/*

     File: Scene.m

 Abstract:  A delegate object used by MyOpenGLView and MainController to 

 render a simple scene.

  Version: 1.1

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*/

#import "Scene.h"

#import "Texture.h"

#import <OpenGL/glu.h>

static double dtor( double degrees )

{

    return degrees * M_PI / 180.0;

}

@implementation Scene

- (id) init

{

    self = [super init];

    if (self) {

        textureName = 0;

        animationPhase = 0.0;

        rollAngle = 0.0;

        sunAngle = 135.0;

        wireframe = NO;

    } 

    return self;

}

- (void)dealloc

{

    [texture release];

    [super dealloc];

}

- (float)rollAngle

{

    return rollAngle;

}

- (void)setRollAngle:(float)newRollAngle

{

    rollAngle = newRollAngle;

}

- (float)sunAngle

{

    return sunAngle;

}

- (void)setSunAngle:(float)newSunAngle

{

    sunAngle = newSunAngle;

}

- (void)advanceTimeBy:(float)seconds

{

    float phaseDelta = seconds - floor(seconds);

    float newAnimationPhase = animationPhase + 0.015625 * phaseDelta;

    newAnimationPhase = newAnimationPhase - floor(newAnimationPhase);

    [self setAnimationPhase:newAnimationPhase];

}

- (void)setAnimationPhase:(float)newAnimationPhase

{

    animationPhase = newAnimationPhase;

}

- (void)toggleWireframe

{

    wireframe = !wireframe;

}

- (void)setViewportRect:(NSRect)bounds

{

    glViewport(0, 0, bounds.size.width, bounds.size.height);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    gluPerspective(30, bounds.size.width / bounds.size.height, 1.0, 1000.0);

    glMatrixMode(GL_MODELVIEW);

}

// This method renders our scene.

// We could optimize it in any of several ways, including factoring out the repeated OpenGL initialization calls and 

// hanging onto the GLU quadric object, but the details of how it's implemented aren't important here. 

// The main thing to note is that we've factored the drawing code out of the NSView subclass so that

// the full-screen and non-fullscreen views share the same states for rendering 

// (and MainController can use it when rendering in full-screen mode on pre-10.6 systems).

- (void)render

{   

    static GLfloat lightDirection[] = { -0.7071, 0.0, 0.7071, 0.0 };

    static GLfloat radius = 0.25;

    static GLfloat materialAmbient[4] = { 0.0, 0.0, 0.0, 0.0 };

    static GLfloat materialDiffuse[4] = { 1.0, 1.0, 1.0, 1.0 };

    GLUquadric *quadric = NULL;

    glEnable(GL_DEPTH_TEST);

    glEnable(GL_CULL_FACE);

    glEnable(GL_LIGHTING);

    glEnable(GL_LIGHT0);

    glEnable(GL_TEXTURE_2D);

    glClearColor(0, 0, 0, 0);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Upload the texture

    // Since we are sharing OpenGL objects between the full-screen and non-fullscreen contexts, we only need to do this once

    if (!textureName) {

        NSString *path = [[NSBundle mainBundle] pathForResource:@"Earth" ofType:@"jpg"];

        texture = [[Texture alloc] initWithPath:path];

        textureName = [texture textureName];

    }

    // Set up texturing parameters

    glBindTexture(GL_TEXTURE_2D, textureName);

    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

    // Set up our single directional light (the Sun!)

    lightDirection[0] = cos(dtor(sunAngle));

    lightDirection[2] = sin(dtor(sunAngle));

    glLightfv(GL_LIGHT0, GL_POSITION, lightDirection);

    glPushMatrix();

    // Back the camera off a bit

    glTranslatef(0.0, 0.0, -1.5);

    // Draw the Earth!

    quadric = gluNewQuadric();

    if (wireframe)

        gluQuadricDrawStyle(quadric, GLU_LINE);

    gluQuadricTexture(quadric, GL_TRUE);

    glMaterialfv(GL_FRONT, GL_AMBIENT, materialAmbient);

    glMaterialfv(GL_FRONT, GL_DIFFUSE, materialDiffuse);

    glRotatef(rollAngle, 1.0, 0.0, 0.0);

    glRotatef(-23.45, 0.0, 0.0, 1.0); // Earth's axial tilt is 23.45 degrees from the plane of the ecliptic

    glRotatef(animationPhase * 360.0, 0.0, 1.0, 0.0);

    glRotatef(-90.0, 1.0, 0.0, 0.0);

    gluSphere(quadric, radius, 48, 24);

    gluDeleteQuadric(quadric);

    quadric = NULL;

    glPopMatrix();

    glBindTexture(GL_TEXTURE_2D, 0);

}

@end