Aegisub/prs/prs_video_frame.cpp

// Copyright (c) 2005, Rodrigo Braz Monteiro
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// -----------------------------------------------------------------------------
//
// AEGISUB
//
// Website: http://aegisub.cellosoft.com
// Contact: mailto:zeratul@cellosoft.com
//


///////////
// Headers
#include "prs_video_frame.h"


//////////
// Macros
#ifndef MIN
#define MIN(a,b) ((a)<(b))?(a):(b)
#endif

#ifndef MAX
#define MAX(a,b) ((a)>(b))?(a):(b)
#endif

#ifndef MID
#define MID(a,b,c) MAX(a,MIN(b,c))
#endif


///////////////
// Constructor
PRSVideoFrame::PRSVideoFrame () {
	for (int i=0;i<4;i++) data[i] = 0;
	w = 0;
	h = 0;
	ownData = false;
	flipColors = false;
	flipVertical = false;
}


//////////////
// Destructor
PRSVideoFrame::~PRSVideoFrame () {
	if (ownData) {
		for (int i=0;i<4;i++) delete [] data[i];
	}
}


///////////////////////////////////
// Overlay frame on top of another
// This function could get some optimization/assembly love
// Also, perhaps using "(x+1) >> 8" instead of "x / 255" should be considered.
void PRSVideoFrame::Overlay(PRSVideoFrame *dstFrame,int x,int y,unsigned char alpha,unsigned char blend) {
	// TODO: Colorspace conversion, for now, the function assumes RGB32 on RGB32!

	// Get pointers
	const unsigned char *src;
	unsigned char *dst;

	// Flip?
	bool flipVer = flipVertical != dstFrame->flipVertical;
	bool flipCol = flipColors != dstFrame->flipColors;
	if (flipCol) y = dstFrame->h - h - y;

	// Get boundaries
	int srcBpp = 4;
	int dstBpp = 4;
	int srcRowLen = pitch;
	int dstRowLen = dstFrame->pitch;
	int dstStarty = MAX(0,y);
	int dstEndy = MIN(y+h,dstFrame->h);
	int height = dstEndy - dstStarty;
	int rowLen = MID(0,w,dstFrame->w - x);

	// Values
	unsigned char sc1,sc2,sc3,a,ia,aux;
	unsigned char dc1,dc2,dc3,da;

	// Draw each row
	for (int j=0;j<height;j++) {
		src = (const unsigned char *) data[0] + j*srcRowLen;
		dst = (unsigned char *) dstFrame->data[0] + x*dstBpp;
		if (flipCol) dst += (h-j-1+dstStarty)*dstRowLen;
		else dst += (j+dstStarty)*dstRowLen;

		// Draw the row
		for (int i=0;i<rowLen;i++) {
			// Read source
			sc1 = *src++;
			sc2 = *src++;
			sc3 = *src++;
			a = ((*src++) * alpha) / 255;
			ia = 255-a;

			// Swap colors
			if (flipCol) {
				aux = sc1;
				sc1 = sc3;
				sc3 = aux;
			}

			// Read destination
			dc1 = *(dst);
			dc2 = *(dst+1);
			dc3 = *(dst+2);
			da = *(dst+3);

			// Normal blend
			if (blend == 0) {
				*dst++ = (sc1*a + dc1*ia)/255;			// Why does this work without cast to int? It should overflow...
				*dst++ = (sc2*a + dc2*ia)/255;
				*dst++ = (sc3*a + dc3*ia)/255;
				*dst++ = 255-(ia*(255-da)/255);
			}

			// Add blend
			else if (blend == 1) {
				*dst++ = MIN(255,(int(sc1)*a + int(dc1))/255);
				*dst++ = MIN(255,(int(sc2)*a + int(dc2))/255);
				*dst++ = MIN(255,(int(sc3)*a + int(dc3))/255);
				*dst++ = 255-(ia*(255-da)/255);			// Is this correct?
			}

			// Subtract blend
			else if (blend == 2) {
				*dst++ = MAX(0,(int(dc1) - sc1*a)/255);
				*dst++ = MAX(0,(int(dc2) - sc2*a)/255);
				*dst++ = MAX(0,(int(dc3) - sc3*a)/255);
				*dst++ = 255-(ia*(255-da)/255);			// Is this correct?
			}

			// Inverse subtract blend
			else if (blend == 3) {
				*dst++ = MAX(0,(sc1*a - int(dc1))/255);
				*dst++ = MAX(0,(sc2*a - int(dc2))/255);
				*dst++ = MAX(0,(sc3*a - int(dc3))/255);
				*dst++ = 255-(ia*(255-da)/255);			// Is this correct?
			}

			// Multiply blend
			else if (blend == 4) {
				*dst++ = MIN(255,(int(sc1)*a * int(dc1) / 255)/255);
				*dst++ = MIN(255,(int(sc2)*a * int(dc2) / 255)/255);
				*dst++ = MIN(255,(int(sc3)*a * int(dc3) / 255)/255);
				*dst++ = 255-(ia*(255-da)/255);			// Is this correct?
			}
		}
	}
}


//////////////////
// Get frame size
int PRSVideoFrame::GetSize() {
	return sizeof(PRSVideoFrame) + pitch * h;
}


//////////////////////
// Cached constructor
PRSCachedFrame::PRSCachedFrame () {
	frame = 0;
	id = -1;
}


/////////////////////
// Cached destructor
PRSCachedFrame::~PRSCachedFrame() {
	delete frame;
	frame = 0;
}