Fix T40020: Freestyle: dashed lines crashes blender.

The crash was due to an out-of-range vertex index reference that occured while
computing texture coordinates of strokes with tips.

1 files changed, 61 insertions, 56 deletions

diff --git a/source/blender/freestyle/intern/stroke/StrokeRep.cpp b/source/blender/freestyle/intern/stroke/StrokeRep.cpp
index 4cfdd860d20..4eee050c689 100644
--- a/source/blender/freestyle/intern/stroke/StrokeRep.cpp
+++ b/source/blender/freestyle/intern/stroke/StrokeRep.cpp
@@ -552,35 +552,37 @@ void Strip::computeTexCoordWithTips (const vector<StrokeVertex*>& iStrokeVertice
 			uPrev = u;
 		}
 
-		// first transition vertex
-		if (fabs(u - uPrev) > ZERO)
-			t = (0.25 - uPrev) / (u - uPrev);
-		else
-			t = 0;
-		for (int k = 0; k < 2; k++) {
-			tvRep[k] = new StrokeVertexRep((1 - t) * _vertices[i - 2]->point2d() + t * _vertices[i]->point2d());
-			tvRep[k]->setTexCoord((1 - t) * _vertices[i - 2]->texCoord() + t * _vertices[i]->texCoord());
-			// v coord is 0.5 for tvRep[0], 1.0 for tvRep[1]
-			tvRep[k]->setTexCoord(Vec2r(0.25, 0.5 * (k + 1)), true);
-			tvRep[k]->setColor((1 - t) * _vertices[i - 2]->color() + t * Vec3r(sv->attribute().getColorRGB()));
-			tvRep[k]->setAlpha((1 - t) * _vertices[i - 2]->alpha() + t * sv->attribute().getAlpha());
-			i++;
-		}
-		for (int k = 0; k < 2; k++) {
-			currentSV = _vertices.insert(currentSV, tvRep[k]);
-			++currentSV;
-		}
+		if (i >= 2) {
+			// first transition vertex
+			if (fabs(u - uPrev) > ZERO)
+				t = (0.25 - uPrev) / (u - uPrev);
+			else
+				t = 0;
+			for (int k = 0; k < 2; k++) {
+				tvRep[k] = new StrokeVertexRep((1 - t) * _vertices[i - 2]->point2d() + t * _vertices[i]->point2d());
+				tvRep[k]->setTexCoord((1 - t) * _vertices[i - 2]->texCoord() + t * _vertices[i]->texCoord());
+				// v coord is 0.5 for tvRep[0], 1.0 for tvRep[1]
+				tvRep[k]->setTexCoord(Vec2r(0.25, 0.5 * (k + 1)), true);
+				tvRep[k]->setColor((1 - t) * _vertices[i - 2]->color() + t * Vec3r(sv->attribute().getColorRGB()));
+				tvRep[k]->setAlpha((1 - t) * _vertices[i - 2]->alpha() + t * sv->attribute().getAlpha());
+				i++;
+			}
+			for (int k = 0; k < 2; k++) {
+				currentSV = _vertices.insert(currentSV, tvRep[k]);
+				++currentSV;
+			}
 
-		// copy the vertices with different texture coordinates
-		for (int k = 0; k < 2; k++) {
-			tvRep[k] = new StrokeVertexRep(*(_vertices[i - 2]));
-			// v coord is 0.0 for tvRep[0], 0.5 for tvRep[1]
-			tvRep[k]->setTexCoord(Vec2r(0.0, 0.5 * k), true); // FIXED u coord
-			i++;
-		}
-		for (int k = 0; k < 2; k++) {
-			currentSV = _vertices.insert(currentSV, tvRep[k]);
-			++currentSV;
+			// copy the vertices with different texture coordinates
+			for (int k = 0; k < 2; k++) {
+				tvRep[k] = new StrokeVertexRep(*(_vertices[i - 2]));
+				// v coord is 0.0 for tvRep[0], 0.5 for tvRep[1]
+				tvRep[k]->setTexCoord(Vec2r(0.0, 0.5 * k), true); // FIXED u coord
+				i++;
+			}
+			for (int k = 0; k < 2; k++) {
+				currentSV = _vertices.insert(currentSV, tvRep[k]);
+				++currentSV;
+			}
 		}
 	}
 	uPrev = 0;
@@ -604,36 +606,39 @@ void Strip::computeTexCoordWithTips (const vector<StrokeVertex*>& iStrokeVertice
 
