diff --git a/pipi/context.c b/pipi/context.c
index efe366c..4238747 100644
--- a/pipi/context.c
+++ b/pipi/context.c
@@ -778,7 +778,7 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
         pipi_image_t *tmp;
         char const *arg;
         va_list ap;
-        float freq, phase, theta, ampx, ampy;
+        float dw, dh, d = 0.0, a = 0.0;
         int ret;
 
         if(ctx->nimages < 1)
@@ -788,14 +788,12 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
         arg = va_arg(ap, char const *);
         va_end(ap);
 
-        ret = sscanf(arg, "%g,%g,%g,%gx%g",
-                     &freq, &phase, &theta, &ampx, &ampy);
-        if(ret < 5)
+        ret = sscanf(arg, "%gx%g+%gr%g", &dw, &dh, &d, &a);
+        if(ret < 2)
             return -1;
 
         tmp = ctx->images[ctx->nimages - 1];
-        ctx->images[ctx->nimages - 1] = pipi_wave(tmp, freq, phase,
-                                                  theta, ampx, ampy);
+        ctx->images[ctx->nimages - 1] = pipi_wave(tmp, dw, dh, d, a);
         pipi_free(tmp);
     }
     else
diff --git a/pipi/filter/wave.c b/pipi/filter/wave.c
index cb82876..416fc45 100644
--- a/pipi/filter/wave.c
+++ b/pipi/filter/wave.c
@@ -26,13 +26,15 @@
 #include "pipi.h"
 #include "pipi_internals.h"
 
-pipi_image_t *pipi_wave(pipi_image_t *src, double freq, double phase,
-                        double theta, double xamp, double yamp)
+#define BORDER 64
+
+pipi_image_t *pipi_wave(pipi_image_t *src, double dw, double dh,
+                        double d, double a)
 {
     pipi_image_t *dst;
     pipi_pixels_t *srcp, *dstp;
     float *srcdata, *dstdata;
-    double sint, cost;
+    double sina, cosa;
     int x, y, w, h, i, gray;
 
     w = src->w;
@@ -49,26 +51,29 @@ pipi_image_t *pipi_wave(pipi_image_t *src, double freq, double phase,
                 : pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
     dstdata = (float *)dstp->pixels;
 
-    sint = sin(theta);
-    cost = cos(theta);
+    sina = sin(a);
+    cosa = cos(a);
 
     for(y = 0; y < h; y++)
     {
         for(x = 0; x < w; x++)
         {
-            double t = cost * (x - w / 2) + sint * (y - h / 2);
-            double step = sin(t * freq + phase);
-            double dx = xamp;
-            double dy = yamp;
+            double angle = 2 * M_PI / dw * ((x - w / 2) * cosa
+                                             + (y - h / 2) * sina - d);
+            double displacement = dh * sin(angle);
+            double dx, dy;
             int x2, y2;
 
-            if(x < 32) dx = dx * x / 32;
-            if(x > w - 1 - 32) dx = dx * (w - 1 - x) / 32;
-            if(y < 32) dy = dy * y / 32;
-            if(y > h - 1 - 32) dy = dy * (h - 1 - y) / 32;
+            dx = -sina * displacement;
+            dy = cosa * displacement;
+
+            if(x < BORDER) dx = dx * x / BORDER;
+            if(x > w - 1 - BORDER) dx = dx * (w - 1 - x) / BORDER;
+            if(y < BORDER) dy = dy * y / BORDER;
+            if(y > h - 1 - BORDER) dy = dy * (h - 1 - y) / BORDER;
 
-            x2 = x + dx * step;
-            y2 = y + dy * step;
+            x2 = x + dx;
+            y2 = y + dy;
 
             /* Just in case... */
             if(x2 < 0) x2 = 0;
diff --git a/pipi/pipi.h b/pipi/pipi.h
index 0a8d627..9f7288b 100644
--- a/pipi/pipi.h
+++ b/pipi/pipi.h
@@ -198,7 +198,7 @@ __extern pipi_image_t *pipi_median_ext(pipi_image_t *, int, int);
 __extern pipi_image_t *pipi_dilate(pipi_image_t *);
 __extern pipi_image_t *pipi_erode(pipi_image_t *);
 __extern pipi_image_t *pipi_wave(pipi_image_t *, double, double,
-                                 double, double, double);
+                                 double, double);
 
 __extern pipi_image_t *pipi_order(pipi_image_t *);