surface.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef AGS_LIB_ALLEGRO_SURFACE_H
#define AGS_LIB_ALLEGRO_SURFACE_H

#include "graphics/managed_surface.h"
#include "ags/lib/allegro/base.h"
#include "ags/lib/allegro/color.h"
#include "common/array.h"

namespace AGS3 {

class BITMAP {
private:
    Graphics::ManagedSurface *_owner;
    public:
    int16 &w, &h;
    int32 &pitch;
    Graphics::PixelFormat &format;
    bool clip;
    int ct, cb, cl, cr;
    Common::Array<byte *> line;
public:
    BITMAP(Graphics::ManagedSurface *owner);
    virtual ~BITMAP() {
    }

    Graphics::ManagedSurface &operator*() const {
        return *_owner;
    }
    Graphics::ManagedSurface &getSurface() {
        return *_owner;
    }
    const Graphics::ManagedSurface &getSurface() const {
        return *_owner;
    }

    unsigned char *getPixels() const {
        return (unsigned char *)_owner->getPixels();
    }

    unsigned char *getBasePtr(uint16 x, uint16 y) const {
        return (unsigned char *)_owner->getBasePtr(x, y);
    }

    uint getTransparentColor() const {
        // See allegro bitmap_mask_color
        // For paletted sprites this is 0.
        // For other color depths this is bright pink (RGB 255, 0, 255) with alpha set to 0.
        if (format.bytesPerPixel == 1)
            return 0;
        return format.ARGBToColor(0, 255, 0, 255);
    }

    inline const Common::Point getOffsetFromOwner() const {
        return _owner->getOffsetFromOwner();
    }

    int getpixel(int x, int y) const;

    void clear() {
        _owner->clear();
    }

    void makeOpaque();

    void circlefill(int x, int y, int radius, int color);

    void floodfill(int x, int y, int color);

    void hLine(int x, int y, int x2, uint32 color) {
        _owner->hLine(x, y, x2, color);
    }

    void vLine(int x, int y, int y2, uint32 color) {
        _owner->vLine(x, y, y2, color);
    }

    void draw(const BITMAP *srcBitmap, const Common::Rect &srcRect,
              int dstX, int dstY, bool horizFlip, bool vertFlip,
              bool skipTrans, int srcAlpha, int tintRed = -1, int tintGreen = -1,
              int tintBlue = -1);

    void stretchDraw(const BITMAP *srcBitmap, const Common::Rect &srcRect,
                     const Common::Rect &destRect, bool skipTrans, int srcAlpha);

    inline bool isSubBitmap() const {
        return _owner->disposeAfterUse() == DisposeAfterUse::NO;
    }

    private:
    // True color blender functions
    // In Allegro all the blender functions are of the form
    // unsigned int blender_func(unsigned long x, unsigned long y, unsigned long n)
    // when x is the sprite color, y the destination color, and n an alpha value

    void blendPixel(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha, bool useTint, byte *destVal) const;

    inline void rgbBlend(uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Note: the original's handling varies slightly for R & B vs G.
        // We need to exactly replicate it to ensure Lamplight City's
        // calendar puzzle works correctly
        if (alpha)
            alpha++;

        uint32 x = ((uint32)rSrc << 16) | ((uint32)gSrc << 8) | (uint32)bSrc;
        uint32 y = ((uint32)rDest << 16) | ((uint32)gDest << 8) | (uint32)bDest;

        uint32 res = ((x & 0xFF00FF) - (y & 0xFF00FF)) * alpha / 256 + y;
        y &= 0xFF00;
        x &= 0xFF00;
        uint32 g = (x - y) * alpha / 256 + y;

        rDest = (res >> 16) & 0xff;
        gDest = (g >> 8) & 0xff;
        bDest = res & 0xff;
    }

