#include <assert.h>
#include "blur_effect.h"
+#include "effect_chain.h"
#include "util.h"
#include "opengl.h"
#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();
}
-void BlurEffect::add_self_to_effect_chain(EffectChain *chain, const std::vector<Effect *> &inputs)
+void BlurEffect::rewrite_graph(EffectChain *graph, Node *self)
{
- assert(inputs.size() == 1);
- hpass->add_self_to_effect_chain(chain, inputs);
-
- std::vector<Effect *> vpass_inputs;
- vpass_inputs.push_back(hpass);
- vpass->add_self_to_effect_chain(chain, vpass_inputs);
+ Node *hpass_node = graph->add_node(hpass);
+ Node *vpass_node = graph->add_node(vpass);
+ graph->connect_nodes(hpass_node, vpass_node);
+ 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()
// 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);
}
return false;
}
-SingleBlurPassEffect::SingleBlurPassEffect()
- : radius(3.0f),
+SingleBlurPassEffect::SingleBlurPassEffect(BlurEffect *parent)
+ : parent(parent),
+ radius(3.0f),
direction(HORIZONTAL),
width(1280),
height(720)
} else {
float sum = 0.0f;
for (unsigned i = 0; i < NUM_TAPS + 1; ++i) {
- float z = i / radius;
-
// Gaussian blur is a common, but maybe not the prettiest choice;
// it can feel a bit too blurry in the fine detail and too little
// long-tail. This is a simple logistic distribution, which has
// a narrower peak but longer tails.
+ //
+ // We interpret the radius as sigma, similar to Gaussian blur.
+ // Wikipedia says that sigma² = pi² s² / 3, which yields:
+ const float s = (sqrt(3.0) / M_PI) * radius;
+ float z = i / (2.0 * s);
+
weight[i] = 1.0f / (cosh(z) * cosh(z));
if (i == 0) {