fix for harmless glitch rotating the camera in camera mode, having the center point so close to the viewpoint caused the helper line to erratically move about because of float precision.

1 files changed, 22 insertions, 14 deletions

diff --git a/source/blender/editors/space_view3d/view3d_project.c b/source/blender/editors/space_view3d/view3d_project.c
index c428cb02236..bc1656ff7c6 100644
--- a/source/blender/editors/space_view3d/view3d_project.c
+++ b/source/blender/editors/space_view3d/view3d_project.c
@@ -43,6 +43,7 @@
 #include "ED_view3d.h"  /* own include */
 
 #define BL_NEAR_CLIP 0.001
+#define BL_ZERO_CLIP 0.001
 
 /* Non Clipping Projection Functions
  * ********************************* */
@@ -134,18 +135,25 @@ static eV3DProjStatus ed_view3d_project__internal(ARegion *ar,
 	vec4[3] = 1.0;
 	mul_m4_v4(perspmat, vec4);
 
-	if (((flag & V3D_PROJ_TEST_CLIP_NEAR) == 0)  || (vec4[3] > (float)BL_NEAR_CLIP)) {
-		const float scalar = (vec4[3] != 0.0f) ? (1.0f / vec4[3]): 0.0f;
-		const float fx = ((float)ar->winx / 2.0f) * (1.0f + (vec4[0] * scalar));
-		if (((flag & V3D_PROJ_TEST_CLIP_WIN) == 0) || (fx > 0.0f && fx < (float)ar->winx)) {
-			const float fy = ((float)ar->winy / 2.0f) * (1.0f + (vec4[1] * scalar));
-			if (((flag & V3D_PROJ_TEST_CLIP_WIN) == 0) || (fy > 0.0f && fy < (float)ar->winy)) {
-				r_co[0] = floorf(fx);
-				r_co[1] = floorf(fy);
-
-				/* check if the point is behind the view, we need to flip in this case */
-				if (UNLIKELY((flag & V3D_PROJ_TEST_CLIP_NEAR) == 0) && (vec4[3] < 0.0f)) {
-					negate_v2(r_co);
+
+
+	if (((flag & V3D_PROJ_TEST_CLIP_ZERO) == 0) || (fabsf(vec4[3]) > (float)BL_ZERO_CLIP)) {
+		if (((flag & V3D_PROJ_TEST_CLIP_NEAR) == 0)  || (vec4[3] > (float)BL_NEAR_CLIP)) {
+			const float scalar = (vec4[3] != 0.0f) ? (1.0f / vec4[3]): 0.0f;
+			const float fx = ((float)ar->winx / 2.0f) * (1.0f + (vec4[0] * scalar));
+			if (((flag & V3D_PROJ_TEST_CLIP_WIN) == 0) || (fx > 0.0f && fx < (float)ar->winx)) {
+				const float fy = ((float)ar->winy / 2.0f) * (1.0f + (vec4[1] * scalar));
+				if (((flag & V3D_PROJ_TEST_CLIP_WIN) == 0) || (fy > 0.0f && fy < (float)ar->winy)) {
+					r_co[0] = floorf(fx);
+					r_co[1] = floorf(fy);
+
+					/* check if the point is behind the view, we need to flip in this case */
+					if (UNLIKELY((flag & V3D_PROJ_TEST_CLIP_NEAR) == 0) && (vec4[3] < 0.0f)) {
+						negate_v2(r_co);
+					}
+				}
+				else {
+					return V3D_PROJ_RET_CLIP_WIN;
 				}
 			}
 			else {
@@ -153,11 +161,11 @@ static eV3DProjStatus ed_view3d_project__internal(ARegion *ar,
 			}
 		}
 		else {
-			return V3D_PROJ_RET_CLIP_WIN;
+			return V3D_PROJ_RET_CLIP_NEAR;
 		}
 	}
 	else {
-		return V3D_PROJ_RET_CLIP_NEAR;
+		return V3D_PROJ_RET_CLIP_ZERO;
 	}
 
 	return V3D_PROJ_RET_OK;