grtrackmap.cpp

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/***************************************************************************
 
    file                 : grtrackmap.cpp
    created              : Fri Aug 29 00:58:00 CEST 2003
    copyright            : (C) 2003 by Bernhard Wymann
    email                : berniw@bluewin.ch
    version              : $Id$
 
 ***************************************************************************/
 
/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
/*
    This class displays an overview map of the track, such that you can see the
    upcoming track layout. Your car is displayed as a dot.
    To get reasonable efficiency, the track is first rendered into a texture. During the
    game just the texture needs to be redrawn.
*/
 
#include "grtrackmap.h"
#include <tgfclient.h>
 
// The resolution in [m] to analyse turns.
const float cGrTrackMap::RESOLUTION = 5.0;
 
// Minimum and Maximum line width in pixels to draw the track.
const float cGrTrackMap::MINLINEWIDTH = 5.0;
const float cGrTrackMap::MAXLINEWIDTH = 20.0;
 
// Some data needs just one initalization, after first initialization this is set to true.
bool cGrTrackMap::isinitalized = false;
 
// Track overview texture object.
GLuint cGrTrackMap::mapTexture;
 
// The car "dot" display list.
GLuint cGrTrackMap::cardot;
 
// Track bounding box properties, lower left, upper right corner, width and height.
float cGrTrackMap::track_min_x;
float cGrTrackMap::track_max_x;
float cGrTrackMap::track_min_y;
float cGrTrackMap::track_max_y;
float cGrTrackMap::track_width;
float cGrTrackMap::track_height;
 
// The ratio of width and height to MAX(width, height)
float cGrTrackMap::track_x_ratio;
float cGrTrackMap::track_y_ratio;
 
// Position and size of the map (relative to top left).
int cGrTrackMap::map_x;
int cGrTrackMap::map_y;
int cGrTrackMap::map_size;
 
// Scaling factor from meters to texels.
float cGrTrackMap::ratio;
 
// Color of the cars "dots".
GLfloat cGrTrackMap::currentCarColor[4];
GLfloat cGrTrackMap::aheadCarColor[4];
GLfloat cGrTrackMap::behindCarColor[4];
 
 
// The constructor creates a texture of the track data, such that the track
// layout can be displayed efficiently. Additional data gets initialized.
cGrTrackMap::cGrTrackMap()
{
    // Hardcoded initial view mode, available per instance.
    viewmode = TRACK_MAP_NORMAL_WITH_OPPONENTS;
 
    // For all views we need the same track texture, so create it just once.
    if (isinitalized) {
        return;
    } else {
        // Initialize colors for the various car "dots".
        initColors();
 
        tTrack *track = grTrack;
        tTrackSeg* first = track->seg;
        tTrackSeg* seg = first;
 
        // Search the maximum/minimum x/y values of the track (axis aligned bounding box),
        // to compute later the texture parameters and to be able to place the cars (dots)
        // correct. The impementation is inefficient, but it's just executed one time per
        // race, so it doesn't matter.
        track_min_x = FLT_MAX;
        track_max_x = -FLT_MAX;
        track_min_y = FLT_MAX;
        track_max_y = -FLT_MAX;
 
        do {
            // We analyse the straight and turns different, because (read on)
            if (seg->type == TR_STR) {
                // Straights are trivial, because the corners are sufficient to create a
                // bounding box.
                // TODO: If CCW/CW is known, you just need to check one side (the outside).
                // TODO: More effiecient checking.
                checkAndSetMinimum(track_min_x, seg->vertex[TR_SL].x);
                checkAndSetMinimum(track_min_x, seg->vertex[TR_SR].x);
                checkAndSetMinimum(track_min_y, seg->vertex[TR_SL].y);
                checkAndSetMinimum(track_min_y, seg->vertex[TR_SR].y);
 