    inline void argbBlend(uint32 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest) const {
        // Original logic has uint32 src and dst colors as ARGB8888
        // ++src_alpha;
        // uint32 dst_alpha = geta32(dst);
        // if (dst_alpha)
        //     ++dst_alpha;
        // uint32 dst_g = (dst & 0x00FF00) * dst_alpha / 256;
        // dst = (dst & 0xFF00FF) * dst_alpha / 256;
        // dst_g = (((src & 0x00FF00) - (dst_g & 0x00FF00)) * src_alpha / 256 + dst_g) & 0x00FF00;
        // dst = (((src & 0xFF00FF) - (dst & 0xFF00FF)) * src_alpha / 256 + dst) & 0xFF00FF;
        // dst_alpha = 256 - (256 - src_alpha) * (256 - dst_alpha) / 256;
        // src_alpha = /* 256 * 256 == */ 0x10000 / dst_alpha;
        // dst_g = (dst_g * src_alpha / 256) & 0x00FF00;
        // dst = (dst * src_alpha / 256) & 0xFF00FF;
        // return dst | dst_g | (--dst_alpha << 24);
        double sAlpha = (double)(aSrc & 0xff) / 255.0;
        double dAlpha = (double)aDest / 255.0;
        dAlpha *= (1.0 - sAlpha);
        rDest = static_cast<uint8>((rSrc * sAlpha + rDest * dAlpha) / (sAlpha + dAlpha));
        gDest = static_cast<uint8>((gSrc * sAlpha + gDest * dAlpha) / (sAlpha + dAlpha));
        bDest = static_cast<uint8>((bSrc * sAlpha + bDest * dAlpha) / (sAlpha + dAlpha));
        aDest = static_cast<uint8>(255. * (sAlpha + dAlpha));
    }

    // kRgbToRgbBlender
    inline void blendRgbToRgb(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Default mode for set_trans_blender
        rgbBlend(rSrc, gSrc, bSrc, rDest, gDest, bDest, alpha);
        // Original doesn't set alpha (so it is 0), but the function is not meant to be used
        // on bitmap with transparency. Should we set alpha to 0xff?
        aDest = 0;
    }

    // kAlphaPreservedBlenderMode
    inline void blendPreserveAlpha(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Original blender function: _myblender_alpha_trans24
        // Like blendRgbToRgb, but result as the same alpha as destColor
        rgbBlend(rSrc, gSrc, bSrc, rDest, gDest, bDest, alpha);
        // Preserve value in aDest
    }

    // kArgbToArgbBlender
    inline void blendArgbToArgb(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Original blender functions: _argb2argb_blender
        if (alpha == 0)
            alpha = aSrc;
        else
            alpha = aSrc * ((alpha & 0xff) + 1) / 256;
        if (alpha != 0)
            argbBlend(alpha, rSrc, gSrc, bSrc, aDest, rDest, gDest, bDest);
    }

    // kRgbToArgbBlender
    inline void blendRgbToArgb(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Original blender function: _rgb2argb_blenders
        if (alpha == 0 || alpha == 0xff) {
            aDest = 0xff;
            rDest = rSrc;
            gDest = gSrc;
            bDest = bSrc;
        } else
            argbBlend(alpha, rSrc, gSrc, bSrc, aDest, rDest, gDest, bDest);
    }

    // kArgbToRgbBlender
    inline void blendArgbToRgb(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Original blender function: _argb2rgb_blender
        if (alpha == 0)
            alpha = aSrc;
        else
            alpha = aSrc * ((alpha & 0xff) + 1) / 256;
        rgbBlend(rSrc, gSrc, bSrc, rDest, gDest, bDest, alpha);
        // Original doesn't set alpha (so it is 0), but the function is not meant to be used
        // on bitmap with transparency. Should we set alpha to 0xff?
        aDest = 0;
    }

    // kOpaqueBlenderMode
    inline void blendOpaque(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Original blender function: _opaque_alpha_blender
        aDest = 0xff;
        rDest = rSrc;
        gDest = gSrc;
        bDest = bSrc;
    }

    // kSourceAlphaBlender
    inline void blendSourceAlpha(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Used after set_alpha_blender
        // Uses alpha from source. Result is fully opaque
        rgbBlend(rSrc, gSrc, bSrc, rDest, gDest, bDest, aSrc);
        // Original doesn't set alpha (so it is 0), but the function is not meant to be used
        // on bitmap with transparency. Should we set alpha to 0xff?
        aDest = 0;
    }

