vo_opengl: generalize --scale-clamp etc.

This can help fight ringing without completely killing it, thus
providing a middle-ground between ringing and aliasing.

4 files changed, 5 insertions, 5 deletions

diff --git a/video/out/filter_kernels.c b/video/out/filter_kernels.c
index 09f85af5f4..6c10eb30b5 100644
--- a/video/out/filter_kernels.c
+++ b/video/out/filter_kernels.c
@@ -117,8 +117,8 @@ static double sample_filter(struct filter_kernel *filter, double x)
 {
     // The window is always stretched to the entire kernel
     double w = sample_window(&filter->w, x / filter->f.radius * filter->w.radius);
-    double k = sample_window(&filter->f, x);
-    return filter->clamp ? fmax(0.0, fmin(1.0, w * k)) : w * k;
+    double k = w * sample_window(&filter->f, x);
+    return k < 0 ? (1 - filter->clamp) * k : k;
 }
 
 // Calculate the 1D filtering kernel for N sample points.
diff --git a/video/out/filter_kernels.h b/video/out/filter_kernels.h
index c9a89f6847..ac9b7fd39a 100644
--- a/video/out/filter_kernels.h
+++ b/video/out/filter_kernels.h
@@ -28,7 +28,7 @@ struct filter_window {
 struct filter_kernel {
     struct filter_window f; // the kernel itself
     struct filter_window w; // window storage
-    bool clamp; // clamp to the range [0-1]
+    double clamp; // clamping factor, affects negative weights
     double value_cutoff; // discard all contributions below this value (polar)
     // Constant values
     const char *window; // default window
diff --git a/video/out/opengl/video.c b/video/out/opengl/video.c
index 8f65b555c8..50e70ce08f 100644
--- a/video/out/opengl/video.c
+++ b/video/out/opengl/video.c
@@ -333,7 +333,7 @@ static int validate_window_opt(struct mp_log *log, const m_option_t *opt,
     OPT_FLOAT(n"-wparam", scaler[i].window.params[0], 0),                  \
     OPT_FLOAT(n"-wblur",  scaler[i].window.blur, 0),                       \
     OPT_FLOATRANGE(n"-wtaper", scaler[i].window.taper, 0, 0.0, 1.0),       \
-    OPT_FLAG(n"-clamp",   scaler[i].clamp, 0),                             \
+    OPT_FLOATRANGE(n"-clamp", scaler[i].clamp, 0, 0.0, 1.0),               \
     OPT_FLOATRANGE(n"-radius",    scaler[i].radius, 0, 0.5, 16.0),         \
     OPT_FLOATRANGE(n"-antiring",  scaler[i].antiring, 0, 0.0, 1.0),        \
     OPT_STRING_VALIDATE(n"-window", scaler[i].window.name, 0, validate_window_opt)
diff --git a/video/out/opengl/video.h b/video/out/opengl/video.h
index b4f91b802f..09083da41b 100644
--- a/video/out/opengl/video.h
+++ b/video/out/opengl/video.h
@@ -44,7 +44,7 @@ struct scaler_config {
     float radius;
     float antiring;
     float cutoff;
-    int clamp;
+    float clamp;
 };
 
 struct scaler {