shithub: brokentoys

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image/convolution: more fixes

--- a/image/convolution.c

+++ b/image/convolution.c

@@ -88,16 +88,15 @@

 static void

 normalize(double *k, int dim)

 {

-	double avg;

+	double denom;

 	int i, j;

-	avg = coeffsum(k, dim);

-	avg /= dim*dim;

-	if(avg == 0)

-		avg = 1;

+	denom = coeffsum(k, dim);

+	if(denom == 0)

+		return;

 	for(j = 0; j < dim; j++)

 	for(i = 0; i < dim; i++)

-		k[j*dim+i] /= avg;

+		k[j*dim+i] /= denom;

 }

 static double *

@@ -130,17 +129,14 @@

 convolve(double *d, double *s, int dim)

 {

 	int i, j;

-	double denom, r;

+	double r;

-	denom = coeffsum(s, dim);

-	denom = denom == 0? 1: 1/denom;

-

 	modulate(d, s, dim);

 	r = 0;

 	for(j = 0; j < dim; j++)

 	for(i = 0; i < dim; i++)

 		r += d[j*dim+i];

-	return fabs(r*denom);

+	return r;

 }

 static uchar

@@ -158,7 +154,7 @@

 	double **im;

 	Rectangle imr;

 	Point imc, p, cp;

-	double c;

+	double denom, c;

 	int i;

 	im = malloc(d->nchan*sizeof(double*));

@@ -173,6 +169,9 @@

 	imr = Rect(0,0,dim,dim);

 	imc = Pt(dim/2, dim/2);

+	denom = coeffsum(k, dim);

+	denom = denom == 0? 1: 1/denom;

+

 	for(p.y = s->r.min.y; p.y < s->r.max.y; p.y++)

 	for(p.x = s->r.min.x; p.x < s->r.max.x; p.x++){

 		for(cp.y = imr.min.y; cp.y < imr.max.y; cp.y++)

@@ -181,7 +180,7 @@

 				im[i][cp.y*dim + cp.x] = sample(s, addpt(p, subpt(cp, imc)), i);

 		}

 		for(i = 0; i < d->nchan; i++){

-			c = convolve(im[i], k, dim);

+			c = fabs(convolve(im[i], k, dim) * denom);

 			if(saturate)

 				c = clamp(c, 0, 0xFF);

 			*(byteaddr(d, p) + i) = c;

-- 

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