Fix T45013 negative curve falloff not working.

Was doing clamping as fix for T42984. Seems we can ommit clamping for
sculpting if we make sure overlap is not zero with negative values.

Control for clamping is moved to the "Use Clipping" function of curves
(which is on by default), so both bugs remain squashed and advanced
users can now properly utilize curves in sculpting, though not all
brushes work well with negative curves.

9 files changed, 33 insertions, 13 deletions

diff --git a/source/blender/blenkernel/BKE_brush.h b/source/blender/blenkernel/BKE_brush.h
index 023303fe602..042fba7294c 100644
--- a/source/blender/blenkernel/BKE_brush.h
+++ b/source/blender/blenkernel/BKE_brush.h
@@ -63,6 +63,7 @@ void BKE_brush_randomize_texture_coords(struct UnifiedPaintSettings *ups, bool m
 
 /* brush curve */
 void BKE_brush_curve_preset(struct Brush *b, int preset);
+float BKE_brush_curve_strength_clamped(struct Brush *br, float p, const float len);
 float BKE_brush_curve_strength(struct Brush *br, float p, const float len);
 
 /* sampling */
diff --git a/source/blender/blenkernel/intern/brush.c b/source/blender/blenkernel/intern/brush.c
index 307f97f1344..2464b3b2668 100644
--- a/source/blender/blenkernel/intern/brush.c
+++ b/source/blender/blenkernel/intern/brush.c
@@ -971,7 +971,7 @@ void BKE_brush_randomize_texture_coords(UnifiedPaintSettings *ups, bool mask)
 	}
 }
 
-/* Uses the brush curve control to find a strength value between 0 and 1 */
+/* Uses the brush curve control to find a strength value */
 float BKE_brush_curve_strength(Brush *br, float p, const float len)
 {
 	float strength;
@@ -981,6 +981,15 @@ float BKE_brush_curve_strength(Brush *br, float p, const float len)
 
 	strength = curvemapping_evaluateF(br->curve, 0, p);
 
+	return strength;
+}
+
+
+/* Uses the brush curve control to find a strength value between 0 and 1 */
+float BKE_brush_curve_strength_clamped(Brush *br, float p, const float len)
+{
+	float strength = BKE_brush_curve_strength(br, p, len);
+
 	CLAMP(strength, 0.0f, 1.0f);
 
 	return strength;
@@ -1042,7 +1051,7 @@ struct ImBuf *BKE_brush_gen_radial_control_imbuf(Brush *br, bool secondary)
 	for (i = 0; i < side; ++i) {
 		for (j = 0; j < side; ++j) {
 			float magn = sqrtf(pow2f(i - half) + pow2f(j - half));
-			im->rect_float[i * side + j] = BKE_brush_curve_strength(br, magn, half);
+			im->rect_float[i * side + j] = BKE_brush_curve_strength_clamped(br, magn, half);
 		}
 	}
 
diff --git a/source/blender/blenkernel/intern/colortools.c b/source/blender/blenkernel/intern/colortools.c
index c5f7e12c9d0..1120034e217 100644
--- a/source/blender/blenkernel/intern/colortools.c
+++ b/source/blender/blenkernel/intern/colortools.c
@@ -790,7 +790,17 @@ float curvemap_evaluateF(const CurveMap *cuma, float value)
 float curvemapping_evaluateF(const CurveMapping *cumap, int cur, float value)
 {
 	const CurveMap *cuma = cumap->cm + cur;
-	return curvemap_evaluateF(cuma, value);
+	float val = curvemap_evaluateF(cuma, value);
+
+	/* account for clipping */
+	if (cumap->flag & CUMA_DO_CLIP) {
+		if (val < cumap->curr.ymin)
+			val = cumap->curr.ymin;
+		else if (val > cumap->curr.ymax)
+			val = cumap->curr.ymax;
+	}
+
+	return val;
 }
 
