cursorupdate() - modified by Felix-The-Ghost

...

VARP(showgrid,0,1,1);
VARP(showselborders,0,1,1);

...

void cursorupdate()                                     // called every frame from hud
{
    flrceil = ((int)(camera1->pitch>=0))*2;
    int cyaw = ((int) camera1->yaw) % 180;
    editaxis = editmode ? (fabs(camera1->pitch) > 65 ? 13 : (cyaw < 45 || cyaw > 135 ? 12 : 11)) : 0;

    volatile float x = worldpos.x;                      // volatile needed to prevent msvc7 optimizer bug?
    volatile float y = worldpos.y;
    volatile float z = worldpos.z;

    cx = (int)x;
    cy = (int)y;

    if (OUTBORD(cx, cy)) return;
    sqr *s = S(cx,cy);

    if(fabs(sheight(s,s,z)-z)>1)                        // selected wall
    {
        x += x>camera1->o.x ? 0.5f : -0.5f;             // find right wall cube
        y += y>camera1->o.y ? 0.5f : -0.5f;

        cx = (int)x;
        cy = (int)y;

        if(OUTBORD(cx, cy)) return;
    }

    if(dragging) { makesel(false); };

    const int GRIDSIZE = 5;
    const float GRIDW = 0.5f;
    const float GRID8 = 2.0f;
    const float GRIDS = 2.0f;
    const int GRIDM = 0x7;

    // render editing grid

    if(showgrid)
    {
        for(int ix = cx-GRIDSIZE; ix<=cx+GRIDSIZE; ix++) for(int iy = cy-GRIDSIZE; iy<=cy+GRIDSIZE; iy++)
        {

            if(OUTBORD(ix, iy)) continue;
            sqr *s = S(ix,iy);

            //if(SOLID(s)) continue;

            float h1 = sheight(s, s, z);
            float h2 = sheight(s, SWS(s,1,0,sfactor), z);
            float h3 = sheight(s, SWS(s,1,1,sfactor), z);
            float h4 = sheight(s, SWS(s,0,1,sfactor), z);

            /** The color of "inside" a cube? **/

            if(s->tag)
            linestyle(GRIDW, 0xFF, 0x40, 0x40); //Editing values sometimes has no effect

            /** Heightfield Style **/

            else if(s->type==FHF || s->type==CHF)
            linestyle(GRIDW, 0x80, 0xFF, 0x80); //green

            /** Solid cube style **/

            else if(SOLID(s))
            linestyle(GRID8, 0xAB, 0x40, 0xFE); //purple

            /** Normal cube style **/

            else linestyle(GRIDW, 0x80, 0x80, 0x80); //grey

            /** Actually drawing the grid **/

            block b = { ix, iy, 1, 1 }; //set destination coordinates to draw to
            box(b, h1, h2, h3, h4); //draw

            /** The repeating 8 x 8 grid **/

            /* Choosing color **/

            linestyle(GRID8, 0x40, 0x40, 0xFF); //blue

            /* Drawing lines on this grid */

            if(!(ix&GRIDM))
            line(ix, iy, h1, ix, iy+1, h4);

            if(!((ix+1)&GRIDM))
            line(ix+1, iy, h2, ix+1, iy+1, h3);

            if(!(iy&GRIDM))
            line(ix, iy, h1, ix+1, iy, h2);

            if(!((iy+1)&GRIDM))
            line(ix, iy+1, h4, ix+1, iy+1, h3);
        }

        /** Draw white square around cube cursor is over **/

        float ih = sheight(s, s, z);

        linestyle(GRIDS, 0xFF, 0xFF, 0xFF); //white

        block b = { cx, cy, 1, 1 };
        box(b, ih, sheight(s, SWS(s,1,0,sfactor), z), sheight(s, SWS(s,1,1,sfactor), z), sheight(s, SWS(s,0,1,sfactor), z));

        /** And the orienting little square in the corner **/

        linestyle(GRIDS, 0xFF, 0x00, 0x00); //red
        dot(cx, cy, ih);

        ch = (int)ih; //updates height of selection box (the red boxes) to the correct height
    }

    /** Draw selection(s) **/

    if(selset() && showselborders)
    {
        /* Choosing color */

        linestyle(GRIDS, 0xFF, 0x40, 0x40); //red

        /* Drawing */

        loopv(sels) //for each selection
        box(sels[i], (float)sels[i].h, (float)sels[i].h, (float)sels[i].h, (float)sels[i].h);
    }

    glLineWidth(1);
}