                checkAndSetMaximum(track_max_x, seg->vertex[TR_SL].x);
                checkAndSetMaximum(track_max_x, seg->vertex[TR_SR].x);
                checkAndSetMaximum(track_max_y, seg->vertex[TR_SL].y);
                checkAndSetMaximum(track_max_y, seg->vertex[TR_SR].y);
            } else {
                // Turns are not that easy, think of a definition of a circle or an arc. If you
                // just consider the corners the bounding box might be any order too small
                // or too big.
                // To avoid that we create intermediate steps, such that we get a defined
                // accuracy (e.g. 5 meters).
                float curseglen = 0.0;
                float dphi = RESOLUTION / seg->radius;
                double xc = seg->center.x;
                double yc = seg->center.y;
                dphi = (seg->type == TR_LFT) ? dphi : -dphi;
                float phi = 0.0;
 
                while (curseglen < seg->length) {
                    float cs = cos(phi), ss = sin(phi);
                    // TODO: If CCW/CW is known, you just need to check one side (the outside).
                    float lx, ly, rx, ry;
                    lx = seg->vertex[TR_SL].x * cs - seg->vertex[TR_SL].y * ss - xc * cs + yc * ss + xc;
                    ly = seg->vertex[TR_SL].x * ss + seg->vertex[TR_SL].y * cs - xc * ss - yc * cs + yc;
 
                    rx = seg->vertex[TR_SR].x * cs - seg->vertex[TR_SR].y * ss - xc * cs + yc * ss + xc;
                    ry = seg->vertex[TR_SR].x * ss + seg->vertex[TR_SR].y * cs - xc * ss - yc * cs + yc;
 
                    // TODO: More effiecient checking.
                    checkAndSetMinimum(track_min_x, lx);
                    checkAndSetMinimum(track_min_x, rx);
                    checkAndSetMinimum(track_min_y, ly);
                    checkAndSetMinimum(track_min_y, ry);
 
                    checkAndSetMaximum(track_max_x, lx);
                    checkAndSetMaximum(track_max_x, rx);
                    checkAndSetMaximum(track_max_y, ly);
                    checkAndSetMaximum(track_max_y, ry);
 
                    curseglen += RESOLUTION;
                    phi += dphi;
                }
            }
            seg = seg->next;
        } while (seg != first);
 
        // Compute the maximum possible texture size possible to create the track texture.
        // TODO: use pbuffer if available or subdivide and render/readback in multiple passes.
        int texturesize = 1;
        int maxtexturesize = MIN(grWinw, grWinh);
        while (texturesize <= maxtexturesize) {
            texturesize <<= 1;
        }
        texturesize >>= 1;
 
        // Get maximum OpenGL texture size and reduce texturesize if necessary.
        int maxOpenGLtexturesize;
        glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxOpenGLtexturesize);
        if (texturesize > maxOpenGLtexturesize) {
            texturesize = maxOpenGLtexturesize;
        }
 
        // Compute an estimate of the overall width and height of the track in [m].
        track_width = track_max_x - track_min_x;
        track_height = track_max_y - track_min_y;
 
        // Compute the final line width to draw the track.
        float linewidth = MIN(MAXLINEWIDTH, MINLINEWIDTH*4000.0/MAX(track_width, track_height));
        linewidth = linewidth*(texturesize/512.0);
 
        // Compute a first estimate of the pixel to distance ratio.
        ratio = texturesize/MAX(track_width, track_height);
 
        // Compute final minimum/maximum values.
        track_max_x = track_max_x + RESOLUTION + linewidth/ratio;
        track_max_y = track_max_y + RESOLUTION + linewidth/ratio;
        track_min_x = track_min_x - RESOLUTION - linewidth/ratio;
        track_min_y = track_min_y - RESOLUTION - linewidth/ratio;
 
        // Compute final ratio, width and height.
        track_width = track_max_x - track_min_x;
        track_height = track_max_y - track_min_y;
        ratio = texturesize/MAX(track_width, track_height);
 
        // Compute the ratios
        if (track_width >= track_height) {
            track_x_ratio = 1.0;
            track_y_ratio = track_height/track_width;
        } else {
            track_y_ratio = 1.0;
            track_x_ratio = track_width/track_height;
        }
 
        isinitalized = true;
 