 		uPrev = u;
 	}
+
 	if (tipEnd) {
-		// second transition vertex
-		if (fabs(u - uPrev) > ZERO)
-			t = (float(tiles) - uPrev) / (u - uPrev);
-		else
-			t = 0;
-		for (int k = 0; k < 2; k++) {
-			tvRep[k] = new StrokeVertexRep((1 - t) * _vertices[i - 2]->point2d() + t * _vertices[i]->point2d());
-			tvRep[k]->setTexCoord((1 - t) * _vertices[i - 2]->texCoord() + t * _vertices[i]->texCoord());
-			// v coord is 0.0 for tvRep[0], 0.5 for tvRep[1]
-			tvRep[k]->setTexCoord(Vec2r((real)tiles, 0.5 * k), true); // FIXED u coord
-			tvRep[k]->setColor((1 - t) * _vertices[i - 2]->color() + t * Vec3r(sv->attribute().getColorRGB()));
-			tvRep[k]->setAlpha((1 - t) * _vertices[i - 2]->alpha() + t * sv->attribute().getAlpha());
-			i++;
-		}
-		for (int k = 0; k < 2; k++) {
-			currentSV = _vertices.insert(currentSV, tvRep[k]);
-			++currentSV;
-		}
+		if (i >= 2) {
+			// second transition vertex
+			if (fabs(u - uPrev) > ZERO)
+				t = (float(tiles) - uPrev) / (u - uPrev);
+			else
+				t = 0;
+			for (int k = 0; k < 2; k++) {
+				tvRep[k] = new StrokeVertexRep((1 - t) * _vertices[i - 2]->point2d() + t * _vertices[i]->point2d());
+				tvRep[k]->setTexCoord((1 - t) * _vertices[i - 2]->texCoord() + t * _vertices[i]->texCoord());
+				// v coord is 0.0 for tvRep[0], 0.5 for tvRep[1]
+				tvRep[k]->setTexCoord(Vec2r((real)tiles, 0.5 * k), true); // FIXED u coord
+				tvRep[k]->setColor((1 - t) * _vertices[i - 2]->color() + t * Vec3r(sv->attribute().getColorRGB()));
+				tvRep[k]->setAlpha((1 - t) * _vertices[i - 2]->alpha() + t * sv->attribute().getAlpha());
+				i++;
+			}
+			for (int k = 0; k < 2; k++) {
+				currentSV = _vertices.insert(currentSV, tvRep[k]);
+				++currentSV;
+			}
 
-		// copy the vertices with different texture coordinates
-		for (int k = 0; k < 2; k++) {
-			tvRep[k] = new StrokeVertexRep(*(_vertices[i - 2]));
-			// v coord is 0.5 for tvRep[0], 1.0 for tvRep[1]
-			tvRep[k]->setTexCoord(Vec2r(0.75, 0.5 * (k + 1)), true);
-			i++;
-		}
-		for (int k = 0; k < 2; k++) {
-			currentSV = _vertices.insert(currentSV, tvRep[k]);
-			++currentSV;
+			// copy the vertices with different texture coordinates
+			for (int k = 0; k < 2; k++) {
+				tvRep[k] = new StrokeVertexRep(*(_vertices[i - 2]));
+				// v coord is 0.5 for tvRep[0], 1.0 for tvRep[1]
+				tvRep[k]->setTexCoord(Vec2r(0.75, 0.5 * (k + 1)), true);
+				i++;
+			}
+			for (int k = 0; k < 2; k++) {
+				currentSV = _vertices.insert(currentSV, tvRep[k]);
+				++currentSV;
+			}
 		}
 
 		// end tip