2 files changed, 18 insertions, 12 deletions

diff --git a/src/libs/puddle/puddle.c b/src/libs/puddle/puddle.c
index e5c0dd4..c6833f7 100644
--- a/src/libs/puddle/puddle.c
+++ b/src/libs/puddle/puddle.c
@@ -106,9 +106,9 @@ static inline float lerp(float a, float b, float t)
 
 /* Sample the supplied puddle field at the specified coordinate.
  *
- * The puddle field is treated as a unit square mapped to the specified
- * dimensions @ create time.  the sampled value is linearly interpolated from
- * the data.
+ * The puddle field is treated as an unsigned unit square mapped to the
+ * specified dimensions @ create time.  the sampled value is linearly
+ * interpolated from the data. (coordinates range 0..1)
  */
 float puddle_sample(const puddle_t *puddle, const v2f_t *coordinate)
 {
@@ -118,8 +118,8 @@ float puddle_sample(const puddle_t *puddle, const v2f_t *coordinate)
 	assert(puddle);
 	assert(coordinate);
 
-	x = .5f + (coordinate->x * .5f + .5f) * (puddle->w - 2);
-	y = .5f + (coordinate->y * .5f + .5f) * (puddle->h - 2);
+	x = .5f + coordinate->x * (puddle->w - 2);
+	y = .5f + coordinate->y * (puddle->h - 2);
 
 	x0 = floorf(x);
 	y0 = floorf(y);
@@ -130,7 +130,10 @@ float puddle_sample(const puddle_t *puddle, const v2f_t *coordinate)
 	tx = x - (float)x0;
 	ty = y - (float)y0;
 
-	return lerp(lerp(puddle->a[y0 * puddle->w + x0], puddle->a[y0 * puddle->w + x1], tx),
-		    lerp(puddle->a[y1 * puddle->w + x0], puddle->a[y1 * puddle->w + x1], tx),
+	y0 *= puddle->w;
+	y1 *= puddle->w;
+
+	return lerp(lerp(puddle->a[y0 + x0], puddle->a[y0 + x1], tx),
+		    lerp(puddle->a[y1 + x0], puddle->a[y1 + x1], tx),
 		    ty);
 }
diff --git a/src/modules/drizzle/drizzle.c b/src/modules/drizzle/drizzle.c
index bc04456..f546cea 100644
--- a/src/modules/drizzle/drizzle.c
+++ b/src/modules/drizzle/drizzle.c
@@ -127,24 +127,27 @@ static void drizzle_prepare_frame(void *context, unsigned ticks, unsigned n_cpus
 static void drizzle_render_fragment(void *context, unsigned ticks, unsigned cpu, fb_fragment_t *fragment)
 {
 	drizzle_context_t	*ctxt = context;
-	float			xf = 2.f / (float)fragment->frame_width;
-	float			yf = 2.f / (float)fragment->frame_height;
+	float			xf = 1.f / (float)fragment->frame_width;
+	float			yf = 1.f / (float)fragment->frame_height;
 	v2f_t			coord;
 
+	coord.y = yf * (float)fragment->y;
 	for (int y = fragment->y; y < fragment->y + fragment->height; y++) {
-		coord.y = yf * (float)y - 1.f;
 
+		coord.x = xf * (float)fragment->x;
 		for (int x = fragment->x; x < fragment->x + fragment->width; x++) {
 			v3f_t		color = {};
 			uint32_t	pixel;
 
-			coord.x = xf * (float)x - 1.f;
-
 			color.z = puddle_sample(ctxt->puddle, &coord);
 
 			pixel = color_to_uint32(color);
 			fb_fragment_put_pixel_unchecked(fragment, x, y, pixel);
+
+			coord.x += xf;
 		}
+
+		coord.y += yf;
 	}
 }