From 3662b8e18714ed9e3e29c7d55c951557fc5ae104 Mon Sep 17 00:00:00 2001 From: Sebastian Frysztak Date: Fri, 28 Oct 2016 17:36:43 +0200 Subject: [PATCH] Improve border handling for larger kernels. --- blur_simd.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/blur_simd.c b/blur_simd.c index 1628264..4cacb9a 100644 --- a/blur_simd.c +++ b/blur_simd.c @@ -44,33 +44,29 @@ void blur_impl_sse2(uint32_t *src, uint32_t *dst, int width, int height, float s 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 rgbaIn[REGISTERS_CNT]; // handle borders int leftBorder = column < HALF_KERNEL; - int rightBorder = column + HALF_KERNEL >= width; + int rightBorder = column > width - HALF_KERNEL; 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} + // first loop mirrors P{0..3} to fill x's, + // second one loads P{0..3} for (; i < HALF_KERNEL - column; i++) - _rgbaIn[i] = firstPixel; + _rgbaIn[i] = *(src + (HALF_KERNEL - i)); for (; i < KERNEL_SIZE; i++) - _rgbaIn[i] = *(src + i - HALF_KERNEL); + _rgbaIn[i] = *(src - (HALF_KERNEL - i)); } else { - for (; width < column; i++) - _rgbaIn[i] = *(src - i - HALF_KERNEL); - for (; i < KERNEL_SIZE; i++) - _rgbaIn[i] = lastPixel; + for (; i < width - column; i++) + _rgbaIn[i] = *(src + i); + for (int k = 0; i < KERNEL_SIZE; i++, k++) + _rgbaIn[i] = *(src - k); } for (int k = 0; k < REGISTERS_CNT; k++)