    // kAdditiveBlenderMode
    inline void blendAdditiveAlpha(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha) const {
        // Original blender function: _additive_alpha_copysrc_blender
        rDest = rSrc;
        gDest = gSrc;
        bDest = bSrc;
        uint32 a = (uint32)aSrc + (uint32)aDest;
        if (a > 0xff)
            aDest = 0xff;
        else
            aDest = static_cast<uint8>(a);
    }

    // kTintBlenderMode and kTintLightBlenderMode
    void blendTintSprite(uint8 aSrc, uint8 rSrc, uint8 gSrc, uint8 bSrc, uint8 &aDest, uint8 &rDest, uint8 &gDest, uint8 &bDest, uint32 alpha, bool light) const;

    friend class DrawInnerImpl_AVX2;
    friend class DrawInnerImpl_SSE2;
    friend class DrawInnerImpl_NEON;

    constexpr static int SCALE_THRESHOLD_BITS = 8;
    constexpr static int SCALE_THRESHOLD = 1 << SCALE_THRESHOLD_BITS;
    struct DrawInnerArgs {
        const bool useTint, horizFlip, vertFlip, skipTrans;
        bool sameFormat, shouldDraw;
        int xStart, yStart, srcAlpha, tintRed, tintGreen, tintBlue, scaleX, scaleY;
        uint32 transColor, alphaMask;
        PALETTE palette;

        BlenderMode blenderMode;
        Common::Rect dstRect, srcArea;

        BITMAP &dstBitmap;
        const ::Graphics::ManagedSurface &src;
        ::Graphics::Surface destArea;

        DrawInnerArgs(BITMAP *dstBitmap, const BITMAP *srcBitmap,
                      const Common::Rect &srcRect, const Common::Rect &dstRect,
                      bool skipTrans, int srcAlpha, bool horizFlip,
                      bool vertFlip, int tintRed, int tintGreen, int tintBlue,
                      bool doScale);
    };

    template<bool Scale>
    void drawGeneric(DrawInnerArgs &args);
#ifdef SCUMMVM_NEON
    template<bool Scale>
    void drawNEON(DrawInnerArgs &args);
#endif
#ifdef SCUMMVM_SSE2
    template<bool Scale>
    void drawSSE2(DrawInnerArgs &args);
#endif
#ifdef SCUMMVM_AVX2
    template<bool Scale>
    void drawAVX2(DrawInnerArgs &args);
#endif
    template<int DestBytesPerPixel, int SrcBytesPerPixel, bool Scale>
    void drawInnerGeneric(DrawInnerArgs &args);
    
    inline uint32 getColor(const byte *data, byte bpp) const {
        switch (bpp) {
        case 1:
            return *data;
        case 2:
            return *(const uint16 *)data;
        case 4:
            return *(const uint32 *)data;
        default:
            error("Unsupported format in BITMAP::getColor");
        }
    }
};

class Surface : public Graphics::ManagedSurface, public BITMAP {
public:
    Surface(int width, int height, const Graphics::PixelFormat &pixelFormat) :
        Graphics::ManagedSurface(width, height, pixelFormat), BITMAP(this) {
        // Allegro uses 255, 0, 255 RGB as the transparent color
        if (pixelFormat.bytesPerPixel == 2 || pixelFormat.bytesPerPixel == 4)
            setTransparentColor(pixelFormat.RGBToColor(255, 0, 255));
    }
    Surface(Graphics::ManagedSurface &surf, const Common::Rect &bounds) :
        Graphics::ManagedSurface(surf, bounds), BITMAP(this) {
        // Allegro uses 255, 0, 255 RGB as the transparent color
        if (surf.format.bytesPerPixel == 2 || surf.format.bytesPerPixel == 4)
            setTransparentColor(surf.format.RGBToColor(255, 0, 255));
    }
    ~Surface() override {
    }
};

BITMAP *create_bitmap(int width, int height);
BITMAP *create_bitmap_ex(int color_depth, int width, int height);
BITMAP *create_sub_bitmap(BITMAP *parent, int x, int y, int width, int height);
BITMAP *create_video_bitmap(int width, int height);
BITMAP *create_system_bitmap(int width, int height);
void destroy_bitmap(BITMAP *bitmap);

} // namespace AGS3

#endif