        // Now we are ready to render the track into the framebuffer (backbuffer).
        // Clear the framebuffer (backbuffer), make it "transparent" (alpha = 0.0).
        glFinish();
        glClearColor(0.0, 0.0, 0.0, 0.0);
        glClear(GL_COLOR_BUFFER_BIT);
 
        // Set transformations and projection such that one pixel is one unit.
        glViewport (0, 0, grWinw, grWinh);
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glLoadIdentity();
 
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluOrtho2D(0.0, grWinw, 0.0, grWinh);
        glMatrixMode(GL_MODELVIEW);
 
        // Now draw the track as quad strip. The reason for that is that drawing with
        // glEnable(GL_LINE_SMOOTH) and glHint(GL_LINE_SMOOTH_HINT, GL_NICEST) caused problems
        // with the alpha channel.
        float halflinewidth = linewidth/2.0;
        bool firstvert = true;
        float xf1, yf1 , xf2, yf2;
        xf1 = yf1 = xf2 = yf2 = 0.0;
        glBegin(GL_QUAD_STRIP);
        seg = first;
        do {
            if (seg->type == TR_STR) {
                // Draw a straight.
                // Compute global coordinate on track middle.
                float xm = (seg->vertex[TR_SL].x + seg->vertex[TR_SR].x) / 2.0;
                float ym = (seg->vertex[TR_SL].y + seg->vertex[TR_SR].y) / 2.0;
                xm = (xm - track_min_x)*ratio;
                ym = (ym - track_min_y)*ratio;
 
                // Compute normal to the track middle.
                float xn = seg->vertex[TR_SL].x - seg->vertex[TR_SR].x;
                float yn = seg->vertex[TR_SL].y - seg->vertex[TR_SR].y;
                float length = sqrt(xn*xn+yn*yn);
                xn /= length;
                yn /= length;
 
                // Compute the new points.
                float x1 = (xm - xn*halflinewidth);
                float y1 = (ym - yn*halflinewidth);
                float x2 = (xm + xn*halflinewidth);
                float y2 = (ym + yn*halflinewidth);
 
                if (firstvert) {
                    firstvert = false;
                    xf1 = x1;
                    yf1 = y1;
                    xf2 = x2;
                    yf2 = y2;
                }
                glVertex2f(x1, y1);
                glVertex2f(x2, y2);
            } else {
                // To draw the turns correct we subdivide them again, like above.
                float curseglen = 0.0;
                float dphi = RESOLUTION / seg->radius;
                double xc = seg->center.x;
                double yc = seg->center.y;
                dphi = (seg->type == TR_LFT) ? dphi : -dphi;
                float mx = (seg->vertex[TR_SL].x + seg->vertex[TR_SR].x) / 2.0;
                float my = (seg->vertex[TR_SL].y + seg->vertex[TR_SR].y) / 2.0;
                float phi = 0.0;
 
                while (curseglen < seg->length) {
                    float cs = cos(phi), ss = sin(phi);
                    float x = mx * cs - my * ss - xc * cs + yc * ss + xc;
                    float y = mx * ss + my * cs - xc * ss - yc * cs + yc;
 
                    float xn = x - xc;
                    float yn = y - yc;
                    float length = sqrt(xn*xn+yn*yn);
                    xn /= length;
                    yn /= length;
 
                    x = (x - track_min_x)*ratio;
                    y = (y - track_min_y)*ratio;
 
                    float x1 = (x + xn*halflinewidth);
                    float y1 = (y + yn*halflinewidth);
                    float x2 = (x - xn*halflinewidth);
                    float y2 = (y - yn*halflinewidth);
 
                    if (seg->type == TR_LFT) {
                        glVertex2f(x1, y1);
                        glVertex2f(x2, y2);
                        if (firstvert) {
                            firstvert = false;
                            xf1 = x1;
                            yf1 = y1;
                            xf2 = x2;
                            yf2 = y2;
                        }
                    } else {
                        glVertex2f(x2, y2);
                        glVertex2f(x1, y1);
                        if (firstvert) {
                            firstvert = false;
                            xf1 = x2;
                            yf1 = y2;
                            xf2 = x1;
                            yf2 = y1;
                        }
                    }
 
                    curseglen += RESOLUTION;
                    phi += dphi;
                }
            }
            seg = seg->next;
        } while (seg != first);
 
        if (!firstvert) {
            glVertex2f(xf1, yf1);
            glVertex2f(xf2, yf2);
        }
        glEnd();
 
