GPv3: Fill textures coordinates

@@ -868,0 +878,4 @@
+ */
+void set_texture_matrix(blender::bke::greasepencil::Drawing &drawing,
+                        int curve_i,
+                        const blender::float4x2);

@@ -868,0 +885,4 @@
+ */
+void transfer_texture_matrices(const blender::bke::greasepencil::Drawing &src,
+                               blender::bke::greasepencil::Drawing &dst,
+                               const blender::Span<int> dst_to_src_curve);

@@ -868,0 +887,4 @@
+                               blender::bke::greasepencil::Drawing &dst,
+                               const blender::Span<int> dst_to_src_curve);
+void transfer_texture_matrices(const blender::bke::greasepencil::Drawing &src,
+                               blender::bke::greasepencil::Drawing &dst,

@@ -1461,0 +1473,4 @@
+  using namespace blender::math;
+
+  const bke::CurvesGeometry &curves = drawing.strokes();
+  const offset_indices::OffsetIndices<int> points_by_curve = curves.points_by_curve();

@@ -1461,0 +1483,4 @@
+    return float4x2::identity();
+  }
+
+  const float3 pt0 = positions[points.first()];

@@ -1461,0 +1489,4 @@
+  /* Local X axis (p0 -> p1) */
+  const float3 locx = normalize(pt1 - pt0);
+  /* Local Y axis (cross to normal/x axis). */
+  const float3 locy = normalize(cross(normal, locx));

@@ -1461,0 +1544,4 @@
+   */
+
+  /* Apply scale. */
+  textmat = from_scale<float2x2>(uv_scale_inv) * textmat;

@@ -1461,0 +1693,4 @@
+                               blender::bke::greasepencil::Drawing &dst,
+                               const blender::IndexMask &dst_to_src_curve)
+{
+  dst_to_src_curve.foreach_index([&](const int64_t index, const int64_t pos) {

@@ -868,0 +869,4 @@
+ * Returns the matrix that transforms from a 3D point in layer-space to a 2D point in
+ * texture-space for the stroke `curve_i`
+ */
+blender::float4x2 get_texture_matrix(const blender::bke::greasepencil::Drawing &drawing,

@@ -868,0 +876,4 @@
+ * Sets the matrix the that transforms from a 3D point in layer-space to a 2D point in
+ * texture-space for the stroke `curve_i`
+ */
+void set_texture_matrix(blender::bke::greasepencil::Drawing &drawing,

@@ -868,0 +883,4 @@
+/*
+ * Copy the texture matrices from `src` to `dst` for the strokes in `dst_to_src_curve`
+ */
+void transfer_texture_matrices(const blender::bke::greasepencil::Drawing &src,

@@ -1461,0 +1605,4 @@
+  using namespace blender;
+
+  const float4x2 strokemat = get_local_to_stroke_matrix(drawing, curve_i);
+  const float3x2 textmat = get_stroke_to_texture_matrix(drawing.strokes(), curve_i);

@@ -1461,0 +1662,4 @@
+   * Our problem has the form of: `X = A * Y`
+   * We can solve for `A` using: `A = X * B`
+   *
+   * Where `B` is the Right-sided inverse, calculated as:

@@ -415,0 +536,4 @@
+  return this->runtime->curve_texture_matrices.data().as_span();
+}
+
+static void set_stroke_to_texture_matrix(CurvesGeometry &curves, int curve_i, float3x2 texmat)

@@ -415,0 +585,4 @@
+    const float4x2 texspace = matrices[pos];
+
+    /*
+     * WORKAROUND: This algorithm could work with floats but is prone to numerical error.

