X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=blur_effect.cpp;h=ec61aeab784f8a9f8b3574a29e48141162b6b2f7;hp=22e7d0ba781f40e4cd2ef385bb194005cf39fc70;hb=34f5f331bd3b643949ccbb0c3488af2823634d59;hpb=ab636361e865c389fe60584562372ec39ac4c511

diff --git a/blur_effect.cpp b/blur_effect.cpp
index 22e7d0b..ec61aea 100644
--- a/blur_effect.cpp
+++ b/blur_effect.cpp
@@ -2,41 +2,96 @@
 #include <assert.h>
 
 #include "blur_effect.h"
+#include "effect_chain.h"
 #include "util.h"
 #include "opengl.h"
 
 // Must match blur_effect.frag.
 #define NUM_TAPS 16
 	
-BlurEffect::BlurEffect() {
-	hpass = new SingleBlurPassEffect();
+BlurEffect::BlurEffect()
+	: radius(3.0f),
+	  input_width(1280),
+	  input_height(720)
+{
+	// 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) {
-	assert(inputs.size() == 1);
-	hpass->add_self_to_effect_chain(chain, inputs);
+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)
+{
+	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 = 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", mipmap_width);
+	ok |= hpass->set_int("height", mipmap_height);
 
-	std::vector<Effect *> vpass_inputs;
-	vpass_inputs.push_back(hpass);
-	vpass->add_self_to_effect_chain(chain, vpass_inputs);
+	ok |= vpass->set_float("radius", adjusted_radius);
+	ok |= vpass->set_int("width", mipmap_width);
+	ok |= vpass->set_int("height", mipmap_height);
+
+	assert(ok);
 }
 
 bool BlurEffect::set_float(const std::string &key, float value) {
-	if (!hpass->set_float(key, value)) {
-		return false;
+	if (key == "radius") {
+		radius = value;
+		update_radius();
+		return true;
 	}
-	return vpass->set_float(key, value);
+	return false;
 }
 
-SingleBlurPassEffect::SingleBlurPassEffect()
-	: radius(3.0f),
-	  direction(HORIZONTAL)
+SingleBlurPassEffect::SingleBlurPassEffect(BlurEffect *parent)
+	: parent(parent),
+	  radius(3.0f),
+	  direction(HORIZONTAL),
+ 	  width(1280),
+ 	  height(720)
 {
-	register_float("radius", (float *)&radius);
+	register_float("radius", &radius);
 	register_int("direction", (int *)&direction);
+	register_int("width", &width);
+	register_int("height", &height);
 }
 
 std::string SingleBlurPassEffect::output_fragment_shader()
@@ -48,45 +103,6 @@ void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 {
 	Effect::set_gl_state(glsl_program_num, prefix, sampler_num);
 
-	int base_texture_size, texture_size;
-	if (direction == HORIZONTAL) {
-		base_texture_size = texture_size = 1280;  // FIXME
-	} else if (direction == VERTICAL) {
-		base_texture_size = texture_size = 720;  // FIXME
-	} else {
-		assert(false);
-	}
-
-	// 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.
-	//
-	// FIXME: we really need to pick the same mipmap level for both horizontal and vertical!
-	unsigned base_mipmap_level = 0;
-	float adjusted_radius = radius;
-	while (texture_size > 1 && adjusted_radius * 2.5f > NUM_TAPS / 2) {
-		++base_mipmap_level;
-		texture_size /= 2;  // Rounding down.
-		adjusted_radius = radius * float(texture_size) / float(base_texture_size);
-	}
-
-	// In the second pass, we do the same, but don't sample from a mipmap;
-	// that would re-blur the other direction in an ugly fashion, and we already
-	// have the vertical box blur we need from that pass.
-	//
-	// TODO: We really need to present horizontal+vertical as a unit;
-	// currently, there's really no guarantee vertical blur is the second pass.
-	if (direction == VERTICAL) {
-		base_mipmap_level = 0;
-	}
-
-	glActiveTexture(GL_TEXTURE0);
-	check_error();
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, base_mipmap_level);
-	check_error();
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, base_mipmap_level);
-	check_error();
-
 	// Compute the weights; they will be symmetrical, so we only compute
 	// the right side.
 	float weight[NUM_TAPS + 1];
@@ -98,12 +114,16 @@ void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 	} else {
 		float sum = 0.0f;
 		for (unsigned i = 0; i < NUM_TAPS + 1; ++i) {
-			float z = i / adjusted_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) {
@@ -117,9 +137,6 @@ void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 		}
 	}
 
-#if 0
-	// NOTE: This is currently broken.
-
 	// 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
@@ -145,24 +162,14 @@ void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 		float w2 = weight[base_pos + 1];
 
 		float offset, total_weight;
-		if (w1 + w2 < 1e-6) {
-			offset = 0.5f;
-			total_weight = 0.0f;
-		} else {
-			offset = w2 / (w1 + w2);
-			total_weight = w1 + w2;
-		}
-#if 0
-		// hack for easier visualization
-		offset = 0.5f;
-		total_weight = 8.0f;
-#endif
+		combine_two_samples(w1, w2, &offset, &total_weight, NULL);
+
 		float x = 0.0f, y = 0.0f;
 
 		if (direction == HORIZONTAL) {
-			x = (base_pos + offset) / (float)texture_size;
+			x = (base_pos + offset) / (float)width;
 		} else if (direction == VERTICAL) {
-			y = (base_pos + offset) / (float)texture_size;
+			y = (base_pos + offset) / (float)height;
 		} else {
 			assert(false);
 		}
@@ -174,38 +181,8 @@ void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 	}
 
 	set_uniform_vec4_array(glsl_program_num, prefix, "samples", samples, NUM_TAPS / 2 + 1);
-#else
-	// Boring, at-whole-pixels sampling.
-	float samples[4 * NUM_TAPS];
-
-	// All other samples.
-	for (unsigned i = 0; i < NUM_TAPS + 1; ++i) {
-		float x = 0.0f, y = 0.0f;
-
-		if (direction == HORIZONTAL) {
-			x = i / (float)texture_size;
-		} else if (direction == VERTICAL) {
-			y = i / (float)texture_size;
-		} else {
-			assert(false);
-		}
-
-		samples[4 * i + 0] = x;
-		samples[4 * i + 1] = y;
-		samples[4 * i + 2] = weight[i];
-		samples[4 * i + 3] = 0.0f;
-	}
-
-	set_uniform_vec4_array(glsl_program_num, prefix, "samples", samples, NUM_TAPS + 1);
-#endif
 }
 
 void SingleBlurPassEffect::clear_gl_state()
 {
-	glActiveTexture(GL_TEXTURE0);
-	check_error();
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
-	check_error();
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1000);
-	check_error();
 }