec3( v3, size, 0.0, -size );
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halo_vl->add( v3 );
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sgSetVec3( v3, -size, 0.0, size );
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halo_vl->add( v3 );
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sgSetVec3( v3, size, 0.0, size );
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halo_vl->add( v3 );
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sgVec2 v2;
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halo_tl = new ssgTexCoordArray;
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sgSetVec2( v2, 0.0f, 0.0f );
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halo_tl->add( v2 );
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sgSetVec2( v2, 1.0, 0.0 );
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halo_tl->add( v2 );
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sgSetVec2( v2, 0.0, 1.0 );
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halo_tl->add( v2 );
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sgSetVec2( v2, 1.0, 1.0 );
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halo_tl->add( v2 );
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ssgLeaf *halo =
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new ssgVtxTable ( GL_TRIANGLE_STRIP, halo_vl, NULL, halo_tl, cl );
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halo->setState( halo_state );
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// build the ssg scene graph sub tree for the sky and connected
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// into the provide scene graph branch
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sun_transform = new ssgTransform;
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halo->setCallback( SSG_CALLBACK_PREDRAW, sgSunHaloPreDraw );
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halo->setCallback( SSG_CALLBACK_POSTDRAW, sgSunHaloPostDraw );
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sun_transform->addKid( halo );
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sun_transform->addKid( orb );
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return sun_transform;
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}
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// repaint the sun colors based on current value of sun_angle in
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// degrees relative to verticle
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// 0 degrees = high noon
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// 90 degrees = sun rise/set
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// 180 degrees = darkest midnight
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bool SGSun::repaint( double sun_angle ) {
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if ( sun_angle * SGD_RADIANS_TO_DEGREES < 100 ) {
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// else sun is well below horizon (so no point in repainting it)
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// x_10 = sun_angle^10
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double x_10 = sun_angle * sun_angle * sun_angle * sun_angle * sun_angle
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* sun_angle * sun_angle * sun_angle * sun_angle * sun_angle;
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float ambient = (float)(0.4 * pow (1.1, - x_10 / 30.0));
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if (ambient < 0.3) { ambient = 0.3; }
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if (ambient > 1.0) { ambient = 1.0; }
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sgVec4 color;
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sgSetVec4( color,
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(ambient * 6.0) - 1.0, // minimum value = 0.8
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(ambient * 11.0) - 3.0, // minimum value = 0.3
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(ambient * 12.0) - 3.6, // minimum value = 0.0
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1.0 );
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// temp test, forces the color to always be white
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// sgSetVec4( color, 1.0, 1.0, 1.0, 1.0 );
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if (color[0] > 1.0) color[0] = 1.0;
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if (color[1] > 1.0) color[1] = 1.0;
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if (color[2] > 1.0) color[2] = 1.0;
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// cout << "color = " << color[0] << " " << color[1] << " "
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// << color[2] << endl;
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float *ptr;
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ptr = cl->get( 0 );
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sgCopyVec4( ptr, color );
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}
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return true;
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}
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// reposition the sun at the specified right ascension and
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// declination, offset by our current position (p) so that it appears
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// fixed at a great distance from the viewer. Also add in an optional
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// rotation (i.e. for the current time of day.)
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bool SGSun::reposition( sgVec3 p, double angle,
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double rightAscension, double declination,
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double sun_dist )
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{
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sgMat4 T1, T2, GST, RA, DEC;
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sgVec3 axis;
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sgVec3 v;
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sgMakeTransMat4( T1, p );
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sgSetVec3( axis, 0.0, 0.0, -1.0 );
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sgMakeRotMat4( GST, angle, axis );
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// xglRotatef( ((SGD_RADIANS_TO_DEGREES * rightAscension)- 90.0),
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// 0.0, 0.0, 1.0);
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sgSetVec3( axis, 0.0, 0.0, 1.0 );
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sgMakeRotMat4( RA, (rightAscension * SGD_RADIANS_TO_DEGREES) - 90.0, axis );
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// xglRotatef((SGD_RADIANS_TO_DEGREES * declination), 1.0, 0.0, 0.0);
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sgSetVec3( axis, 1.0, 0.0, 0.0 );
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sgMakeRotMat4( DEC, declination * SGD_RADIANS_TO_DEGREES, axis );
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// xglTranslatef(0,sun_dist);
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sgSetVec3( v, 0.0, sun_dist, 0.0 );
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sgMakeTransMat4( T2, v );
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sgMat4 TRANSFORM;
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sgCopyMat4( TRANSFORM, T1 );
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sgPreMultMat4( TRANSFORM, GST );
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sgPreMultMat4( TRANSFORM, RA );
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sgPreMultMat4( TRANSFORM, DEC );
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sgPreMultMat4( TRANSFORM, T2 );
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sgCoord skypos;
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sgSetCoord( &skypos, TRANSFORM );
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sun_transform->setTransform( &skypos );
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return true;
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}
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