@@ -159,0 +172,4 @@
+  const float2 center = float2(0.5f, 0.5f);
+
+  const float2 uv_scale_inv = math::safe_rcp(uv_scale);
+  const float2 d = maxv - minv;

@@ -159,0 +173,4 @@
+
+  const float2 uv_scale_inv = math::safe_rcp(uv_scale);
+  const float2 d = maxv - minv;
+  const float s = sin(uv_rotation);

@@ -159,0 +175,4 @@
+  const float2 d = maxv - minv;
+  const float s = sin(uv_rotation);
+  const float c = cos(uv_rotation);
+  const float2x2 rot = float2x2(float2(c, s), float2(-s, c));

@@ -159,0 +177,4 @@
+  const float c = cos(uv_rotation);
+  const float2x2 rot = float2x2(float2(c, s), float2(-s, c));
+
+  float3x2 texmat = float3x2::identity();

@@ -418,0 +479,4 @@
+  const float c = cos(uv_rotation);
+  const float2x2 rot = float2x2(float2(c, s), float2(-s, c));
+
+  float3x2 texmat = float3x2::identity();

@@ -159,0 +222,4 @@
+  const float3 pt3 = float3(point3->x, point3->y, point3->z);
+
+  /* Local X axis (p0 -> p1) */
+  const float3 locx = normalize(pt1 - pt0);

@@ -159,0 +226,4 @@
+
+  /* Point vector at 3/4 */
+  const float3 v3 = totpoints == 2 ? pt3 * 0.001f : pt3;
+  const float3 loc3 = v3 - pt0;

@@ -418,0 +463,4 @@
+  using namespace blender::math;
+  const AttributeAccessor attributes = curves.attributes();
+
+  const VArray<float> uv_rotations = *attributes.lookup_or_default<float>(

@@ -418,0 +481,4 @@
+
+  float3x2 texmat = float3x2::identity();
+  /*
+   * The order in which the three transforms are applied, has been carefully chosen to be easy to

@@ -418,0 +547,4 @@
+  SpanAttributeWriter<float> uv_rotations = attributes.lookup_or_add_for_write_span<float>(
+      "uv_rotation",
+      AttrDomain::Curve,
+      AttributeInitVArray(VArray<float>::ForSingle(0.0f, curves.curves_num())));

@@ -418,0 +557,4 @@
+      AttrDomain::Curve,
+      AttributeInitVArray(VArray<float2>::ForSingle(float2(1.0f, 1.0f), curves.curves_num())));
+
+  auto set_stroke_to_texture_matrix = [&](int curve_i, float3x2 texmat) {

@@ -418,0 +589,4 @@
+     *
+     * i.e.
+     *          # # # #              # # # #
+     * We need  # # # #  Instead of  # # # #

@@ -370,0 +468,4 @@
+
+    const float4x2 legacy_texture_matrix = get_legacy_texture_matrix(gps);
+    /* Ensure that everything is up to date. */
+    drawing.tag_positions_changed();

@@ -553,10 +555,11 @@ static void grease_pencil_geom_batch_ensure(Object &object,
                               int point_i,
                               int idx,
                               float length,
+                              float4x2 texture_matrix,

@@ -486,1 +491,4 @@
 
+  float3 u_dir;
+  float3 v_dir;
+  float3 origin = float3(0.0f);

@@ -74,2 +77,4 @@
   void tag_topology_changed();
 
+  /*
+   * Returns the matrices that transforms from a 3D point in layer-space to a 2D point in

@@ -76,0 +82,4 @@
+   */
+  Span<float4x2> texture_matrices() const;
+  /*
+   * Sets the matrices the that transforms from a 3D point in layer-space to a 2D point in

@@ -429,0 +436,4 @@
+  using namespace blender::math;
+
+  const CurvesGeometry &curves = drawing.strokes();
+  const OffsetIndices<int> points_by_curve = curves.points_by_curve();

@@ -429,0 +568,4 @@
+      AttrDomain::Curve,
+      AttributeInitVArray(VArray<float2>::ForSingle(float2(1.0f, 1.0f), curves.curves_num())));
+
+  selection.foreach_index([&](const int64_t curve_i, const int64_t pos) {