X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=blur_effect.cpp;h=90d1b68653b9af51c009c1fae48a7e007998da8d;hp=f2d5d038e6ac57105441c71de2b60e4b8942f0e8;hb=b09a4cb8dec09bcd1e42026d5b229b57e620e47c;hpb=b618b34070d23b6da35c77f004678d8a9e55575b diff --git a/blur_effect.cpp b/blur_effect.cpp index f2d5d03..90d1b68 100644 --- a/blur_effect.cpp +++ b/blur_effect.cpp @@ -1,41 +1,97 @@ -#define GL_GLEXT_PROTOTYPES 1 - #include -#include -#include #include #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(std::vector *chain) { - hpass->add_self_to_effect_chain(chain); - vpass->add_self_to_effect_chain(chain); +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); + + 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() @@ -43,48 +99,9 @@ std::string SingleBlurPassEffect::output_fragment_shader() return read_file("blur_effect.frag"); } -void SingleBlurPassEffect::set_uniforms(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num) +void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num) { - Effect::set_uniforms(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(); + Effect::set_gl_state(glsl_program_num, prefix, sampler_num); // Compute the weights; they will be symmetrical, so we only compute // the right side. @@ -97,12 +114,16 @@ void SingleBlurPassEffect::set_uniforms(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) { @@ -116,9 +137,6 @@ void SingleBlurPassEffect::set_uniforms(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 @@ -144,24 +162,14 @@ void SingleBlurPassEffect::set_uniforms(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); + 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); } @@ -173,28 +181,8 @@ void SingleBlurPassEffect::set_uniforms(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() +{ }