diff --git a/blur.c b/blur.c index b0349d5..8434e81 100644 --- a/blur.c +++ b/blur.c @@ -69,7 +69,8 @@ blur_image_surface (cairo_surface_t *surface, int radius) dst = (uint32_t*)cairo_image_surface_get_data (tmp); dst_stride = cairo_image_surface_get_stride (tmp); - blur_impl_naive(src, dst, width, height, src_stride, dst_stride, 10000); + //blur_impl_naive(src, dst, width, height, src_stride, dst_stride, 10000); + blur_impl_sse2(src, dst, width, height, 2.5); cairo_surface_destroy (tmp); cairo_surface_flush (surface); diff --git a/blur.h b/blur.h index 1c1eb7a..2a5f45c 100644 --- a/blur.h +++ b/blur.h @@ -6,6 +6,8 @@ void blur_image_surface (cairo_surface_t *surface, int radius); void blur_impl_naive(uint32_t* src, uint32_t* dst, int width, int height, int src_stride, int dst_stride, int radius); +void blur_impl_sse2(uint32_t* src, uint32_t* dst, int width, int height, float sigma); +void blur_impl_horizontal_pass_sse2(uint32_t *src, uint32_t *dst, float *kernel, int width, int height); #endif diff --git a/blur_simd.c b/blur_simd.c new file mode 100644 index 0000000..2186cf5 --- /dev/null +++ b/blur_simd.c @@ -0,0 +1,116 @@ +/* + * vim:ts=4:sw=4:expandtab + * + * © 2016 Sebastian Frysztak + * + * See LICENSE for licensing information + * + */ + +#include "blur.h" +#include +#include + +#define ALIGN16 __attribute__((aligned(16))) +#define KERNEL_SIZE 7 +#define HALF_KERNEL KERNEL_SIZE / 2 + +void blur_impl_sse2(uint32_t *src, uint32_t *dst, int width, int height, float sigma) { + // prepare kernel + float kernel[KERNEL_SIZE]; + float coeff = 1.0 / sqrtf(2 * M_PI * sigma * sigma), sum = 0; + + for (int i = 0; i < KERNEL_SIZE; i++) { + float x = HALF_KERNEL - i; + kernel[i] = coeff * expf(-x * x / (2.0 * sigma * sigma)); + sum += kernel[i]; + } + + // normalize kernel + for (int i = 0; i < KERNEL_SIZE; i++) + kernel[i] /= sum; + + // horizontal pass includes image transposition: + // instead of writing pixel src[x] to dst[x], + // we write it to transposed location. + // (to be exact: dst[height * current_column + current_row]) + blur_impl_horizontal_pass_sse2(src, dst, kernel, width, height); + blur_impl_horizontal_pass_sse2(dst, src, kernel, height, width); +} + +void blur_impl_horizontal_pass_sse2(uint32_t *src, uint32_t *dst, float *kernel, int width, int height) { + for (int row = 0; row < height; row++) { + // remember first and last pixel in a row + // (used to handle borders) + uint32_t firstPixel = *src; + uint32_t lastPixel = *(src + width - 1); + + for (int column = 0; column < width; column++, src++) { + __m128i rgbaIn1, rgbaIn2; + + // handle borders + int leftBorder = column < HALF_KERNEL; + int rightBorder = column + HALF_KERNEL >= width; + if (leftBorder || rightBorder) { + uint32_t rgbaIn[KERNEL_SIZE] ALIGN16; + int i = 0; + if (leftBorder) { + // for kernel size 7x7 and column == 0, we have: + // x x x P0 P1 P2 P3 + // first loop fills x's with P0, second one loads P{0..3} + for (; i < HALF_KERNEL - column; i++) + rgbaIn[i] = firstPixel; + for (; i < KERNEL_SIZE; i++) + rgbaIn[i] = *(src + i - HALF_KERNEL); + } else { + for (; width < column; i++) + rgbaIn[i] = *(src - i - HALF_KERNEL); + for (; i < KERNEL_SIZE; i++) + rgbaIn[i] = lastPixel; + } + + rgbaIn1 = _mm_load_si128((__m128i *)(rgbaIn)); + rgbaIn2 = _mm_load_si128((__m128i *)(rgbaIn + 4)); + } else { + rgbaIn1 = _mm_loadu_si128((__m128i *)(src - 3)); + rgbaIn2 = _mm_loadu_si128((__m128i *)(src + 1)); + } + + // unpack each pixel, convert to float, + // multiply by corresponding kernel value + // and add to accumulator + __m128i tmp; + __m128i zero = _mm_setzero_si128(); + __m128 rgba_ps; + __m128 acc = _mm_setzero_ps(); + int counter = 0; + + tmp = _mm_unpacklo_epi8(rgbaIn1, zero); + rgba_ps = _mm_cvtepi32_ps(_mm_unpacklo_epi16(tmp, zero)); + acc = _mm_add_ps(acc, _mm_mul_ps(rgba_ps, _mm_set1_ps(kernel[counter++]))); + rgba_ps = _mm_cvtepi32_ps(_mm_unpackhi_epi16(tmp, zero)); + acc = _mm_add_ps(acc, _mm_mul_ps(rgba_ps, _mm_set1_ps(kernel[counter++]))); + + tmp = _mm_unpackhi_epi8(rgbaIn1, zero); + rgba_ps = _mm_cvtepi32_ps(_mm_unpacklo_epi16(tmp, zero)); + acc = _mm_add_ps(acc, _mm_mul_ps(rgba_ps, _mm_set1_ps(kernel[counter++]))); + rgba_ps = _mm_cvtepi32_ps(_mm_unpackhi_epi16(tmp, zero)); + acc = _mm_add_ps(acc, _mm_mul_ps(rgba_ps, _mm_set1_ps(kernel[counter++]))); + + tmp = _mm_unpacklo_epi8(rgbaIn2, zero); + rgba_ps = _mm_cvtepi32_ps(_mm_unpacklo_epi16(tmp, zero)); + acc = _mm_add_ps(acc, _mm_mul_ps(rgba_ps, _mm_set1_ps(kernel[counter++]))); + rgba_ps = _mm_cvtepi32_ps(_mm_unpackhi_epi16(tmp, zero)); + acc = _mm_add_ps(acc, _mm_mul_ps(rgba_ps, _mm_set1_ps(kernel[counter++]))); + + tmp = _mm_unpackhi_epi8(rgbaIn2, zero); + rgba_ps = _mm_cvtepi32_ps(_mm_unpacklo_epi16(tmp, zero)); + acc = _mm_add_ps(acc, _mm_mul_ps(rgba_ps, _mm_set1_ps(kernel[counter++]))); + + __m128i rgbaOut = _mm_cvtps_epi32(acc); + rgbaOut = _mm_packs_epi32(rgbaOut, zero); + rgbaOut = _mm_packus_epi16(rgbaOut, zero); + *(dst + height * column + row) = _mm_cvtsi128_si32(rgbaOut); + } + } +}