Fix part of T41406

Attempt to make soften brush faster by allowing non-symmetric kernels.
Projective painting supports those naturally but for 2D painting there's
a small hack to avoid shifting of the texture. Not totally correct but
it works for now.

1 files changed, 6 insertions, 13 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_image.c b/source/blender/editors/sculpt_paint/paint_image.c
index a556f22b8ec..85c76c24f35 100644
--- a/source/blender/editors/sculpt_paint/paint_image.c
+++ b/source/blender/editors/sculpt_paint/paint_image.c
@@ -515,10 +515,10 @@ BlurKernel *paint_new_blur_kernel(Brush *br)
 {
 	int i, j;
 	BlurKernel *kernel = MEM_mallocN(sizeof(BlurKernel), "blur kernel");
-	int pixel_len = br->blur_kernel_radius;
+	float pixel_len = br->blur_kernel_radius / 2.0f;
 	BlurKernelType type = br->blur_mode;
 
-	kernel->side = pixel_len * 2 + 1;
+	kernel->side = br->blur_kernel_radius + 1;
 	kernel->side_squared = kernel->side * kernel->side;
 	kernel->wdata = MEM_mallocN(sizeof(float) * kernel->side_squared, "blur kernel data");
 	kernel->pixel_len = pixel_len;
@@ -531,26 +531,19 @@ BlurKernel *paint_new_blur_kernel(Brush *br)
 
 		case KERNEL_GAUSSIAN:
 		{
-			float standard_dev = pixel_len / 3.0; /* at standard deviation of 3.0 kernel is at about zero */
-			int i_term = pixel_len + 1;
+			float standard_dev = pixel_len / 3.0f; /* at standard deviation of 3.0 kernel is at about zero */
 
 			/* make the necessary adjustment to the value for use in the normal distribution formula */
 			standard_dev = standard_dev * standard_dev * 2;
 
-			kernel->wdata[pixel_len + pixel_len * kernel->side] = 1.0;
-			/* fill in all four quadrants at once */
-			for (i = 0; i < i_term; i++) {
-				for (j = 0; j < pixel_len; j++) {
+			for (i = 0; i < kernel->side; i++) {
+				for (j = 0; j < kernel->side; j++) {
 					float idist = pixel_len - i;
 					float jdist = pixel_len - j;
 
 					float value = exp((idist * idist + jdist * jdist) / standard_dev);
 
-					kernel->wdata[i + j * kernel->side] =
-					kernel->wdata[(kernel->side - j - 1) + i * kernel->side] =
-					kernel->wdata[(kernel->side - i - 1) + (kernel->side - j - 1) * kernel->side] =
-					kernel->wdata[j + (kernel->side - i - 1) * kernel->side] =
-						value;
+					kernel->wdata[i + j * kernel->side] = value;
 				}
 			}