        // Read track picture into memory to be able to generate mipmaps. I read back an RGBA
        // image because I don't know yet what people want to add to the map, so RGBA is most
        // flexible to add things like start line, elevation coloring etc.
        // Do not use GL_ALPHA or GL_LUMINANCE to save memory, somehow this leads to a
        // performance penalty (at least on NVidia cards).
        GLuint *trackImage = (GLuint*) malloc(texturesize*texturesize*sizeof(GLuint));
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glPixelStorei(GL_PACK_ALIGNMENT, 1);
        glReadBuffer(GL_BACK);
        glReadPixels(0, 0, texturesize, texturesize, GL_RGBA, GL_BYTE, trackImage);
 
        // Check if the color buffer has alpha, if not fix the texture. Black gets
        // replaced by transparent black, so don't draw black in the texture, you
        // won't see anything.
        if (glutGet(GLUT_WINDOW_ALPHA_SIZE) == 0) {
            // There is no alpha, so we fix it manually. Because we added a little border
            // around the track map the first pixel should always contain the
            // clearcolor.
            GLuint clearcolor = trackImage[0];
            int i;
            for (i = 0; i < texturesize*texturesize; i++) {
                if (trackImage[i] == clearcolor) {
                    // Assumption: transparent black is 0, portable?
                    trackImage[i] = 0;
                }
            }
        }
 
        // Finally copy the created image of the track from the framebuffer into the texture.
        glGenTextures (1, &mapTexture);
        glBindTexture(GL_TEXTURE_2D, mapTexture);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 
 
        // If GL_ARB_texture_compression is available at runtime, (try to) compress the
        // texture. This is done with the specification of the internal format to
        // GL_COMPRESSED_RGBA_ARB.
        if (isCompressARBAvailable()) {
            // This texture contains mostly the clear color value and should therefore
            // compress well even with high quality.
            glHint(GL_TEXTURE_COMPRESSION_HINT_ARB, GL_NICEST);
            gluBuild2DMipmaps(GL_TEXTURE_2D, GL_COMPRESSED_RGBA_ARB, texturesize, texturesize, GL_RGBA, GL_BYTE, trackImage);
            // The following commented code is just for testing purposes.
            /*int compressed;
            glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED_ARB, &compressed);
            if (compressed == GL_TRUE) {
                int csize;
                printf("compression succesful!\n");
                glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED_IMAGE_SIZE_ARB, &csize);
                printf("compression ratio: %d to %d\n", csize, texturesize*texturesize*sizeof(GLuint));
            }*/
        } else {
            // GL_ARB_texture_compression not available at runtime, fallback.
            gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGBA, texturesize, texturesize, GL_RGBA, GL_BYTE, trackImage);
        }
 
        // Free the memory of the initial texture.
        free(trackImage);
 
        // Init the position and size of the map in the window.
        map_x = -10;
        map_y = -40;
        map_size = 170;
 
        // Restore some state.
        glPopMatrix();
 
        // Compile the car "dot" display list.
        cardot = glGenLists(1);
        if (cardot != 0) {
            glNewList(cardot, GL_COMPILE);
            glBegin(GL_TRIANGLE_FAN);
            // The center.
            glVertex2f(0.0, 0.0);
            // The border.
            int i;
            const int borderpoints = 8;
            halflinewidth = halflinewidth*float(map_size)/float(texturesize);
            for (i = 0; i < borderpoints + 1; i++) {
                float phi = 2.0*PI*float(i)/float(borderpoints);
                glVertex2f(halflinewidth*cos(phi), halflinewidth*sin(phi));
            }
            glEnd();
            glEndList();
        }
 
