/*****************************************************************
  motionblur.cpp
  by Dave Pape
  20 April 2003

*****************************************************************/
#include <stdlib.h>
#include <math.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <dms/dms.h>

#define BLUR_TIME_SPREAD 0.1

#define NUM_PASSES 16

using namespace dms;

void createScene(Object& root);
void drawEverything(void);
void accumulate(bool firstImage, bool lastImage);
void displayAccumulation(void);
void bounceBall(dms::Object&,void *);
void bounceBall2(dms::Object&,void *);

void key(unsigned char k, int x, int y);
void specialkey(int k, int x, int y);
void idle(void);


PerspCamera camera;
Light light;
Object root;

GLuint textureID;


int main(int argc, char *argv[])
    {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(512,512);
    glutCreateWindow(argv[0]);
    
    glutDisplayFunc(drawEverything);
    glutKeyboardFunc(key);
    glutSpecialFunc(specialkey);
    glutIdleFunc(idle);
    
    camera.setPosition(0, 0, 18);
    light.setInfinitePosition(1, 1, 2);
    createScene(root);
    
    glutMainLoop();
    return 0;
    }


#define TEX_HEIGHT 512
#define TEX_WIDTH 512
struct _color { GLubyte r,g,b; };

struct _color textureImage[TEX_HEIGHT][TEX_WIDTH];


void createScene(Object& root)
    {
    QuadricObject * quadric;
    Square * square;
    Material * material;
    SimpleTransform * transform;
    
    quadric = new QuadricObject;
    quadric->makeSphere(2.5, 24, 12);
    material = new Material(Color::Yellow);
    quadric->setMaterial(*material);
    transform = new SimpleTransform;
    transform->setTranslation(-4, 0, -3);
    quadric->setTransform(*transform);
    quadric->setUpdateCallback(bounceBall);
    root.attach(*quadric);
    
    quadric = new QuadricObject;
    quadric->makeSphere(2.5, 24, 12);
    material = new Material(Color::Blue);
    quadric->setMaterial(*material);
    transform = new SimpleTransform;
    transform->setTranslation(4, 0, -3);
    quadric->setTransform(*transform);
    quadric->setUpdateCallback(bounceBall2);
    root.attach(*quadric);
    
    quadric = new QuadricObject;
    quadric->makeCone(1.0, 14.0, 24, 1, DMS_Y);
    material = new Material(Color::White);
    quadric->setMaterial(*material);
    transform = new SimpleTransform;
    transform->setTranslation(0, -10, 0);
    quadric->setTransform(*transform);
    root.attach(*quadric);
    
    square = new Square(-10, -10, 10, 10, DMS_Y);
    material = new Material(Color::Green);
    square->setMaterial(*material);
    transform = new SimpleTransform;
    transform->setTranslation(0, -10, 0);
    square->setTransform(*transform);
    root.attach(*square);

    memset(textureImage, 0, sizeof(textureImage));
    glGenTextures(1, &textureID);
    glBindTexture(GL_TEXTURE_2D, textureID);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, TEX_WIDTH, TEX_HEIGHT,
                 0, GL_RGB, GL_UNSIGNED_BYTE, textureImage);
    glBindTexture(GL_TEXTURE_2D, 0);
    }


float updateTime=0;

void drawEverything(void)
    {
    updateTime = currentTime() - BLUR_TIME_SPREAD/2.0;
    
    glEnable(GL_DEPTH_TEST);
    
    for (int i=0; i < NUM_PASSES; i++)
        {
        glClearColor(0.5, 0.7, 1.0, 0.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        camera.apply();
        light.apply();
        root.drawAll();
        updateTime += BLUR_TIME_SPREAD / NUM_PASSES;
        root.updateAll();
        accumulate(i==0, i==NUM_PASSES-1);
        }

    glutSwapBuffers();
    checkGLError("end-of-frame");
    }


void accumulate(bool firstImage, bool lastImage)
    {
    glEnable(GL_BLEND);
    if (firstImage)
        glBlendFunc(GL_ZERO, GL_SRC_ALPHA);
    else
        glBlendFunc(GL_ONE, GL_SRC_ALPHA);
    glColor4f(1, 1, 1, 1.0/NUM_PASSES);
    displayAccumulation();
    glDisable(GL_BLEND);
    glEnable(GL_DEPTH_TEST);
    if (!lastImage)
        {
        glBindTexture(GL_TEXTURE_2D, textureID);
        glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, TEX_WIDTH, TEX_HEIGHT, 0);
        glBindTexture(GL_TEXTURE_2D, 0);
        }
    }


void displayAccumulation(void)
    {
    glDisable(GL_DEPTH_TEST);
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    glOrtho(0, 1, 0, 1, -1, 1);
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, textureID);
    glBegin(GL_QUADS);
     glTexCoord2i(0,0);
     glVertex2i(0,0);
     glTexCoord2i(1,0);
     glVertex2i(1,0);
     glTexCoord2i(1,1);
     glVertex2i(1,1);
     glTexCoord2i(0,1);
     glVertex2i(0,1);
    glEnd();
    glDisable(GL_TEXTURE_2D);
    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();
    }


void bounceBall(dms::Object& object,void *)
    {
    dms::SimpleTransform& xform = (dms::SimpleTransform&)object.transform();
    float y = fabs(sin(updateTime) * 10) - 10;
    xform.setTranslation(-4, y, -3);
    }


void bounceBall2(dms::Object& object,void *)
    {
    dms::SimpleTransform& xform = (dms::SimpleTransform&)object.transform();
    float y = fabs(sin(updateTime*3) * 10) - 10;
    xform.setTranslation(4, y, -3);
    }


void key(unsigned char k, int x, int y)
    {
    if (k == 27)
        exit(0);
    }


void specialkey(int k, int x, int y)
    {
    if (k == GLUT_KEY_LEFT)
        camera.turn(1);
    else if (k == GLUT_KEY_RIGHT)
        camera.turn(-1);
    else if (k == GLUT_KEY_UP)
        camera.pitch(1);
    else if (k == GLUT_KEY_DOWN)
        camera.pitch(-1);
    else if (k == GLUT_KEY_HOME)
        camera.moveForward(0.25);
    else if (k == GLUT_KEY_END)
        camera.moveForward(-0.25);
    else if (k == GLUT_KEY_PAGE_UP)
        camera.zoom(-1);
    else if (k == GLUT_KEY_PAGE_DOWN)
        camera.zoom(1);
    }


void idle(void)
    {
    root.updateAll();
    glutPostRedisplay();
    }