 /* vector case */
diff --git a/source/blender/editors/sculpt_paint/paint_cursor.c b/source/blender/editors/sculpt_paint/paint_cursor.c
index c88153c9836..e4cad389004 100644
--- a/source/blender/editors/sculpt_paint/paint_cursor.c
+++ b/source/blender/editors/sculpt_paint/paint_cursor.c
@@ -426,7 +426,7 @@ static int load_tex_cursor(Brush *br, ViewContext *vc, float zoom)
 				len = sqrtf(x * x + y * y);
 
 				if (len <= 1) {
-					float avg = BKE_brush_curve_strength(br, len, 1.0f);  /* Falloff curve */
+					float avg = BKE_brush_curve_strength_clamped(br, len, 1.0f);  /* Falloff curve */
 
 					buffer[index] = 255 - (GLubyte)(255 * avg);
 
diff --git a/source/blender/editors/sculpt_paint/paint_image_2d.c b/source/blender/editors/sculpt_paint/paint_image_2d.c
index 1ad700b2964..483bf0f3190 100644
--- a/source/blender/editors/sculpt_paint/paint_image_2d.c
+++ b/source/blender/editors/sculpt_paint/paint_image_2d.c
@@ -359,7 +359,7 @@ static unsigned short *brush_painter_curve_mask_new(BrushPainter *painter, int d
 			float xy[2] = {x + xoff, y + yoff};
 			float len = len_v2(xy);
 
-			*m = (unsigned short)(65535.0f * BKE_brush_curve_strength(brush, len, radius));
+			*m = (unsigned short)(65535.0f * BKE_brush_curve_strength_clamped(brush, len, radius));
 		}
 	}
 
diff --git a/source/blender/editors/sculpt_paint/paint_image_proj.c b/source/blender/editors/sculpt_paint/paint_image_proj.c
index 58f1ebb9eac..46e294de956 100644
--- a/source/blender/editors/sculpt_paint/paint_image_proj.c
+++ b/source/blender/editors/sculpt_paint/paint_image_proj.c
@@ -4722,7 +4722,7 @@ static void *do_projectpaint_thread(void *ph_v)
 				if (dist_sq <= brush_radius_sq) {
 					dist = sqrtf(dist_sq);
 
-					falloff = BKE_brush_curve_strength(ps->brush, dist, brush_radius);
+					falloff = BKE_brush_curve_strength_clamped(ps->brush, dist, brush_radius);
 
 					if (falloff > 0.0f) {
 						float texrgb[3];
diff --git a/source/blender/editors/sculpt_paint/paint_stroke.c b/source/blender/editors/sculpt_paint/paint_stroke.c
index 21beb97ffae..ece6ea7a940 100644
--- a/source/blender/editors/sculpt_paint/paint_stroke.c
+++ b/source/blender/editors/sculpt_paint/paint_stroke.c
@@ -557,7 +557,7 @@ static float paint_stroke_integrate_overlap(Brush *br, float factor)
 	g = 1.0f / m;
 	max = 0;
 	for (i = 0; i < m; i++) {
-		float overlap = paint_stroke_overlapped_curve(br, i * g, spacing);
+		float overlap = fabs(paint_stroke_overlapped_curve(br, i * g, spacing));
 
 		if (overlap > max)
 			max = overlap;
diff --git a/source/blender/editors/sculpt_paint/paint_vertex.c b/source/blender/editors/sculpt_paint/paint_vertex.c
index 1a31442faf4..5af327e7b49 100644
--- a/source/blender/editors/sculpt_paint/paint_vertex.c
+++ b/source/blender/editors/sculpt_paint/paint_vertex.c
@@ -936,7 +936,7 @@ static float calc_vp_strength_col_dl(VPaint *vp, ViewContext *vc, const float co
 			else {
 				factor = 1.0f;
 			}
-			return factor * BKE_brush_curve_strength(brush, dist, brush_size_pressure);
+			return factor * BKE_brush_curve_strength_clamped(brush, dist, brush_size_pressure);
 		}
 	}
 	if (rgba)
@@ -3217,7 +3217,7 @@ static void gradientVert_update(DMGradient_userData *grad_data, int index)
 	/* no need to clamp 'alpha' yet */
 
