//
// Book:      OpenGL(R) ES 2.0 Programming Guide
// Authors:   Aaftab Munshi, Dan Ginsburg, Dave Shreiner
// ISBN-10:   0321502795
// ISBN-13:   9780321502797
// Publisher: Addison-Wesley Professional
// URLs:      http://safari.informit.com/9780321563835
//            http://www.opengles-book.com
//

// ESUtil.c
//
//    A utility library for OpenGL ES.  This library provides a
//    basic common framework for the example applications in the
//    OpenGL ES 2.0 Programming Guide.
//

///
//  Includes
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <sys/time.h>
#include "esUtil.h"

///
// esLogMessage()
//
//    Log an error message to the debug output for the platform
//
void ESUTIL_API esLogMessage ( const char *formatStr, ... )
{
    va_list params;
    char buf[BUFSIZ];

    va_start ( params, formatStr );
    vsprintf ( buf, formatStr, params );
    
    printf ( "%s", buf );
    
    va_end ( params );
}


///
// esLoadTGA()
//
//    Loads a 24-bit TGA image from a file. This is probably the simplest TGA loader ever.
//    Does not support loading of compressed TGAs nor TGAa with alpha channel. But for the
//    sake of the examples, this is sufficient.
//

char* ESUTIL_API esLoadTGA ( char *fileName, int *width, int *height )
{
    char *buffer = NULL;
    FILE *f;
    unsigned char tgaheader[12];
    unsigned char attributes[6];
    unsigned int imagesize;

    f = fopen(fileName, "rb");
    if(f == NULL) return NULL;

    if(fread(&tgaheader, sizeof(tgaheader), 1, f) == 0)
    {
        fclose(f);
        return NULL;
    }

    if(fread(attributes, sizeof(attributes), 1, f) == 0)
    {
        fclose(f);
        return 0;
    }

    *width = attributes[1] * 256 + attributes[0];
    *height = attributes[3] * 256 + attributes[2];
    imagesize = attributes[4] / 8 * *width * *height;
    buffer = malloc(imagesize);
    if (buffer == NULL)
    {
        fclose(f);
        return 0;
    }

    if(fread(buffer, 1, imagesize, f) != imagesize)
    {
        free(buffer);
        return NULL;
    }
    fclose(f);
    return buffer;
}

double esNow(void)
{
   struct timeval tv;
#ifdef __VMS
   (void) gettimeofday(&tv, NULL );
#else
   (void) gettimeofday(&tv, NULL);
#endif
   return tv.tv_sec * 1.0 + tv.tv_usec / 1000000.0;
}