commit 3662b8e18714ed9e3e29c7d55c951557fc5ae104
parent afe41c5754a2871e4aa5852343363083bc551782
Author: Sebastian Frysztak <sebfry@gmail.com>
Date: Fri, 28 Oct 2016 17:36:43 +0200
Improve border handling for larger kernels.
Diffstat:
1 file changed, 9 insertions(+), 13 deletions(-)
diff --git 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++)