        // Clear the screen, that in case of a delay the track is not visible.
        glClear(GL_COLOR_BUFFER_BIT);
    }
}
 
 
// Release the texture and data.
cGrTrackMap::~cGrTrackMap()
{
    // We have just one track texture object, so delete it just once.
    if (isinitalized) {
        glDeleteTextures(1, &mapTexture);
        isinitalized = false;
        if (cardot != 0) {
            glDeleteLists(cardot, 1);
        }
    }
}
 
 
// Walk trough the different available display modes
void cGrTrackMap::selectTrackMap()
{
    viewmode <<= 1;
    if (viewmode > TRACK_MAP_MASK) {
        viewmode = TRACK_MAP_NONE;
    }
}
 
 
// Draw the track map according to the display mode
void cGrTrackMap::display(
    tCarElt *currentCar,
    tSituation *situation,
    int Winx,
    int Winy,
    int Winw,
    int Winh
)
{
    if (viewmode == TRACK_MAP_NONE) {
        return;
    }
 
    // Compute track map position.
    int x = Winx + Winw + map_x - (int) (map_size*track_x_ratio);
    int y = Winy + Winh + map_y - (int) (map_size*track_y_ratio);
 
    // Setup and display track map.
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_TEXTURE_2D);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
    glBindTexture(GL_TEXTURE_2D, mapTexture);
 
    // Draw track.
    if (viewmode & (TRACK_MAP_NORMAL | TRACK_MAP_NORMAL_WITH_OPPONENTS)) {
        drawTrackNormal(x, y);
    } else if (viewmode & (TRACK_MAP_PAN | TRACK_MAP_PAN_WITH_OPPONENTS)) {
        drawTrackPanning(Winx, Winy, Winw, Winh, currentCar, situation);
    } else if (viewmode & (TRACK_MAP_PAN_ALIGNED | TRACK_MAP_PAN_ALIGNED_WITH_OPPONENTS)) {
        drawTrackPanningAligned(Winx, Winy, Winw, Winh, currentCar, situation);
    }
 
    // Draw cars in normal map mode.
    if (viewmode & TRACK_MAP_NORMAL_WITH_OPPONENTS) {
        drawCars(currentCar, situation, x, y);
    }
    if (viewmode & (TRACK_MAP_NORMAL | TRACK_MAP_NORMAL_WITH_OPPONENTS)) {
        drawCar(currentCar, currentCarColor, x, y);
    }
 
}
 
 
// Draw the track full visible and static.
void cGrTrackMap::drawTrackNormal(int x, int y)
{
    glBegin(GL_QUADS);
    glTexCoord2f(0.0, 0.0); glVertex2f(x, y);
    glTexCoord2f(1.0, 0.0); glVertex2f(x + map_size, y);
    glTexCoord2f(1.0, 1.0); glVertex2f(x + map_size, y + map_size);
    glTexCoord2f(0.0, 1.0); glVertex2f(x, y + map_size);
    glEnd();
}
 
 
// Draw the track in the panning mode.
void cGrTrackMap::drawTrackPanning(
    int Winx,
    int Winy,
    int Winw,
    int Winh,
    tCarElt *currentCar,
    tSituation *s
)
{
    float x1, y1, x2, y2;
    float tracksize = MAX(track_width, track_height);
    float radius = MIN(500.0, tracksize/2.0);
    x1 = (currentCar->_pos_X - radius - track_min_x)/tracksize;
    y1 = (currentCar->_pos_Y - radius - track_min_y)/tracksize;
    x2 = (currentCar->_pos_X + radius - track_min_x)/tracksize;
    y2 = (currentCar->_pos_Y + radius - track_min_y)/tracksize;
 
    // Draw track.
    int x = Winx + Winw + map_x - map_size;
    int y = Winy + Winh + map_y - map_size;
    glBegin(GL_QUADS);
    glTexCoord2f(x1, y1); glVertex2f(x, y);
    glTexCoord2f(x2, y1); glVertex2f(x + map_size, y);
    glTexCoord2f(x2, y2); glVertex2f(x + map_size, y + map_size);
    glTexCoord2f(x1, y2); glVertex2f(x, y + map_size);
    glEnd();
 
