--- ray/src/gen/gensurf.c	1992/01/30 14:11:39	2.2
+++ ray/src/gen/gensurf.c	1994/04/12 15:16:15	2.5
@@ -165,7 +165,9 @@ int  pointsize;
 	register FLOAT  *dp;
 
 	datarec.flags = HASBORDER;		/* assume border values */
-	size = (m+1)*(n+1)*pointsize;
+	datarec.m = m+1;
+	datarec.n = n+1;
+	size = datarec.m*datarec.n*pointsize;
 	if (pointsize == 3)
 		datarec.flags |= TRIPLETS;
 	dp = (FLOAT *)malloc(size*sizeof(FLOAT));
@@ -196,9 +198,12 @@ int  pointsize;
 		if (dp != NULL)
 			datarec.data = dp;
 		datarec.flags &= ~HASBORDER;
+		datarec.m = m;
+		datarec.n = n;
 		size = 0;
 	}
-	if (size || fgetword(word, sizeof(word), fp) != NULL) {
+	if (datarec.m < 2 || datarec.n < 2 || size != 0 ||
+			fgetword(word, sizeof(word), fp) != NULL) {
 		fputs(file, stderr);
 		fputs(": bad number of data points\n", stderr);
 		exit(1);
@@ -218,11 +223,11 @@ char  *nam;
 						/* compute coordinates */
 	u = argument(1); v = argument(2);
 	if (datarec.flags & HASBORDER) {
-		i = u *= datarec.m;
-		j = v *= datarec.n;
+		i = u *= datarec.m-1;
+		j = v *= datarec.n-1;
 	} else {
-		i = u = u*(datarec.m+1) - .5;
-		j = v = v*(datarec.n+1) - .5;
+		i = u = u*datarec.m - .5;
+		j = v = v*datarec.n - .5;
 	}
 	if (i < 0) i = 0;
 	else if (i > datarec.m-2) i = datarec.m-2;
@@ -230,18 +235,18 @@ char  *nam;
 	else if (j > datarec.n-2) j = datarec.n-2;
 						/* compute value */
 	if (datarec.flags & TRIPLETS) {
-		dp = datarec.data + 3*(j*datarec.n + i);
-		if (nam == YNAME)
-			dp++;
-		else if (nam == ZNAME)
+		dp = datarec.data + 3*(j*datarec.m + i);
+		if (nam == ZNAME)
 			dp += 2;
+		else if (nam == YNAME)
+			dp++;
 		d00 = dp[0]; d01 = dp[3];
-		dp += 3*datarec.n;
+		dp += 3*datarec.m;
 		d10 = dp[0]; d11 = dp[3];
 	} else {
-		dp = datarec.data + j*datarec.n + i;
+		dp = datarec.data + j*datarec.m + i;
 		d00 = dp[0]; d01 = dp[1];
-		dp += datarec.n;
+		dp += datarec.m;
 		d10 = dp[0]; d11 = dp[1];
 	}
 						/* bilinear interpolation */
@@ -370,7 +375,6 @@ register POINT  *r0, *r1, *r2;
 int  siz;
 {
 	FVECT  v1, v2;
-	register int  i;
 
 	if (!smooth)			/* not needed if no smoothing */
 		return;
@@ -425,7 +429,7 @@ POINT  *p0, *p1, *p2, *p3;
 	eqnmat[3][2] = p3->p[v];
 	eqnmat[3][3] = 1.0;
 					/* invert matrix (solve system) */
-	if (!invmat(eqnmat, eqnmat))
+	if (!invmat4(eqnmat, eqnmat))
 		return(-1);			/* no solution */
 					/* compute result matrix */
 	for (j = 0; j < 4; j++)
@@ -441,64 +445,6 @@ POINT  *p0, *p1, *p2, *p3;
 }
 
 
-/*
- * invmat - computes the inverse of mat into inverse.  Returns 1
- * if there exists an inverse, 0 otherwise.  It uses Gaussian Elimination
- * method.
- */
-
-invmat(inverse,mat)
-MAT4  inverse, mat;
-{
-#define SWAP(a,b,t) (t=a,a=b,b=t)
-
-	MAT4  m4tmp;
-	register int i,j,k;
-	register double temp;
-
-	copymat4(m4tmp, mat);
-					/* set inverse to identity */
-	for (i = 0; i < 4; i++)
-		for (j = 0; j < 4; j++)
-			inverse[i][j] = i==j ? 1.0 : 0.0;
-
-	for(i = 0; i < 4; i++) {
-		/* Look for row with largest pivot and swap rows */
-		temp = FTINY; j = -1;
-		for(k = i; k < 4; k++)
-			if(ABS(m4tmp[k][i]) > temp) {
-				temp = ABS(m4tmp[k][i]);
-				j = k;
-				}
-		if(j == -1)	/* No replacing row -> no inverse */
-			return(0);
-		if (j != i)
-			for(k = 0; k < 4; k++) {
-				SWAP(m4tmp[i][k],m4tmp[j][k],temp);
-				SWAP(inverse[i][k],inverse[j][k],temp);
-				}
-
-		temp = m4tmp[i][i];
-		for(k = 0; k < 4; k++) {
-			m4tmp[i][k] /= temp;
-			inverse[i][k] /= temp;
-			}
-		for(j = 0; j < 4; j++) {
-			if(j != i) {
-				temp = m4tmp[j][i];
-				for(k = 0; k < 4; k++) {
-					m4tmp[j][k] -= m4tmp[i][k]*temp;
-					inverse[j][k] -= inverse[i][k]*temp;
-					}
-				}
-			}
-		}
-	return(1);
-
-#undef SWAP
-}
-
-
 eputs(msg)
 char  *msg;
 {
@@ -514,6 +460,7 @@ char  *msg;
 
 
 quit(code)
+int  code;
 {
 	exit(code);
 }