X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=blur_effect.cpp;h=adffe089a6d452d5f06a2c9907710aa152ee1f6f;hp=e945295da641dd565c74b54684be93e158de0022;hb=f216b7bef5a968c89f6fc78e83cc26a91e504a8a;hpb=b5e3174594efe9a920621a68d3b28f5e44676d03

diff --git a/blur_effect.cpp b/blur_effect.cpp
index e945295..adffe08 100644
--- a/blur_effect.cpp
+++ b/blur_effect.cpp
@@ -1,24 +1,226 @@
-#define GL_GLEXT_PROTOTYPES 1
-
+#include <epoxy/gl.h>
+#include <assert.h>
 #include <math.h>
-#include <GL/gl.h>
-#include <GL/glext.h>
+#include <algorithm>
 
 #include "blur_effect.h"
+#include "effect_chain.h"
+#include "effect_util.h"
+#include "init.h"
 #include "util.h"
 
+using namespace std;
+
+namespace movit {
+	
 BlurEffect::BlurEffect()
-	: radius(0.3f)
+	: num_taps(16),
+	  radius(3.0f),
+	  input_width(1280),
+	  input_height(720)
 {
-	register_float("radius", (float *)&radius);
+	// The first blur pass will forward resolution information to us.
+	hpass = new SingleBlurPassEffect(this);
+	CHECK(hpass->set_int("direction", SingleBlurPassEffect::HORIZONTAL));
+	vpass = new SingleBlurPassEffect(NULL);
+	CHECK(vpass->set_int("direction", SingleBlurPassEffect::VERTICAL));
+
+	update_radius();
 }
 
-std::string BlurEffect::output_fragment_shader()
+void BlurEffect::rewrite_graph(EffectChain *graph, Node *self)
+{
+	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)
 {
-	return read_file("blur_effect.frag");
+	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.
+	unsigned mipmap_width = input_width, mipmap_height = input_height;
+	float adjusted_radius = radius;
+	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 = max(mipmap_width / 2, 1u);
+		mipmap_height = 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", mipmap_width);
+	ok |= hpass->set_int("height", mipmap_height);
+	ok |= hpass->set_int("virtual_width", mipmap_width);
+	ok |= hpass->set_int("virtual_height", mipmap_height);
+	ok |= hpass->set_int("num_taps", num_taps);
+
+	ok |= vpass->set_float("radius", adjusted_radius);
+	ok |= vpass->set_int("width", mipmap_width);
+	ok |= vpass->set_int("height", mipmap_height);
+	ok |= vpass->set_int("virtual_width", input_width);
+	ok |= vpass->set_int("virtual_height", input_height);
+	ok |= vpass->set_int("num_taps", num_taps);
+
+	assert(ok);
 }
 
-void BlurEffect::set_uniforms(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num)
+bool BlurEffect::set_float(const string &key, float value) {
+	if (key == "radius") {
+		radius = value;
+		update_radius();
+		return true;
+	}
+	return false;
+}
+
+bool BlurEffect::set_int(const string &key, int value) {
+	if (key == "num_taps") {
+		if (value < 2 || value % 2 != 0) {
+			return false;
+		}
+		num_taps = value;
+		update_radius();
+		return true;
+	}
+	return false;
+}
+
+SingleBlurPassEffect::SingleBlurPassEffect(BlurEffect *parent)
+	: parent(parent),
+	  num_taps(16),
+	  radius(3.0f),
+	  direction(HORIZONTAL),
+	  width(1280),
+	  height(720),
+	  uniform_samples(NULL)
 {
-	Effect::set_uniforms(glsl_program_num, prefix, sampler_num);
+	register_float("radius", &radius);
+	register_int("direction", (int *)&direction);
+	register_int("width", &width);
+	register_int("height", &height);
+	register_int("virtual_width", &virtual_width);
+	register_int("virtual_height", &virtual_height);
+	register_int("num_taps", &num_taps);
 }
+
+SingleBlurPassEffect::~SingleBlurPassEffect()
+{
+	delete[] uniform_samples;
+}
+
+string SingleBlurPassEffect::output_fragment_shader()
+{
+	char buf[256];
+	sprintf(buf, "#define DIRECTION_VERTICAL %d\n#define NUM_TAPS %d\n",
+		(direction == VERTICAL), num_taps);
+	uniform_samples = new float[2 * (num_taps / 2 + 1)];
+	register_uniform_vec2_array("samples", uniform_samples, num_taps / 2 + 1);
+	return buf + read_file("blur_effect.frag");
+}
+
+void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const string &prefix, unsigned *sampler_num)
+{
+	Effect::set_gl_state(glsl_program_num, prefix, sampler_num);
+
+	// Compute the weights; they will be symmetrical, so we only compute
+	// the right side.
+	float* weight = new float[num_taps + 1];
+	if (radius < 1e-3) {
+		weight[0] = 1.0f;
+		for (int i = 1; i < num_taps + 1; ++i) {
+			weight[i] = 0.0f;
+		}
+	} else {
+		float sum = 0.0f;
+		for (int i = 0; i < num_taps + 1; ++i) {
+			// 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) {
+				sum += weight[i];
+			} else {
+				sum += 2.0f * weight[i];
+			}
+		}
+		for (int i = 0; i < num_taps + 1; ++i) {
+			weight[i] /= sum;
+		}
+	}
+
+	// Since the GPU gives us bilinear sampling for free, we can get two
+	// samples for the price of one (for every but the center sample,
+	// in which case this trick doesn't buy us anything). Simply sample
+	// between the two pixel centers, and we can do with fewer weights.
+	// (This is right even in the vertical pass where we don't actually
+	// sample between the pixels, because we have linear interpolation
+	// there too.)
+	//
+	// We pack the parameters into a float4: The relative sample coordinates
+	// in (x,y), and the weight in z. w is unused.
+
+	// Center sample.
+	uniform_samples[2 * 0 + 0] = 0.0f;
+	uniform_samples[2 * 0 + 1] = weight[0];
+
+	int size;
+	if (direction == HORIZONTAL) {
+		size = width;
+	} else if (direction == VERTICAL) {
+		size = height;
+	} else {
+		assert(false);
+	}
+	float num_subtexels = size / movit_texel_subpixel_precision;
+	float inv_num_subtexels = movit_texel_subpixel_precision / size;
+
+	// All other samples.
+	for (int i = 1; i < num_taps / 2 + 1; ++i) {
+		unsigned base_pos = i * 2 - 1;
+		float w1 = weight[base_pos];
+		float w2 = weight[base_pos + 1];
+
+		float pos1 = base_pos / (float)size;
+		float pos2 = (base_pos + 1) / (float)size;
+		float pos, total_weight;
+		combine_two_samples(w1, w2, pos1, pos2, num_subtexels, inv_num_subtexels, &pos, &total_weight, NULL);
+
+		uniform_samples[2 * i + 0] = pos;
+		uniform_samples[2 * i + 1] = total_weight;
+	}
+
+	delete[] weight;
+}
+
+void SingleBlurPassEffect::clear_gl_state()
+{
+}
+
+}  // namespace movit