    // Draw car "dots".
    glDisable(GL_BLEND);
    glDisable(GL_TEXTURE_2D);
 
    if (viewmode & TRACK_MAP_PAN_WITH_OPPONENTS) {
        int i;
        for (i = 0; i < s->_ncars; i++) {
            if ((s->cars[i] != currentCar) &&
                !(s->cars[i]->_state &
                (RM_CAR_STATE_DNF | RM_CAR_STATE_PULLUP | RM_CAR_STATE_PULLSIDE | RM_CAR_STATE_PULLDN)))
            {
                if (s->cars[i]->race.pos > currentCar->race.pos) {
                    glColor4fv(behindCarColor);
                } else {
                    glColor4fv(aheadCarColor);
                }
                float xc = s->cars[i]->_pos_X - currentCar->_pos_X;
                float yc = s->cars[i]->_pos_Y - currentCar->_pos_Y;
                if (fabs(xc) < radius && fabs(yc) < radius) {
                    xc = xc/radius*map_size;
                    yc = yc/radius*map_size;
 
                    glPushMatrix();
                    glTranslatef(x + (xc + map_size)/2.0, y + (yc + map_size)/2.0, 0.0);
                    float factor = tracksize/(2.0*radius);
                    glScalef(factor, factor, 1.0);
                    glCallList(cardot);
                    glPopMatrix();
                }
            }
        }
    }
 
    glColor4fv(currentCarColor);
    if (cardot != 0) {
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glTranslatef(x + map_size/2.0, y + map_size/2.0, 0.0);
        float factor = tracksize/(2.0*radius);
        glScalef(factor, factor, 1.0);
        glCallList(cardot);
        glPopMatrix();
    }
}
 
 
// Draw the track in the panning aligned mode.
void cGrTrackMap::drawTrackPanningAligned(
    int Winx,
    int Winy,
    int Winw,
    int Winh,
    tCarElt *currentCar,
    tSituation *s
)
{
    float tracksize = MAX(track_width, track_height);
    float radius = MIN(500.0, tracksize/2.0);
 
    float x = Winx + Winw + map_x - map_size;
    float y = Winy + Winh + map_y - map_size;
    glMatrixMode(GL_TEXTURE);
    glPushMatrix();
 
    glTranslatef(
        (currentCar->_pos_X - track_min_x)/tracksize,
        (currentCar->_pos_Y - track_min_y)/tracksize,
        0.0
    );
    glRotatef(currentCar->_yaw*360.0/(2.0*PI) - 90.0, 0.0, 0.0, 1.0);
    float factor = (2.0*radius)/tracksize;
    glScalef(factor, factor, 1.0);
    glTranslatef(-0.5, -0.5, 0.0);
 
    glBegin(GL_QUADS);
    glTexCoord2f(0.0, 0.0); glVertex2f(x, y);
    glTexCoord2f(1.0, 0.0); glVertex2f(x + map_size, y);
    glTexCoord2f(1.0, 1.0); glVertex2f(x + map_size, y + map_size);
    glTexCoord2f(0.0, 1.0); glVertex2f(x, y + map_size);
    glEnd();
 
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);
 
    // Draw car "dots".
    glDisable(GL_BLEND);
    glDisable(GL_TEXTURE_2D);
 
    if (viewmode & TRACK_MAP_PAN_ALIGNED_WITH_OPPONENTS) {
        int i;
        for (i = 0; i < s->_ncars; i++) {
            if ((s->cars[i] != currentCar) && !(s->cars[i]->_state & (RM_CAR_STATE_DNF | RM_CAR_STATE_PULLUP | RM_CAR_STATE_PULLSIDE | RM_CAR_STATE_PULLDN))) {
                if (s->cars[i]->race.pos > currentCar->race.pos) {
                    glColor4fv(behindCarColor);
                } else {
                    glColor4fv(aheadCarColor);
                }
                float xc = (s->cars[i]->_pos_X - currentCar->_pos_X)/(radius*2.0)*map_size;
                float yc = (s->cars[i]->_pos_Y - currentCar->_pos_Y)/(radius*2.0)*map_size;
                float ss = sin(-currentCar->_yaw + PI/2.0);
                float cs = cos(-currentCar->_yaw + PI/2.0);
                float xrc = xc * cs - yc * ss;
                float yrc = xc * ss + yc * cs;
 
