Use the input resolution in the blur instead of hard-coding 1280x720. Also fix mipmap...
authorSteinar H. Gunderson <sgunderson@bigfoot.com>
Tue, 9 Oct 2012 10:16:30 +0000 (12:16 +0200)
committerSteinar H. Gunderson <sgunderson@bigfoot.com>
Tue, 9 Oct 2012 10:16:30 +0000 (12:16 +0200)
blur_effect.cpp
blur_effect.h

index f5d9927..b48dc95 100644 (file)
 #define NUM_TAPS 16
        
 BlurEffect::BlurEffect()
-       : radius(3.0f)
+       : radius(3.0f),
+         input_width(1280),
+         input_height(720)
 {
-       hpass = new SingleBlurPassEffect();
+       // The first blur pass will forward resolution information to us.
+       hpass = new SingleBlurPassEffect(this);
        hpass->set_int("direction", SingleBlurPassEffect::HORIZONTAL);
-       vpass = new SingleBlurPassEffect();
+       vpass = new SingleBlurPassEffect(NULL);
        vpass->set_int("direction", SingleBlurPassEffect::VERTICAL);
 
        update_radius();
@@ -28,6 +31,18 @@ void BlurEffect::rewrite_graph(EffectChain *graph, Node *self)
        graph->replace_receiver(self, hpass_node);
        graph->replace_sender(self, vpass_node);
        self->disabled = true;
+} 
+
+// We get this information forwarded from the first blur pass,
+// since we are not part of the chain ourselves.
+void BlurEffect::inform_input_size(unsigned input_num, unsigned width, unsigned height)
+{
+       assert(input_num == 0);
+       assert(width != 0);
+       assert(height != 0);
+       input_width = width;
+       input_height = height;
+       update_radius();
 }
                
 void BlurEffect::update_radius()
@@ -35,23 +50,24 @@ void BlurEffect::update_radius()
        // We only have 16 taps to work with on each side, and we want that to
        // reach out to about 2.5*sigma. Bump up the mipmap levels (giving us
        // box blurs) until we have what we need.
-       //
-       // TODO: Consider the actual width and height (they influence mipmap
-       // sizes subtly).
-       unsigned base_mipmap_level = 0;
+       unsigned mipmap_width = input_width, mipmap_height = input_height;
        float adjusted_radius = radius;
-       while (adjusted_radius * 1.5f > NUM_TAPS / 2) {
-               ++base_mipmap_level;
-               adjusted_radius /= 2.0f;
+       while ((mipmap_width > 1 || mipmap_height > 1) && adjusted_radius * 1.5f > NUM_TAPS / 2) {
+               // Find the next mipmap size (round down, minimum 1 pixel).
+               mipmap_width = std::max(mipmap_width / 2, 1u);
+               mipmap_height = std::max(mipmap_height / 2, 1u);
+
+               // Approximate when mipmap sizes are odd, but good enough.
+               adjusted_radius = radius * float(mipmap_width) / float(input_width);
        }
        
        bool ok = hpass->set_float("radius", adjusted_radius);
-       ok |= hpass->set_int("width", 1280 / (1 << base_mipmap_level));  // FIXME
-       ok |= hpass->set_int("height", 720 / (1 << base_mipmap_level));  // FIXME
+       ok |= hpass->set_int("width", mipmap_width);
+       ok |= hpass->set_int("height", mipmap_height);
 
        ok |= vpass->set_float("radius", adjusted_radius);
-       ok |= vpass->set_int("width", 1280 / (1 << base_mipmap_level));  // FIXME
-       ok |= vpass->set_int("height", 720 / (1 << base_mipmap_level));  // FIXME
+       ok |= vpass->set_int("width", mipmap_width);
+       ok |= vpass->set_int("height", mipmap_height);
 
        assert(ok);
 }
@@ -65,8 +81,9 @@ bool BlurEffect::set_float(const std::string &key, float value) {
        return false;
 }
 
-SingleBlurPassEffect::SingleBlurPassEffect()
-       : radius(3.0f),
+SingleBlurPassEffect::SingleBlurPassEffect(BlurEffect *parent)
+       : parent(parent),
+         radius(3.0f),
          direction(HORIZONTAL),
          width(1280),
          height(720)
index 2aada42..7f92074 100644 (file)
@@ -25,6 +25,8 @@ public:
        virtual bool needs_mipmaps() const { return true; }
        virtual bool needs_srgb_primaries() const { return false; }
 
+       virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
+
        virtual std::string output_fragment_shader() {
                assert(false);
        }
@@ -40,11 +42,14 @@ private:
        
        float radius;
        SingleBlurPassEffect *hpass, *vpass;
+       unsigned input_width, input_height;
 };
 
 class SingleBlurPassEffect : public Effect {
 public:
-       SingleBlurPassEffect();
+       // If parent is non-NULL, calls to inform_input_size will be forwarded
+       // so that it can make reasonable decisions for both blur passes.
+       SingleBlurPassEffect(BlurEffect *parent);
        virtual std::string effect_type_id() const { return "SingleBlurPassEffect"; }
 
        std::string output_fragment_shader();
@@ -53,6 +58,11 @@ public:
        virtual bool needs_mipmaps() const { return true; }
        virtual bool needs_srgb_primaries() const { return false; }
 
+       virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {
+               if (parent != NULL) {
+                       parent->inform_input_size(input_num, width, height);
+               }
+       }
        virtual bool changes_output_size() const { return true; }
 
        virtual void get_output_size(unsigned *width, unsigned *height) const {
@@ -66,6 +76,7 @@ public:
        enum Direction { HORIZONTAL = 0, VERTICAL = 1 };
 
 private:
+       BlurEffect *parent;
        float radius;
        Direction direction;
        int width, height;