X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=resample_effect.cpp;h=ba8a71c0241443c0730a5ce99d68a2fa7c014ad3;hp=958ed25b9c035a9ca1ad59109294b9cc96ed97ff;hb=90ac46cdc5845432df13385f946c63b5496c685e;hpb=6bf496a34a84fb14b1b3b6debfd42ba36568b879 diff --git a/resample_effect.cpp b/resample_effect.cpp index 958ed25..ba8a71c 100644 --- a/resample_effect.cpp +++ b/resample_effect.cpp @@ -1,7 +1,7 @@ // Three-lobed Lanczos, the most common choice. // Note that if you change this, the accuracy for LANCZOS_TABLE_SIZE // needs to be recomputed. -#define LANCZOS_RADIUS 3.0 +#define LANCZOS_RADIUS 3.0f #include #include @@ -27,12 +27,6 @@ namespace movit { namespace { -template -struct Tap { - T weight; - T pos; -}; - float sinc(float x) { if (fabs(x) < 1e-6) { @@ -74,6 +68,9 @@ float lanczos_weight(float x) // // Solve for e = 1e-6 yields a step size of 0.0027, which to cover the range // 0..3 needs 1109 steps. We round up to the next power of two, just to be sure. +// +// You need to call lanczos_table_init_done before the first call to +// lanczos_weight_cached. #define LANCZOS_TABLE_SIZE 2048 bool lanczos_table_init_done = false; float lanczos_table[LANCZOS_TABLE_SIZE + 2]; @@ -88,17 +85,12 @@ void init_lanczos_table() float lanczos_weight_cached(float x) { - if (!lanczos_table_init_done) { - // Could in theory race between two threads if we are unlucky, - // but that is harmless, since they'll write the same data. - init_lanczos_table(); - } x = fabs(x); if (x > LANCZOS_RADIUS) { return 0.0f; } float table_pos = x * (LANCZOS_TABLE_SIZE / LANCZOS_RADIUS); - int table_pos_int = int(table_pos); // Truncate towards zero. + unsigned table_pos_int = int(table_pos); // Truncate towards zero. float table_pos_frac = table_pos - table_pos_int; assert(table_pos < LANCZOS_TABLE_SIZE + 2); return lanczos_table[table_pos_int] + @@ -194,13 +186,13 @@ template void normalize_sum(Tap* vals, unsigned num) { for (int normalize_pass = 0; normalize_pass < 2; ++normalize_pass) { - double sum = 0.0; + float sum = 0.0; for (unsigned i = 0; i < num; ++i) { - sum += to_fp64(vals[i].weight); + sum += to_fp32(vals[i].weight); } - double inv_sum = 1.0 / sum; + float inv_sum = 1.0 / sum; for (unsigned i = 0; i < num; ++i) { - vals[i].weight = from_fp64(to_fp64(vals[i].weight) * inv_sum); + vals[i].weight = from_fp32(to_fp32(vals[i].weight) * inv_sum); } } } @@ -214,7 +206,7 @@ void normalize_sum(Tap* vals, unsigned num) // // The greedy strategy for combining samples is optimal. template -unsigned combine_many_samples(const Tap *weights, unsigned src_size, unsigned src_samples, unsigned dst_samples, Tap **bilinear_weights) +unsigned combine_many_samples(const Tap *weights, unsigned src_size, unsigned src_samples, unsigned dst_samples, unique_ptr[]> *bilinear_weights) { float num_subtexels = src_size / movit_texel_subpixel_precision; float inv_num_subtexels = movit_texel_subpixel_precision / src_size; @@ -227,9 +219,9 @@ unsigned combine_many_samples(const Tap *weights, unsigned src_size, unsi // Now that we know the right width, actually combine the samples. unsigned src_bilinear_samples = src_samples - max_samples_saved; - *bilinear_weights = new Tap[dst_samples * src_bilinear_samples]; + bilinear_weights->reset(new Tap[dst_samples * src_bilinear_samples]); for (unsigned y = 0; y < dst_samples; ++y) { - Tap *bilinear_weights_ptr = *bilinear_weights + y * src_bilinear_samples; + Tap *bilinear_weights_ptr = bilinear_weights->get() + y * src_bilinear_samples; unsigned num_samples_saved = combine_samples( weights + y * src_samples, bilinear_weights_ptr, @@ -257,10 +249,10 @@ double compute_sum_sq_error(const Tap* weights, unsigned