/*
 * Copyright 2011, Blender Foundation.
 *
 * 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 2
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Contributor: 
 *		Jeroen Bakker 
 *		Monique Dewanchand
 */

#include "COM_GlareStreaksOperation.h"
#include "BLI_math.h"

void GlareStreaksOperation::generateGlare(float *data, MemoryBuffer *inputTile, NodeGlare *settings) {
	int x, y, n;
	unsigned int nump=0;
	float c1[4], c2[4], c3[4], c4[4];
	float a, ang = DEG2RADF(360.0f)/(float)settings->angle;
	
	int size = inputTile->getWidth()*inputTile->getHeight();
	int size4 = size*4;

	
	MemoryBuffer* tsrc = inputTile->duplicate();
	MemoryBuffer* tdst = new MemoryBuffer(NULL, inputTile->getRect());
	tdst->clear();
	memset(data, 0, size4*sizeof(float));
	
	for (a=0.f; a<DEG2RADF(360.0f); a+=ang) {
		const float an = a + settings->angle_ofs;
		const float vx = cos((double)an), vy = sin((double)an);
		for (n=0; n<settings->iter; ++n) {
			const float p4 = pow(4.0, (double)n);
			const float vxp = vx*p4, vyp = vy*p4;
			const float wt = pow((double)settings->fade, (double)p4);
			const float cmo = 1.f - (float)pow((double)settings->colmod, (double)n+1);	// colormodulation amount relative to current pass
			float* tdstcol = tdst->getBuffer();
			for (y=0; y<tsrc->getHeight(); ++y) {
				for (x=0; x<tsrc->getWidth(); ++x, tdstcol+=4) {
					// first pass no offset, always same for every pass, exact copy,
					// otherwise results in uneven brightness, only need once
					if (n==0) tsrc->read(c1, x, y); else c1[0]=c1[1]=c1[2]=0;
					tsrc->readCubic(c2, x + vxp, y + vyp);
					tsrc->readCubic(c3, x + vxp*2.f, y + vyp*2.f);
					tsrc->readCubic(c4, x + vxp*3.f, y + vyp*3.f);
					// modulate color to look vaguely similar to a color spectrum
					c2[1] *= cmo;
					c2[2] *= cmo;

					c3[0] *= cmo;
					c3[1] *= cmo;
					
					c4[0] *= cmo;
					c4[2] *= cmo;

					tdstcol[0] = 0.5f*(tdstcol[0] + c1[0] + wt*(c2[0] + wt*(c3[0] + wt*c4[0])));
					tdstcol[1] = 0.5f*(tdstcol[1] + c1[1] + wt*(c2[1] + wt*(c3[1] + wt*c4[1])));
					tdstcol[2] = 0.5f*(tdstcol[2] + c1[2] + wt*(c2[2] + wt*(c3[2] + wt*c4[2])));
					tdstcol[3] = 1.0f;
				}
			}
			memcpy(tsrc->getBuffer(), tdst->getBuffer(), sizeof(float)*size4);
		}

//		addImage(sbuf, tsrc, 1.f/(float)(6 - ndg->iter)); // add result to data @todo
		float* sourcebuffer = tsrc->getBuffer();
		float factor = 1.f/(float)(6 - settings->iter);
		for (int i = 0 ; i < size4; i ++) {
			data[i] += sourcebuffer[i] * factor;
		}
		for (int i = 0 ; i < size; i ++) {
			data[i*4+3] = 1.0f;
		}
		
		tdst->clear();
		memcpy(tsrc->getBuffer(), inputTile->getBuffer(), sizeof(float)*size4);
		nump++;
	}
	
	delete tsrc;
	delete tdst;
}