 	/* adjust weight */
-	alpha = BKE_brush_curve_strength(grad_data->brush, alpha, 1.0f);
+	alpha = BKE_brush_curve_strength_clamped(grad_data->brush, alpha, 1.0f);
 
 	if (alpha != 0.0f) {
 		MDeformVert *dv = &me->dvert[index];
diff --git a/source/blender/editors/sculpt_paint/sculpt_uv.c b/source/blender/editors/sculpt_paint/sculpt_uv.c
index a9feb9f48de..4e1517b4e0d 100644
--- a/source/blender/editors/sculpt_paint/sculpt_uv.c
+++ b/source/blender/editors/sculpt_paint/sculpt_uv.c
@@ -315,7 +315,7 @@ static void HC_relaxation_iteration_uv(BMEditMesh *em, UvSculptData *sculptdata,
 		if ((dist = dot_v2v2(diff, diff)) <= radius) {
 			UvElement *element;
 			float strength;
-			strength = alpha * BKE_brush_curve_strength(brush, sqrtf(dist), radius_root);
+			strength = alpha * BKE_brush_curve_strength_clamped(brush, sqrtf(dist), radius_root);
 
 			sculptdata->uv[i].uv[0] = (1.0f - strength) * sculptdata->uv[i].uv[0] + strength * (tmp_uvdata[i].p[0] - 0.5f * (tmp_uvdata[i].b[0] + tmp_uvdata[i].sum_b[0] / tmp_uvdata[i].ncounter));
 			sculptdata->uv[i].uv[1] = (1.0f - strength) * sculptdata->uv[i].uv[1] + strength * (tmp_uvdata[i].p[1] - 0.5f * (tmp_uvdata[i].b[1] + tmp_uvdata[i].sum_b[1] / tmp_uvdata[i].ncounter));
@@ -379,7 +379,7 @@ static void laplacian_relaxation_iteration_uv(BMEditMesh *em, UvSculptData *scul
 		if ((dist = dot_v2v2(diff, diff)) <= radius) {
 			UvElement *element;
 			float strength;
-			strength = alpha * BKE_brush_curve_strength(brush, sqrtf(dist), radius_root);
+			strength = alpha * BKE_brush_curve_strength_clamped(brush, sqrtf(dist), radius_root);
 
 			sculptdata->uv[i].uv[0] = (1.0f - strength) * sculptdata->uv[i].uv[0] + strength * tmp_uvdata[i].p[0];
 			sculptdata->uv[i].uv[1] = (1.0f - strength) * sculptdata->uv[i].uv[1] + strength * tmp_uvdata[i].p[1];
@@ -454,7 +454,7 @@ static void uv_sculpt_stroke_apply(bContext *C, wmOperator *op, const wmEvent *e
 			if ((dist = dot_v2v2(diff, diff)) <= radius) {
 				UvElement *element;
 				float strength;
-				strength = alpha * BKE_brush_curve_strength(brush, sqrtf(dist), radius_root);
+				strength = alpha * BKE_brush_curve_strength_clamped(brush, sqrtf(dist), radius_root);
 				normalize_v2(diff);
 
 				sculptdata->uv[i].uv[0] -= strength * diff[0] * 0.001f;
@@ -822,7 +822,7 @@ static UvSculptData *uv_sculpt_stroke_init(bContext *C, wmOperator *op, const wm
 				diff[1] /= aspectRatio;
 				if ((dist = dot_v2v2(diff, diff)) <= radius) {
 					float strength;
-					strength = alpha * BKE_brush_curve_strength(brush, sqrtf(dist), radius_root);
+					strength = alpha * BKE_brush_curve_strength_clamped(brush, sqrtf(dist), radius_root);
 
 					data->initial_stroke->initialSelection[counter].uv = i;
 					data->initial_stroke->initialSelection[counter].strength = strength;