Keskustelu: Koodit: C: Nopea blur-efekti

void imageblur(SDL_Surface *screen, float nopa = 0.5){
	// Fast blur by T.M. - www.HC-Codes.net
	int lev = screen->w;
	int kor = screen->h;
	Uint8 *mpos = (Uint8 *)(screen->pixels);
	Uint8 *p;
	float r, g, b;
	float opa = 1-nopa;
	int x, y;
	int lev4 = lev*4;
	int leve = lev-1;
	int kore = kor-1;
	// Ei turhaan yritetä blurrata jos tulos ei eroa alkuperäisestä:
	if(nopa > 0){
		p = mpos;
		for(y = 0; y < kor; y++){
			// Vasemmalta oikealle:
			r = p[0];
			g = p[1];
			b = p[2];
			for(x = 0; x < lev; x++){
				p[0] = (int)((r = p[0]*opa+r*nopa)+0.5);
				p[1] = (int)((g = p[1]*opa+g*nopa)+0.5);
				p[2] = (int)((b = p[2]*opa+b*nopa)+0.5);
				p+=4;
			}
			// Oikealta vasemmalle:
			p-=4;
			r = p[0];
			g = p[1];
			b = p[2];
			for(x = leve; x >= 0; x--){
				p[0] = (int)((r = p[0]*opa+r*nopa)+0.5);
				p[1] = (int)((g = p[1]*opa+g*nopa)+0.5);
				p[2] = (int)((b = p[2]*opa+b*nopa)+0.5);
				p-=4;
			}
			p+=lev4+4;
		}
		for(x = 0; x < lev; x++){
			// Ylhäältä alas:
			p = mpos+(x<<2);
			r = p[0];
			g = p[1];
			b = p[2];
			for(y = 0; y < kor; y++){
				p[0] = (int)((r = p[0]*opa+r*nopa)+0.5);
				p[1] = (int)((g = p[1]*opa+g*nopa)+0.5);
				p[2] = (int)((b = p[2]*opa+b*nopa)+0.5);
				p+=lev4;
			}
			// Alhaalta ylös:
			p-=lev4;
			r = p[0];
			g = p[1];
			b = p[2];
			for(y = kore; y >= 0; y--){
				p[0] = (int)((r = p[0]*opa+r*nopa)+0.5);
				p[1] = (int)((g = p[1]*opa+g*nopa)+0.5);
				p[2] = (int)((b = p[2]*opa+b*nopa)+0.5);
				p-=lev4;
			}
		}
	}
}