Trail.cpp

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/*  Project Starshatter 4.5
        Destroyer Studios LLC
        Copyright © 1997-2004. All Rights Reserved.

        SUBSYSTEM:    Stars.exe
        FILE:         Trail.cpp
        AUTHOR:       John DiCamillo


        OVERVIEW
        ========
        Missile Trail representation class
*/

#include "MemDebug.h"
#include "Trail.h"
#include "Weapon.h"
#include "Sim.h"

#include "Game.h"
#include "Light.h"
#include "Bitmap.h"
#include "DataLoader.h"
#include "Sound.h"

// +--------------------------------------------------------------------+

Trail::Trail(Bitmap* tex, int n)
: ntrail(0), length0(0), length1(0), texture(tex), maxtrail(n), dim(1)
{
        trans    = true;
        luminous = true;

        mtl.Kd            = Color::White;
        mtl.tex_diffuse   = texture;
        mtl.tex_emissive  = texture;
        mtl.blend         = Video::BLEND_ADDITIVE;
        mtl.luminous      = true;

        if (maxtrail < 4) maxtrail = 512;
        trail = new(__FILE__,__LINE__) Point[maxtrail];
        verts = new(__FILE__,__LINE__) VertexSet(maxtrail*2);
        verts->Clear();
        verts->nverts = 0;

        for (int i = 0; i < maxtrail*2; i++) {
                verts->diffuse[i]  = D3DCOLOR_RGBA(255,255,255,255);
                verts->specular[i] = D3DCOLOR_RGBA(  0,  0,  0,255);
                verts->tu[i]       = 0.0f;
                verts->tv[i]       = (i & 1) ? 1.0f : 0.0f;
        }

        polys = new(__FILE__,__LINE__) Poly[maxtrail];

        for (int i = 0; i < maxtrail; i++) {
                polys[i].vertex_set  = verts;
                polys[i].nverts      = 4;
                polys[i].material    = &mtl;
        }

        npolys = 0;
        nverts = 0;
        width  = 6;
        length = 0;
        dim    = 3;

        last_point_time = 0;
}

Trail::~Trail()
{
        delete [] trail;
        delete [] polys;
        delete    verts;
}

void
Trail::UpdateVerts(const Point& cam_pos)
{
        if (ntrail < 2) return;

        int bright = 255 - dim*ntrail;

        Point head  = trail[1] + loc;
        Point tail  = trail[0] + loc;
        Point vcam  = cam_pos - head;
        Point vtmp  = vcam.cross(head-tail);
        vtmp.Normalize();
        Point vlat  = vtmp * (width + (0.1 * width * ntrail));

        verts->loc[0]     = tail - vlat;
        verts->loc[1]     = tail + vlat;
        verts->diffuse[0] = 0;
        verts->diffuse[1] = 0;

        for (int i = 0; i < ntrail-1; i++) {
                bright+=dim;
                Point head  = trail[i+1] + loc;
                Point tail  = trail[i] + loc;
                Point vcam  = cam_pos - head;
                Point vtmp  = vcam.cross(head-tail);
                vtmp.Normalize();
                
                float trail_width = (float) (width + (ntrail-i) * width * 0.1);
                if (i == ntrail-2) trail_width = (float) (width * 0.7);
                Point vlat  = vtmp * trail_width;

                verts->loc[2*i+2] = head - vlat;
                verts->loc[2*i+3] = head + vlat;

                if (bright <= 0) {
                        verts->diffuse[2*i+2] = 0;
                        verts->diffuse[2*i+3] = 0;
                }
                else {
                        verts->diffuse[2*i+2] = D3DCOLOR_RGBA(bright,bright,bright,bright);
                        verts->diffuse[2*i+3] = D3DCOLOR_RGBA(bright,bright,bright,bright);
                }
        }
}

void
Trail::Render(Video* video, DWORD flags)
{
        if (!npolys) return;

        if ((flags & RENDER_ADDITIVE) == 0)
        return;

        if (video && life) {
                const Camera* cam = video->GetCamera();

                if (cam)
                UpdateVerts(cam->Pos());

                video->DrawPolys(npolys, polys);
        }
}

void
Trail::AddPoint(const Point& v)
{
        if (ntrail >= maxtrail-1) return;

        double real_time = Game::RealTime() / 1000.0;

        if (ntrail == 0) {
                radius   = 1000;
        }
        else {
                radius   = (float) Point(v-loc).length();
        }

        // just adjust the last point:
        if (ntrail > 1 && real_time - last_point_time < 0.05) {
                trail[ntrail-1] = v;
        }

        // add a new point:
        else {
                last_point_time = real_time;
                trail[ntrail++] = v;

                nverts += 2;
                verts->nverts = nverts;

                if (ntrail > 1) {
                        length0 = length1;
                        length1 = length0 + (trail[ntrail-1]-trail[ntrail-2]).length();

                        polys[npolys].vertex_set = verts;
                        polys[npolys].nverts = 4;

                        polys[npolys].verts[0] = nverts-4;
                        polys[npolys].verts[1] = nverts-2;
                        polys[npolys].verts[2] = nverts-1;
                        polys[npolys].verts[3] = nverts-3;

                        float tu1 =  (float) length1 / 250.0f;

                        verts->tu[2*ntrail-1] = tu1;
                        verts->tu[2*ntrail-2] = tu1;

                        npolys++;
                }
        }
}

double
Trail::AverageLength()
{
        double avg = 0;

        for (int i = 0; i < ntrail-1; i++)
        avg += (trail[i+1]-trail[i]).length();
        avg /= ntrail;

        return avg;
}