                if (fabs(xrc) < map_size/2.0 && fabs(yrc) < map_size/2.0) {
                    glPushMatrix();
                    glTranslatef(x + xrc + map_size/2.0, y + yrc + map_size/2.0, 0.0);
                    float factor = tracksize/(2.0*radius);
                    glScalef(factor, factor, 1.0);
                    glCallList(cardot);
                    glPopMatrix();
                }
            }
        }
    }
 
    glColor4fv(currentCarColor);
    if (cardot != 0) {
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glTranslatef(x + map_size/2.0, y + map_size/2.0, 0.0);
        glScalef(1.0/factor, 1.0/factor, 1.0);
        glCallList(cardot);
        glPopMatrix();
    }
}
 
 
// Draw the dot of the car.
void cGrTrackMap::drawCar(tCarElt *currentCar, GLfloat* color, int x, int y)
{
    // Compute screen coordinates of the car.
    float car_x = (currentCar->_pos_X - track_min_x)/track_width*map_size*track_x_ratio + x;
    float car_y = (currentCar->_pos_Y - track_min_y)/track_height*map_size*track_y_ratio + y;
 
    glDisable(GL_BLEND);
    glDisable(GL_TEXTURE_2D);
    glColor4fv(color);
 
    if (cardot != 0) {
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glTranslatef(car_x, car_y, 0.0);
        glCallList(cardot);
        glPopMatrix();
    }
}
 
 
// Draw all opponents of the current car.
void cGrTrackMap::drawCars(tCarElt *currentCar, tSituation *s, int x, int y)
{
    int i;
    for (i = 0; i < s->_ncars; i++) {
        if ((s->cars[i] != currentCar) &&
            !(s->cars[i]->_state &
            (RM_CAR_STATE_DNF | RM_CAR_STATE_PULLUP | RM_CAR_STATE_PULLSIDE | RM_CAR_STATE_PULLDN)))
        {
            if (s->cars[i]->race.pos > currentCar->race.pos) {
                drawCar(s->cars[i], behindCarColor, x, y);
            } else {
                drawCar(s->cars[i], aheadCarColor, x, y);
            }
        }
    }
}
 
 
// Checks if the new value is a minimum, and if true it assigns it
inline void cGrTrackMap::checkAndSetMinimum(float &currentmin, float &value)
{
    if (value < currentmin) {
        currentmin = value;
    }
    return;
}
 
 
// Checks if the new value is a maximum, and if true it assigns it
inline void cGrTrackMap::checkAndSetMaximum(float &currentmax, float &value)
{
    if (value > currentmax) {
        currentmax = value;
    }
    return;
}
 
 
// Setus up colors.
void cGrTrackMap::initColors()
{
    currentCarColor[0] = 1.0;
    currentCarColor[1] = 0.0;
    currentCarColor[2] = 0.0;
    currentCarColor[3] = 1.0;
 
    aheadCarColor[0] = 0.0;
    aheadCarColor[1] = 1.0;
    aheadCarColor[2] = 0.0;
    aheadCarColor[3] = 1.0;
 
    behindCarColor[0] = 0.0;
    behindCarColor[1] = 0.0;
    behindCarColor[2] = 1.0;
    behindCarColor[3] = 1.0;
}
 
 
// Set the view mode 
void cGrTrackMap::setViewMode(int vm) {
    viewmode = vm;
}
        
// Get The view mode
int cGrTrackMap::getViewMode() {
    return viewmode;
}
 
// Get the default view mode
int cGrTrackMap::getDefaultViewMode() {
    return TRACK_MAP_NORMAL_WITH_OPPONENTS;
}