util.h

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/* xoreos - A reimplementation of BioWare's Aurora engine
 *
 * xoreos is the legal property of its developers, whose names
 * can be found in the AUTHORS file distributed with this source
 * distribution.
 *
 * xoreos is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or (at your option) any later version.
 *
 * xoreos is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with xoreos. If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef GRAPHICS_IMAGES_UTIL_H
#define GRAPHICS_IMAGES_UTIL_H

#include <cassert>
#include <cstring>

#include "src/common/types.h"
#include "src/common/scopedptr.h"
#include "src/common/util.h"
#include "src/common/maths.h"
#include "src/common/error.h"

#include "src/graphics/types.h"

namespace Graphics {

static inline uint32 getDataSize(PixelFormatRaw format, int32 width, int32 height) {
    if ((width < 0) || (width >= 0x8000) || (height < 0) || (height >= 0x8000))
        throw Common::Exception("Invalid dimensions %dx%d", width, height);

    switch (format) {
        case kPixelFormatRGB8:
            return width * height * 3;

        case kPixelFormatRGBA8:
            return width * height * 4;

        case kPixelFormatRGB5A1:
        case kPixelFormatRGB5:
            return width * height * 2;

        case kPixelFormatDXT1:
            return MAX<uint32>( 8, ((width + 3) / 4) * ((height + 3) / 4) *  8);

        case kPixelFormatDXT3:
        case kPixelFormatDXT5:
            return MAX<uint32>(16, ((width + 3) / 4) * ((height + 3) / 4) * 16);

        default:
            break;
    }

    throw Common::Exception("Invalid pixel format %u", (uint) format);
}

static inline bool hasValidDimensions(PixelFormatRaw format, int32 width, int32 height) {
    if ((width < 0) || (width >= 0x8000) || (height < 0) || (height >= 0x8000))
        return false;

    switch (format) {
        case kPixelFormatRGB8:
        case kPixelFormatRGBA8:
        case kPixelFormatRGB5A1:
        case kPixelFormatRGB5:
        case kPixelFormatDXT1:
        case kPixelFormatDXT3:
        case kPixelFormatDXT5:
            return true;

        default:
            break;
    }

    return false;
}

static inline void flipHorizontally(byte *data, int width, int height, int bpp) {
    if ((width <= 0) || (height <= 0) || (bpp <= 0))
        return;

    const size_t halfWidth = width / 2;
    const size_t pitch     = bpp * width;

    Common::ScopedArray<byte> buffer(new byte[bpp]);

    while (height-- > 0) {
        byte *dataStart = data;
        byte *dataEnd   = data + pitch - bpp;

        for (size_t j = 0; j < halfWidth; j++) {
            memcpy(buffer.get(), dataStart   , bpp);
            memcpy(dataStart   , dataEnd     , bpp);
            memcpy(dataEnd     , buffer.get(), bpp);

            dataStart += bpp;
            dataEnd   -= bpp;
        }

        data += pitch;
    }
}

static inline void flipVertically(byte *data, int width, int height, int bpp) {
    if ((width <= 0) || (height <= 0) || (bpp <= 0))
        return;

    const size_t pitch = bpp * width;

    byte *dataStart = data;
    byte *dataEnd   = data + (pitch * height) - pitch;

    Common::ScopedArray<byte> buffer(new byte[pitch]);

    size_t halfHeight = height / 2;
    while (halfHeight--) {
        memcpy(buffer.get(), dataStart   , pitch);
        memcpy(dataStart   , dataEnd     , pitch);
        memcpy(dataEnd     , buffer.get(), pitch);

        dataStart += pitch;
        dataEnd   -= pitch;
    }
}

static inline void rotate90(byte *data, int width, int height, int bpp, int steps) {
    if ((width <= 0) || (height <= 0) || (bpp <= 0))
        return;

    assert(width == height);

    while (steps-- > 0) {
        const size_t n = width;

        const size_t w =  n      / 2;
        const size_t h = (n + 1) / 2;

        for (size_t x = 0; x < w; x++) {
            for (size_t y = 0; y < h; y++) {
                const size_t d0 = ( y          * n +  x         ) * bpp;
                const size_t d1 = ((n - 1 - x) * n +  y         ) * bpp;
                const size_t d2 = ((n - 1 - y) * n + (n - 1 - x)) * bpp;
                const size_t d3 = ( x          * n + (n - 1 - y)) * bpp;

                for (size_t p = 0; p < (size_t) bpp; p++) {
                    const byte tmp = data[d0 + p];

                    data[d0 + p] = data[d1 + p];
                    data[d1 + p] = data[d2 + p];
                    data[d2 + p] = data[d3 + p];
                    data[d3 + p] = tmp;
                }
            }
        }

    }
}

static inline uint32 deSwizzleOffset(uint32 x, uint32 y, uint32 width, uint32 height) {
    width  = Common::intLog2(width);
    height = Common::intLog2(height);

    uint32 offset     = 0;
    uint32 shiftCount = 0;

    while (width | height) {
        if (width) {
            offset |= (x & 0x01) << shiftCount;

            x >>= 1;

            shiftCount++;
            width--;
        }

        if (height) {
            offset |= (y & 0x01) << shiftCount;

            y >>= 1;

            shiftCount++;
            height--;
        }
    }

    return offset;
}

} // End of namespace Graphics

#endif // GRAPHICS_IMAGES_UTIL_H