num_weights, // Find the effective range of the bilinear-optimized kernel. // Due to rounding of the positions, this is not necessarily the same // as the intended range (ie., the range of the original weights). - int lower_pos = int(floor(to_fp64(bilinear_weights[0].pos) * size - 0.5)); - int upper_pos = int(ceil(to_fp64(bilinear_weights[num_bilinear_weights - 1].pos) * size - 0.5)) + 2; - lower_pos = min(lower_pos, lrintf(weights[0].pos * size - 0.5)); - upper_pos = max(upper_pos, lrintf(weights[num_weights - 1].pos * size - 0.5) + 1); + int lower_pos = int(floor(to_fp32(bilinear_weights[0].pos) * size - 0.5f)); + int upper_pos = int(ceil(to_fp32(bilinear_weights[num_bilinear_weights - 1].pos) * size - 0.5f)) + 2; + lower_pos = min(lower_pos, lrintf(weights[0].pos * size - 0.5f)); + upper_pos = max(upper_pos, lrintf(weights[num_weights - 1].pos * size - 0.5f) + 1); float* effective_weights = new float[upper_pos - lower_pos]; for (int i = 0; i < upper_pos - lower_pos; ++i) { @@ -269,7 +261,7 @@ double compute_sum_sq_error(const Tap* weights, unsigned num_weights, // Now find the effective weights that result from this sampling. for (unsigned i = 0; i < num_bilinear_weights; ++i) { - const float pixel_pos = to_fp64(bilinear_weights[i].pos) * size - 0.5f; + const float pixel_pos = to_fp32(bilinear_weights[i].pos) * size - 0.5f; const int x0 = int(floor(pixel_pos)) - lower_pos; const int x1 = x0 + 1; const float f = lrintf((pixel_pos - (x0 + lower_pos)) / movit_texel_subpixel_precision) * movit_texel_subpixel_precision; @@ -279,8 +271,8 @@ double compute_sum_sq_error(const Tap* weights, unsigned num_weights, assert(x0 < upper_pos - lower_pos); assert(x1 < upper_pos - lower_pos); - effective_weights[x0] += to_fp64(bilinear_weights[i].weight) * (1.0 - f); - effective_weights[x1] += to_fp64(bilinear_weights[i].weight) * f; + effective_weights[x0] += to_fp32(bilinear_weights[i].weight) * (1.0f - f); + effective_weights[x1] += to_fp32(bilinear_weights[i].weight) * f; } // Subtract the desired weights to get the error. @@ -461,6 +453,12 @@ SingleResamplePassEffect::SingleResamplePassEffect(ResampleEffect *parent) register_uniform_float("whole_pixel_offset", &uniform_whole_pixel_offset); glGenTextures(1, &texnum); + + if (!lanczos_table_init_done) { + // Could in theory race between two threads if we are unlucky, + // but that is harmless, since they'll write the same data. + init_lanczos_table(); + } } SingleResamplePassEffect::~SingleResamplePassEffect() @@ -502,12 +500,68 @@ void SingleResamplePassEffect::update_texture(GLuint glsl_program_num, const str assert(false); } + ScalingWeights weights = calculate_scaling_weights(src_size, dst_size, zoom, offset); + src_bilinear_samples = weights.src_bilinear_samples; + num_loops = weights.num_loops; + slice_height = 1.0f / weights.num_loops; + + // Encode as a two-component texture. Note the GL_REPEAT. + glActiveTexture(GL_TEXTURE0 + *sampler_num); + check_error(); + glBindTexture(GL_TEXTURE_2D, texnum); + check_error(); + if (last_texture_width == -1) { + // Need to set this state the first time. + glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); + check_error(); + glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); + check_error(); + glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); + check_error(); + } + + GLenum type, internal_format; + void *pixels; + assert((weights.bilinear_weights_fp16 == nullptr) != (weights.bilinear_weights_fp32 == nullptr)); + if (weights.bilinear_weights_fp32 != nullptr) { + type = GL_FLOAT; + internal_format = GL_RG32F; + pixels = weights.bilinear_weights_fp32.get(); + } else { + type = GL_HALF_FLOAT; + internal_format = GL_RG16F; + pixels = weights.bilinear_weights_fp16.get(); + } + + if (int(weights.src_bilinear_samples) == last_texture_width && + int(weights.dst_samples) == last_texture_height && + internal_format == last_texture_internal_format) { + // Texture dimensions and type are unchanged; it is more efficient + // to just update it rather than making an entirely new texture. + glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, weights.src_bilinear_samples, weights.dst_samples, GL_RG, type, pixels); + } else { + glTexImage2D(GL_TEXTURE_2D, 0, internal_format, weights.src_bilinear_samples, weights.dst_samples, 0, GL_RG, type, pixels); + last_texture_width = weights.src_bilinear_samples; + last_texture_height = weights.dst_samples; + last_texture_internal_format = internal_format; + } + check_error(); +} + +ScalingWeights calculate_scaling_weights(unsigned src_size, unsigned dst_size, float zoom, float offset) +{ + if (!lanczos_table_init_done) { + // Only needed if run from outside ResampleEffect. + init_lanczos_table(); + } + // For many resamplings (e.g. 640 -> 1280), we will end up with the same // set of samples over and over again in a loop. Thus, we can compute only // the first such loop, and then ask the card to repeat the texture for us. // This is both easier on the texture cache and lowers our CPU cost for // generating the kernel somewhat. float scaling_factor; + int num_loops; if (fabs(zoom - 1.0f) < 1e-6) { num_loops = gcd(src_size, dst_size); scaling_factor = float(dst_size) / float(src_size); @@ -520,7 +574,6 @@ void SingleResamplePassEffect::update_texture(GLuint glsl_program_num, const str num_loops = 1; scaling_factor = zoom * float(dst_size) / float(src_size); } - slice_height = 1.0f / num_loops; unsigned dst_samples = dst_size / num_loops; // Sample the kernel in the right place. A diagram with a triangular kernel @@ -575,7 +628,7 @@ void SingleResamplePassEffect::update_texture(GLuint glsl_program_num, const str float radius_scaling_factor = min(scaling_factor, 1.0f); int int_radius = lrintf(LANCZOS_RADIUS / radius_scaling_factor); int src_samples = int_radius * 2 + 1; - Tap *weights = new Tap[dst_samples * src_samples]; + unique_ptr[]> weights(new Tap[dst_samples * src_samples]); float subpixel_offset = offset - lrintf(offset); // The part not covered by whole_pixel_offset. assert(subpixel_offset >= -0.5f && subpixel_offset <= 0.5f); for (unsigned y = 0; y < dst_samples; ++y) { @@ -585,11 +638,12 @@ void SingleResamplePassEffect::update_texture(GLuint glsl_program_num, const str int base_src_y = lrintf(center_src_y); // Now sample pixels on each side around that point. + float inv_src_size = 1.0 / float(src_size); for (int i = 0; i < src_samples; ++i) { int src_y = base_src_y + i - int_radius; float weight = lanczos_weight_cached(radius_scaling_factor * (src_y - center_src_y - subpixel_offset)); weights[y * src_samples + i].weight = weight * radius_scaling_factor; - weights[y * src_samples + i].pos = (src_y + 0.5) / float(src_size); + weights[y * src_samples + i].pos = (src_y + 0.5f) * inv_src_size; } } @@ -598,15 +652,14 @@ void SingleResamplePassEffect::update_texture(GLuint glsl_program_num, const str // Our tolerance level for total error is a bit higher than the one for invididual // samples, since one would assume overall errors in the shape don't matter as much. const float max_error = 2.0f / (255.0f * 255.0f); - Tap *bilinear_weights_fp16; - src_bilinear_samples = combine_many_samples(weights, src_size, src_samples, dst_samples, &bilinear_weights_fp16); - Tap *bilinear_weights_fp32 = NULL; - bool fallback_to_fp32 = false; + unique_ptr[]> bilinear_weights_fp16; + int src_bilinear_samples = combine_many_samples(weights.get(), src_size, src_samples, dst_samples, &bilinear_weights_fp16); + unique_ptr[]> bilinear_weights_fp32 = NULL; double max_sum_sq_error_fp16 = 0.0; for (unsigned y = 0; y < dst_samples; ++y) { double sum_sq_error_fp16 = compute_sum_sq_error( - weights + y * src_samples, src_samples, - bilinear_weights_fp16 + y * src_bilinear_samples, src_bilinear_samples, + weights.get() + y * src_samples, src_samples, + bilinear_weights_fp16.get() + y * src_bilinear_samples, src_bilinear_samples, src_size); max_sum_sq_error_fp16 = std::max(max_sum_sq_error_fp16, sum_sq_error_fp16); if (max_sum_sq_error_fp16 > max_error) { @@ -615,54 +668,17 @@ void SingleResamplePassEffect::update_texture(GLuint glsl_program_num, const str } if (max_sum_sq_error_fp16 > max_error) { - fallback_to_fp32 = true; - src_bilinear_samples = combine_many_samples(weights, src_size, src_samples, dst_samples, &bilinear_weights_fp32); - } - - // Encode as a two-component texture. Note the GL_REPEAT. - glActiveTexture(GL_TEXTURE0 + *sampler_num); - check_error(); - glBindTexture(GL_TEXTURE_2D, texnum); - check_error(); - if (last_texture_width == -1) { - // Need to set this state the first time. - glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); - check_error(); - glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); - check_error(); - glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); - check_error(); + bilinear_weights_fp16.reset(); + src_bilinear_samples = combine_many_samples(weights.get(), src_size, src_samples, dst_samples, &bilinear_weights_fp32); } - GLenum type, internal_format; - void *pixels; - if (fallback_to_fp32) { - type = GL_FLOAT; - internal_format = GL_RG32F; - pixels = bilinear_weights_fp32; - } else { - type = GL_HALF_FLOAT; - internal_format = GL_RG16F; - pixels = bilinear_weights_fp16; - } - - if (int(src_bilinear_samples) == last_texture_width && - int(dst_samples) == last_texture_height && - internal_format == last_texture_internal_format) { - // Texture dimensions and type are unchanged; it is more efficient - // to just update it rather than making an entirely new texture. - glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, src_bilinear_samples, dst_samples, GL_RG, type, pixels); - } else { - glTexImage2D(GL_TEXTURE_2D, 0, internal_format, src_bilinear_samples, dst_samples, 0, GL_RG, type, pixels); - last_texture_width = src_bilinear_samples; - last_texture_height = dst_samples; - last_texture_internal_format = internal_format; - } - check_error(); - - delete[] weights; - delete[] bilinear_weights_fp16; - delete[] bilinear_weights_fp32; + ScalingWeights ret; + ret.src_bilinear_samples = src_bilinear_samples; + ret.dst_samples = dst_samples; + ret.num_loops = num_loops; + ret.bilinear_weights_fp16 = move(bilinear_weights_fp16); + ret.bilinear_weights_fp32 = move(bilinear_weights_fp32); + return ret; } void SingleResamplePassEffect::set_gl_state(GLuint glsl_program_num, const string &prefix, unsigned *sampler_num) @@ -713,10 +729,12 @@ void SingleResamplePassEffect::set_gl_state(GLuint glsl_program_num, const strin // We specifically do not want mipmaps on the input texture; // they break minification. Node *self = chain->find_node_for_effect(this); - glActiveTexture(chain->get_input_sampler(self, 0)); - check_error(); - glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); - check_error(); + if (chain->has_input_sampler(self, 0)) { + glActiveTexture(chain->get_input_sampler(self, 0)); + check_error(); + glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); + check_error(); + } } } // namespace movit