//
//  loadfunctions.m
//  CocoaGL
//
//  Created by kat on Sat Aug 17 2002.
//  Copyright (c) 2001 __MyCompanyName__. All rights reserved.
//

#import "loadfunctions.h"


@implementation loadfunctions

@end

void   Error(const char* errorloc)
{
    int a;
    if( (a=glGetError())!=0 ) 
    { 
        if( a == GL_INVALID_ENUM )
            NSLog(@"In %s: GL_INVALID_ENUM", errorloc);
        else if( a == GL_INVALID_VALUE )
            NSLog(@"In %s: GL_INVALID_VALUE", errorloc);
        else if( a == GL_INVALID_OPERATION )
            NSLog(@"In %s: GL_INVALID_OPERATION", errorloc);
        else if( a = GL_STACK_OVERFLOW )
            NSLog(@"In %s: GL_STACK_OVERFLOW", errorloc);
        else if( a == GL_STACK_UNDERFLOW )
            NSLog(@"In %s: GL_STACK_UNDERFLOW", errorloc);
        else if( a == GL_OUT_OF_MEMORY )
            NSLog(@"In %s: GL_OUT_OF_MEMORY", errorloc);
        else if( a == GL_TABLE_TOO_LARGE )
            NSLog(@"In %s: GL_TABLE_TOO_LARGE", errorloc);
    }
}

// my jpgs stopped working....
GLuint getTextures( NSString *location )
{
    NSURL   *theURL;
    NSImage *theImage;
    GLuint   theTexture;
    
    NSLog(@"start getting the image");
    // get the URL for the star image
    // the application is in the build directory, one level up from our star
    theURL   = [[NSURL alloc] initFileURLWithPath: location];
    if( theURL != nil )
        NSLog(@"NSURL != nil");
    else
        NSLog(@"the URL was invalid");
    // load the star from the file
    theImage = [[NSImage alloc] initWithContentsOfURL: theURL ];
    [theImage setName:@"NSGLParticleEnginePicture"];
    
    // generate the texture objects references
    glGenTextures( 1, &theTexture );
    Error("getTextures");
    
    glBindTexture( GL_TEXTURE_2D, theTexture );
    loadPicture( @"NSGLParticleEnginePicture" );

    // release the memory that was allocated
    [theURL release];
    [theImage release];
    
    return theTexture;
}






void loadPicture( NSString *name )
{
    NSBitmapImageRep *bitmap;
    NSImage *image; 
        
    // initialize the image to the correct file (name)
    image = [ NSImage imageNamed: name ];
    if( image == nil )
        { NSLog(@"image == nil"); return; }

    // create a bitmap with the correct image data
    bitmap = [[NSBitmapImageRep alloc]initWithData: [image TIFFRepresentation]];

    // if this bitmap is null, we should really free the texture
    if (bitmap == nil)
        { NSLog(@"in LoadGLTextures : NSBitmapImageRep not loaded"); [bitmap release]; return; }

    // we are aligned by BYTES in an NSBitmapImageRep
    glPixelStorei(GL_UNPACK_ALIGNMENT,   1   );
    Error("loadPicture glPixelStorei");
    
    // put the image into texture memory
    // the image has Red-Green-Blue-Alpha chanels, is width*height in size
    // and is made up of unsigned bytes
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 
                [bitmap size].width, [bitmap size].height, 0, 
                GL_RGB, GL_UNSIGNED_BYTE, [bitmap bitmapData]);
    Error("loadPicture glTexImage2D");
    NSLog(@"width = %d, height = %d",[bitmap size].width, [bitmap size].height);
    
    // when we make the image smaller, use a linear filter on this texture
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    Error("loadPicture glTexParameteri GL_TEXTURE_MIN_FILTER");
    
    // when we magnify the image, use a linear filter on this texture
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    Error("loadPicture glTexParameteri GL_TEXTURE_MAG_FILTER");
    
    // let the bitmap go
    [bitmap release];
}