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*/

#import "DemoGLOverlayView.h"

#import <OpenGL/gl.h>

@implementation DemoGLOverlayView

- (id)initWithFrame:(NSRect)frame

{

    NSOpenGLPixelFormatAttribute attribs[] = 

        {NSOpenGLPFAAccelerated,

        NSOpenGLPFADoubleBuffer,

        0};

    NSOpenGLPixelFormat *fmt;

    /* Choose a pixel format */

    fmt = [[NSOpenGLPixelFormat alloc] initWithAttributes:attribs];

    /* Create a GL context */

    self = [super initWithFrame:frame];

    openGLContext = [[NSOpenGLContext alloc] initWithFormat:fmt shareContext:nil];

    [[NSNotificationCenter defaultCenter]

        addObserver:self

        selector:@selector(globalFrameChanged:)

        name:NSViewGlobalFrameDidChangeNotification

        object:self];

    /* Destroy the pixel format */

    [fmt release];

    if(self)

    {

        long opaque = 0;

        [openGLContext setValues:&opaque forParameter:NSOpenGLCPSurfaceOpacity];        

    }

    return self;

}

- (void)animate:(NSTimer *)timer

{

    glNeedsDisplay = YES;

    [super animate:timer];

}

- (BOOL)isOpaque

{

    return glNeedsDisplay;

}

- (void)vewWillMoveToWindow:(NSWindow *)window

{

    if(window != [self window])

        [openGLContext clearDrawable];

}

- (void)viewDidMoveToWindow

{

    if([self window])

        [openGLContext setView:self];

}

- (void)globalFrameChanged:(NSNotification *)note

{

    [openGLContext update];

}

- (void)drawRect:(NSRect)rect 

{

    NSRect bounds = [self bounds];

    int i;

    // Drawing code here.

    if(!glNeedsDisplay)

    {

    [[NSColor clearColor] set];

    NSRectFill(bounds);

    }

    [openGLContext makeCurrentContext];

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

    glClearColor(0,0,0,0);

    glClear(GL_COLOR_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glOrtho(0,bounds.size.width,0,bounds.size.height,-1,1);

    glEnable(GL_BLEND);

    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    glEnable(GL_LINE_SMOOTH);

    glBegin(GL_LINES);

    for(i = 0; i < NUM_LINES; i++)

    {

    float f = (i+1)/(double)NUM_LINES;

    glColor4f(1.0f,1.0f*f,0.0f,1.0f*f);

    glVertex2f(lines[i][0].x,lines[i][0].y);

    glVertex2f(lines[i][1].x,lines[i][1].y);    

    }

    glEnd();

    glDisable(GL_LINE_SMOOTH);

    if(doSelection)

    {

        float minX, maxX, minY, maxY;

        minX = MIN(selectionBeginPoint.x,selectionEndPoint.x);

        maxX = MAX(selectionBeginPoint.x,selectionEndPoint.x);

        minY = MIN(selectionBeginPoint.y,selectionEndPoint.y);

        maxY = MAX(selectionBeginPoint.y,selectionEndPoint.y);

    glColor4f(0.0f,0.0f,1.0f,0.3f);

    glRectf(minX,minY,maxX,maxY);

    glColor4f(1.0f,1.0f,1.0f,0.8f);

    glBegin(GL_LINE_LOOP);

    glVertex2f(minX+0.5f,minY+0.5f);

    glVertex2f(maxX-0.5f,minY+0.5f);

    glVertex2f(maxX-0.5f,maxY-0.5f);

    glVertex2f(minX+0.5f,maxY-0.5f);

    glEnd();

    }    

    if(glNeedsDisplay)

    [openGLContext flushBuffer];

    else

    glFlush();

    glNeedsDisplay = NO;

    [NSOpenGLContext clearCurrentContext];

}

@end