Modified version of lib3ds reader of .3ds format

#include "Lib3ds_background.h"

#include <math.h>

Lib3ds_background::Lib3ds_background()
{
}

bool Lib3ds_background::solid_bgnd_read(Lib3dsBackground *background)
{
    Lib3dsChunk c;
    uint16_t chunk;
    int have_lin = FALSE;

    if(!lib3ds_chunk_read_start(&c, CHK_SOLID_BGND))
    {
        return false;
    }

    while ((chunk = lib3ds_chunk_read_next(&c)) != 0)
    {
        switch (chunk)
        {
            case CHK_LIN_COLOR_F:
                lib3ds_io_read_rgb(background->setting.solid_color);
                have_lin = TRUE;
                break;

            case CHK_COLOR_F:
                lib3ds_io_read_rgb(background->setting.solid_color);
                break;

            default:
                lib3ds_chunk_unknown(chunk);
        }
    }

    lib3ds_chunk_read_end(&c);

    return true;
}

bool Lib3ds_background::v_gradient_read(Lib3dsBackground *background)
{
    Lib3dsChunk c;

    uint16_t chunk;
    int index[2];
    float col[2][3][3];
    int have_lin = 0;

    if(!lib3ds_chunk_read_start(&c, CHK_V_GRADIENT))
    {
        return false;
    }

    background->setting.gradient_percent = lib3ds_io_read_float();
    lib3ds_chunk_read_tell(&c);

    index[0] = index[1] = 0;

    while ((chunk = lib3ds_chunk_read_next(&c)) != 0)
    {
        switch (chunk)
        {
            case CHK_COLOR_F:
                lib3ds_io_read_rgb(col[0][index[0]]);
                index[0]++;
                break;

            case CHK_LIN_COLOR_F:
                lib3ds_io_read_rgb(col[1][index[1]]);
                index[1]++;
                have_lin = 1;
                break;

            default:
                lib3ds_chunk_unknown(chunk);
        }
    }
    {
        int i;
        for (i = 0; i < 3; ++i)
        {
            background->setting.gradient_top[i] = col[have_lin][0][i];
            background->setting.gradient_middle[i] = col[have_lin][1][i];
            background->setting.gradient_bottom[i] = col[have_lin][2][i];
        }
    }
    lib3ds_chunk_read_end(&c);

    return true;
}


bool Lib3ds_background::lib3ds_background_read(Lib3dsBackground *background)
{
    Lib3dsChunk c;

    if(!lib3ds_chunk_read(&c))
    {
        return false;
    }

    switch (c.chunk)
    {
        case CHK_BIT_MAP:
        {
            if(!lib3ds_io_read_string(background->bitmap_name.bitmap_name, 64))
            {
                return false;
            }

            break;
        }

        case CHK_SOLID_BGND:
        {
            lib3ds_chunk_read_reset(&c);

            if(!solid_bgnd_read(background))
            {
                return false;
            }

            break;
        }

        case CHK_V_GRADIENT:
        {
            lib3ds_chunk_read_reset(&c);

            if(!v_gradient_read(background))
            {
                return false;
            }

            break;
        }

        case CHK_USE_BIT_MAP:
        {
            background->setting.use_bitmap = TRUE;
            break;
        }

        case CHK_USE_SOLID_BGND:
        {
            background->setting.use_solid = TRUE;
            break;
        }

        case CHK_USE_V_GRADIENT:
        {
            background->setting.use_gradient = TRUE;
            break;
        }
    }

    return true;
}