X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=blur_effect.cpp;h=c8cf539e0542a3184d9f6d1f1d7d23acc77752d6;hp=7ca895a15f6b56b8dfee4e53a0f013610097d0de;hb=3d1f6c11c53cd9d3d5c1fb60f4accf050b7f135e;hpb=75c27c449aabb27ed0b028b57b20d70005a6e447 diff --git a/blur_effect.cpp b/blur_effect.cpp index 7ca895a..c8cf539 100644 --- a/blur_effect.cpp +++ b/blur_effect.cpp @@ -1,56 +1,171 @@ -#define GL_GLEXT_PROTOTYPES 1 - #include -#include -#include +#include #include "blur_effect.h" #include "util.h" +#include "opengl.h" +// Must match blur_effect.frag. +#define NUM_TAPS 16 + BlurEffect::BlurEffect() : radius(3.0f) { - register_float("radius", (float *)&radius); -} + hpass = new SingleBlurPassEffect(); + hpass->set_int("direction", SingleBlurPassEffect::HORIZONTAL); + vpass = new SingleBlurPassEffect(); + vpass->set_int("direction", SingleBlurPassEffect::VERTICAL); -std::string BlurEffect::output_fragment_shader() -{ - return read_file("blur_effect.frag"); + update_radius(); } -void BlurEffect::set_uniforms(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num) +void BlurEffect::add_self_to_effect_chain(EffectChain *chain, const std::vector &inputs) { - Effect::set_uniforms(glsl_program_num, prefix, sampler_num); + assert(inputs.size() == 1); + hpass->add_self_to_effect_chain(chain, inputs); - // We only have 15 taps to work with, 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. + std::vector vpass_inputs; + vpass_inputs.push_back(hpass); + vpass->add_self_to_effect_chain(chain, vpass_inputs); +} + +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; float adjusted_radius = radius; - float pixel_size = 1.0f; - while (adjusted_radius * 2.5f > 7.0f) { + while (adjusted_radius * 1.5f > NUM_TAPS / 2) { ++base_mipmap_level; - adjusted_radius *= 0.5f; - pixel_size *= 2.0f; - } - - glActiveTexture(GL_TEXTURE0); - glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, base_mipmap_level); - check_error(); - - set_uniform_float(glsl_program_num, prefix, "pixel_offset", pixel_size / 1280.0f); // FIXME - - // Simple Gaussian weights for now. - float weight[15], total = 0.0f; - for (unsigned i = 0; i < 15; ++i) { - float z = (i - 7.0f) / adjusted_radius; - weight[i] = exp(-(z*z)); - total += weight[i]; + adjusted_radius /= 2.0f; } - printf("[mip level %d] ", base_mipmap_level); - for (unsigned i = 0; i < 15; ++i) { - weight[i] /= total; - printf("%f ", weight[i]); + + 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 |= 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 + + assert(ok); +} + +bool BlurEffect::set_float(const std::string &key, float value) { + if (key == "radius") { + radius = value; + update_radius(); + return true; } - printf("\n"); - set_uniform_float_array(glsl_program_num, prefix, "weight", weight, 15); + return false; +} + +SingleBlurPassEffect::SingleBlurPassEffect() + : radius(3.0f), + direction(HORIZONTAL), + width(1280), + height(720) +{ + register_float("radius", &radius); + register_int("direction", (int *)&direction); + register_int("width", &width); + register_int("height", &height); +} + +std::string SingleBlurPassEffect::output_fragment_shader() +{ + return read_file("blur_effect.frag"); +} + +void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const std::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[NUM_TAPS + 1]; + if (radius < 1e-3) { + weight[0] = 1.0f; + for (unsigned i = 1; i < NUM_TAPS + 1; ++i) { + weight[i] = 0.0f; + } + } 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. + weight[i] = 1.0f / (cosh(z) * cosh(z)); + + if (i == 0) { + sum += weight[i]; + } else { + sum += 2.0f * weight[i]; + } + } + for (unsigned 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. + float samples[4 * (NUM_TAPS / 2 + 1)]; + + // Center sample. + samples[4 * 0 + 0] = 0.0f; + samples[4 * 0 + 1] = 0.0f; + samples[4 * 0 + 2] = weight[0]; + samples[4 * 0 + 3] = 0.0f; + + // All other samples. + for (unsigned 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 offset, total_weight; + if (w1 + w2 < 1e-6) { + offset = 0.5f; + total_weight = 0.0f; + } else { + offset = w2 / (w1 + w2); + total_weight = w1 + w2; + } + float x = 0.0f, y = 0.0f; + + if (direction == HORIZONTAL) { + x = (base_pos + offset) / (float)width; + } else if (direction == VERTICAL) { + y = (base_pos + offset) / (float)height; + } else { + assert(false); + } + + samples[4 * i + 0] = x; + samples[4 * i + 1] = y; + samples[4 * i + 2] = total_weight; + samples[4 * i + 3] = 0.0f; + } + + set_uniform_vec4_array(glsl_program_num, prefix, "samples", samples, NUM_TAPS / 2 + 1); +} + +void SingleBlurPassEffect::clear_gl_state() +{ }