dwscr/ss/LightBounce.cc

/* Author: Josh Holtrop
 * DornerWorks screensaver
 */

#include <GL/gl.h>
#include <GL/glu.h>
#include "LightBounce.h"

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define SIZE 5
#define STRIDE_MULTIPLIER 1.0;
#define ZOOM 12.0

LightBounceBox::LightBounceBox(LogoBox * lb,
                               float x, float y, float z,
                               float xr, float yr, float zr)
{
    this->x = x;
    this->y = y;
    this->z = z;
    this->xr = xr;
    this->yr = yr;
    this->zr = zr;
    this->dist = 0.0;

    m_dl = glGenLists(1);
    glNewList(m_dl, GL_COMPILE);
        glPushMatrix();
        glTranslatef(x, y, z);
        glRotatef(xr, 1, 0, 0);
        glRotatef(yr, 0, 1, 0);
        glRotatef(zr, 0, 0, 1);
        lb->draw();
        glPopMatrix();
    glEndList();
}

LightBounceBox::~LightBounceBox()
{
    glDeleteLists(m_dl, 1);
}

void LightBounceBox::updateDist(float x, float y, float z)
{
    float dx = x - this->x;
    float dy = y - this->y;
    float dz = z - this->z;
    this->dist = (dx*dx) + (dy*dy) + (dz*dz);
}


bool LightBounceBoxComparator::operator()(LightBounceBox * l1, LightBounceBox * l2)
{
    return l1->getDist() > l2->getDist();
}


/* construct screensaver mode and do some basic OpenGL setup */
LightBounce::LightBounce(SSMain * _SSMain) : SSMode(_SSMain)
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0,
                   (double)m_SSMain->getWidth()
                     / (double)m_SSMain->getHeight()
                     / (double)m_SSMain->getNumMonitors(),
                   0.01,
                   1000.01);
    glMatrixMode(GL_MODELVIEW);

    float box_stride = m_logoBox.getWidth() * STRIDE_MULTIPLIER;
    float half_size = SIZE * box_stride / 2.0;
    float y = -half_size + box_stride / 2.0;
    int rot = false;
    for (int i = 0; i < SIZE; i++)
    {
        float x = -half_size + box_stride / 2.0;
        for (int j = 0; j < SIZE; j++)
        {
            // front
            LightBounceBox * box = new LightBounceBox(
                &m_logoBox, x, y, -half_size, 0, 180.0, rot ? 90.0 : 0
            );
            m_boxes.push_back(box);
            // right
            box = new LightBounceBox(
                &m_logoBox, half_size, y, x, 0, 90.0, rot ? 0 : 90.0
            );
            m_boxes.push_back(box);
            // back
            box = new LightBounceBox(
                &m_logoBox, x, y, half_size, 0, 0, rot ? 90.0 : 0
            );
            m_boxes.push_back(box);
            // left
            box = new LightBounceBox(
                &m_logoBox, -half_size, y, x, 0, 270.0, rot ? 0 : 90.0
            );
            m_boxes.push_back(box);
            // top
            box = new LightBounceBox(
                &m_logoBox, x, half_size, y, 270, 0, rot ? 0 : 90.0
            );
            m_boxes.push_back(box);
            // bottom
            box = new LightBounceBox(
                &m_logoBox, x, -half_size, y, 90, 0, rot ? 0 : 90.0
            );
            m_boxes.push_back(box);

            rot = !rot;
            x += box_stride;
        }
        y += box_stride;
    }

    glPushAttrib(GL_POLYGON_BIT);   /* store CULL_FACE settings */
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
#if 0
    GLuint tex;
    glGenTextures(1, &tex);
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, tex);
    GLfloat pixels[] = {0, 0, 0, 0.5};
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_FLOAT, pixels);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
#endif
    glEnable(GL_COLOR_MATERIAL);
    glColor4f(1, 1, 1, 0.3);
}

LightBounce::~LightBounce()
{
    glPopAttrib();
    int sz = m_boxes.size();
    for (int i = 0; i < sz; i++)
        delete m_boxes[i];
}

/* called every time this screensaver mode should redraw the screen */
void LightBounce::update()
{
    SSMode::update();
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    int numMonitors = m_SSMain->getNumMonitors();
    int width = m_SSMain->getWidth();
    int height = m_SSMain->getHeight();

    /* update the viewer position */
    double angle = m_elapsed/3700.0f;
    double viewer_dist = SIZE * ZOOM;
    float viewer_x = viewer_dist * cos(angle);
    float viewer_z = viewer_dist * sin(angle);
    float viewer_y = SIZE * ZOOM * 2.0 / 3.0;

    for (int i = 0, sz = m_boxes.size(); i < sz; i++)
    {
        m_boxes[i]->updateDist(viewer_x, viewer_y, viewer_z);
    }
    sort(m_boxes.begin(), m_boxes.end(), m_comparator);

    for (int i = 0; i < numMonitors; i++)
    {
        glViewport(i*width/numMonitors, 0, width/numMonitors, height);
        glLoadIdentity();
        gluLookAt(viewer_x, viewer_y, viewer_z, 0, 0, 0, 0, 1, 0);
        for (int i = 0, sz = m_boxes.size(); i < sz; i++)
        {
            m_boxes[i]->draw();
        }
    }
    SDL_GL_SwapBuffers();
}