Fix for half pixel offset rasterizing masks

1 files changed, 6 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/mask_rasterize.c b/source/blender/blenkernel/intern/mask_rasterize.c
index 92628387dc6..ea039dabce4 100644
--- a/source/blender/blenkernel/intern/mask_rasterize.c
+++ b/source/blender/blenkernel/intern/mask_rasterize.c
@@ -1434,6 +1434,10 @@ void BKE_maskrasterize_buffer(MaskRasterHandle *mr_handle,
                               const unsigned int width, const unsigned int height,
                               float *buffer)
 {
+	const float x_inv = 1.0f / (float)width;
+	const float y_inv = 1.0f / (float)height;
+	const float x_px_ofs = x_inv * 0.5f;
+	const float y_px_ofs = y_inv * 0.5f;
 #ifdef _MSC_VER
 	int y;  /* msvc requires signed for some reason */
 
@@ -1449,9 +1453,9 @@ void BKE_maskrasterize_buffer(MaskRasterHandle *mr_handle,
 		unsigned int i = y * width;
 		unsigned int x;
 		float xy[2];
-		xy[1] = (float)y / (float)height;
+		xy[1] = ((float)y * y_inv) + y_px_ofs;
 		for (x = 0; x < width; x++, i++) {
-			xy[0] = (float)x / (float)width;
+			xy[0] = ((float)x * x_inv) + x_px_ofs;
 
 			buffer[i] = BKE_maskrasterize_handle_sample(mr_handle, xy);
 		}