Fix T59505: Knife tool cut preview line becomes black

The root of the problem is that KnifeTool_OpData->colors was not init in
some cases. But the reason is unknown as it seems to be random and the
init function was always called.

So instead on init the color only once, we query the colors each time
we draw the knife points.
The overhead of this approach is negligeable.

1 files changed, 13 insertions, 15 deletions

diff --git a/source/blender/editors/mesh/editmesh_knife.c b/source/blender/editors/mesh/editmesh_knife.c
index b89a7dd91a1..c95755b8cb5 100644
--- a/source/blender/editors/mesh/editmesh_knife.c
+++ b/source/blender/editors/mesh/editmesh_knife.c
@@ -213,8 +213,6 @@ typedef struct KnifeTool_OpData {
 	/* vector along view z axis (object space, normalized) */
 	float proj_zaxis[3];
 
-	KnifeColors colors;
-
 	/* run by the UI or not */
 	bool is_interactive;
 
@@ -1041,8 +1039,10 @@ static void knife_init_colors(KnifeColors *colors)
 static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void *arg)
 {
 	const KnifeTool_OpData *kcd = arg;
-	GPU_depth_test(false);
+	KnifeColors colors;
+	knife_init_colors(&colors);
 
+	GPU_depth_test(false);
 	glPolygonOffset(1.0f, 1.0f);
 
 	GPU_matrix_push();
@@ -1058,7 +1058,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 	immBindBuiltinProgram(GPU_SHADER_3D_UNIFORM_COLOR);
 
 	if (kcd->mode == MODE_DRAGGING) {
-		immUniformColor3ubv(kcd->colors.line);
+		immUniformColor3ubv(colors.line);
 		GPU_line_width(2.0);
 
 		immBegin(GPU_PRIM_LINES, 2);
@@ -1068,7 +1068,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 	}
 
 	if (kcd->prev.vert) {
-		immUniformColor3ubv(kcd->colors.point);
+		immUniformColor3ubv(colors.point);
 		GPU_point_size(11);
 
 		immBegin(GPU_PRIM_POINTS, 1);
@@ -1077,7 +1077,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 	}
 
 	if (kcd->prev.bmface) {
-		immUniformColor3ubv(kcd->colors.curpoint);
+		immUniformColor3ubv(colors.curpoint);
 		GPU_point_size(9);
 
 		immBegin(GPU_PRIM_POINTS, 1);
@@ -1086,7 +1086,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 	}
 
 	if (kcd->curr.edge) {
-		immUniformColor3ubv(kcd->colors.edge);
+		immUniformColor3ubv(colors.edge);
 		GPU_line_width(2.0);
 
 		immBegin(GPU_PRIM_LINES, 2);
@@ -1095,7 +1095,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 		immEnd();
 	}
 	else if (kcd->curr.vert) {
-		immUniformColor3ubv(kcd->colors.point);
+		immUniformColor3ubv(colors.point);
 		GPU_point_size(11);
 
 		immBegin(GPU_PRIM_POINTS, 1);
@@ -1104,7 +1104,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 	}
 
 	if (kcd->curr.bmface) {
-		immUniformColor3ubv(kcd->colors.curpoint);
+		immUniformColor3ubv(colors.curpoint);
 		GPU_point_size(9);
 
 		immBegin(GPU_PRIM_POINTS, 1);
@@ -1137,14 +1137,14 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 		GPU_batch_program_set_builtin(batch, GPU_SHADER_3D_UNIFORM_COLOR);
 
 		/* draw any snapped verts first */
-		rgba_uchar_to_float(fcol, kcd->colors.point_a);
+		rgba_uchar_to_float(fcol, colors.point_a);
 		GPU_batch_uniform_4fv(batch, "color", fcol);
 		GPU_matrix_bind(batch->interface);
 		GPU_point_size(11);
 		GPU_batch_draw_range_ex(batch, 0, v - 1, false);
 
 		/* now draw the rest */
-		rgba_uchar_to_float(fcol, kcd->colors.curpoint_a);
+		rgba_uchar_to_float(fcol, colors.curpoint_a);
 		GPU_batch_uniform_4fv(batch, "color", fcol);
 		GPU_point_size(7);
 		GPU_batch_draw_range_ex(batch, vs + 1, kcd->totlinehit - (vs + 1), false);
@@ -1159,7 +1159,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 		BLI_mempool_iter iter;
 		KnifeEdge *kfe;
 
-		immUniformColor3ubv(kcd->colors.line);
+		immUniformColor3ubv(colors.line);
 		GPU_line_width(1.0);
 
 		GPUBatch *batch = immBeginBatchAtMost(GPU_PRIM_LINES, BLI_mempool_len(kcd->kedges) * 2);
@@ -1183,7 +1183,7 @@ static void knifetool_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void
 		BLI_mempool_iter iter;
 		KnifeVert *kfv;
 
-		immUniformColor3ubv(kcd->colors.point);
+		immUniformColor3ubv(colors.point);
 		GPU_point_size(5.0);
 
 		GPUBatch *batch = immBeginBatchAtMost(GPU_PRIM_POINTS, BLI_mempool_len(kcd->kverts));
@@ -2682,8 +2682,6 @@ static void knifetool_init(bContext *C, KnifeTool_OpData *kcd,
 
 	if (is_interactive) {
 		kcd->draw_handle = ED_region_draw_cb_activate(kcd->ar->type, knifetool_draw, kcd, REGION_DRAW_POST_VIEW);
-
-		knife_init_colors(&kcd->colors);
 	}
 }