Skip to content

Commit

Permalink
[Impeller] Add Rect::GetNormalizingTransform to handle UV coordinate …
Browse files Browse the repository at this point in the history 
…conversion
  • Loading branch information
@flar
flar committed Nov 8, 2023
1 parent a1bad07 commit 23e60b7
Show file tree
Hide file tree
Showing 5 changed files with 185 additions and 20 deletions.
13 changes: 6 additions & 7 deletions impeller/entity/geometry/fill_path_geometry.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,9 @@ GeometryResult FillPathGeometry::GetPositionUVBuffer(
RenderPass& pass) {
using VS = TextureFillVertexShader;

auto uv_transform =
effect_transform * texture_coverage.GetNormalizingTransform();

if (path_.GetFillType() == FillType::kNonZero && //
path_.IsConvex()) {
auto [points, indices] = TessellateConvex(
Expand All @@ -93,9 +96,7 @@ GeometryResult FillPathGeometry::GetPositionUVBuffer(
for (auto i = 0u; i < points.size(); i++) {
VS::PerVertexData data;
data.position = points[i];
data.texture_coords = effect_transform *
(points[i] - texture_coverage.origin) /
texture_coverage.size;
data.texture_coords = uv_transform * points[i];
vertex_builder.AppendVertex(data);
}
for (auto i = 0u; i < indices.size(); i++) {
Expand All @@ -116,16 +117,14 @@ GeometryResult FillPathGeometry::GetPositionUVBuffer(
auto tesselation_result = renderer.GetTessellator()->Tessellate(
path_.GetFillType(),
path_.CreatePolyline(entity.GetTransformation().GetMaxBasisLength()),
[&vertex_builder, &texture_coverage, &effect_transform](
[&vertex_builder, &uv_transform](
const float* vertices, size_t vertices_count, const uint16_t* indices,
size_t indices_count) {
for (auto i = 0u; i < vertices_count * 2; i += 2) {
VS::PerVertexData data;
Point vtx = {vertices[i], vertices[i + 1]};
data.position = vtx;
data.texture_coords = effect_transform *
(vtx - texture_coverage.origin) /
texture_coverage.size;
data.texture_coords = uv_transform * vtx;
vertex_builder.AppendVertex(data);
}
FML_DCHECK(vertex_builder.GetVertexCount() == vertices_count);
Expand Down
5 changes: 3 additions & 2 deletions impeller/entity/geometry/geometry.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -75,12 +75,13 @@ GeometryResult ComputeUVGeometryForRect(Rect source_rect,
RenderPass& pass) {
auto& host_buffer = pass.GetTransientsBuffer();

auto uv_transform =
effect_transform * texture_coverage.GetNormalizingTransform();
std::vector<Point> data(8);
auto points = source_rect.GetPoints();
for (auto i = 0u, j = 0u; i < 8; i += 2, j++) {
data[i] = points[j];
data[i + 1] = effect_transform * (points[j] - texture_coverage.origin) /
texture_coverage.size;
data[i + 1] = uv_transform * points[j];
}

return GeometryResult{
Expand Down
8 changes: 3 additions & 5 deletions impeller/entity/geometry/vertices_geometry.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -227,18 +227,16 @@ GeometryResult VerticesGeometry::GetPositionUVBuffer(

auto index_count = indices_.size();
auto vertex_count = vertices_.size();
auto size = texture_coverage.size;
auto origin = texture_coverage.origin;
auto uv_transform =
effect_transform * texture_coverage.GetNormalizingTransform();
auto has_texture_coordinates = HasTextureCoordinates();
std::vector<VS::PerVertexData> vertex_data(vertex_count);
{
for (auto i = 0u; i < vertex_count; i++) {
auto vertex = vertices_[i];
auto texture_coord =
has_texture_coordinates ? texture_coordinates_[i] : vertices_[i];
auto uv =
effect_transform * Point((texture_coord.x - origin.x) / size.width,
(texture_coord.y - origin.y) / size.height);
auto uv = uv_transform * texture_coord;
// From experimentation we need to clamp these values to < 1.0 or else
// there can be flickering.
vertex_data[i] = {
Expand Down
29 changes: 29 additions & 0 deletions impeller/geometry/rect.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -214,6 +214,35 @@ struct TRect {
return TRect::MakePointBounds(points.begin(), points.end()).value();
}

/// @brief Constructs a Matrix that will map all points in the coordinate
/// space of the rectangle into a new normalized coordinate space
/// where the upper left corner of the rectangle maps to (0, 0)
/// and the lower right corner of the rectangle maps to (1, 1).
///
/// Empty and non-finite rectangles will return a zero-scaling
/// transform that maps all points to (0, 0).
constexpr Matrix GetNormalizingTransform() const {
if (!IsEmpty()) {
Scalar sx = 1.0 / size.width;
Scalar sy = 1.0 / size.height;
Scalar tx = origin.x * -sx;
Scalar ty = origin.y * -sy;

// Exclude NaN and infinities and either scale underflowing to zero
if (sx != 0.0 && sy != 0.0 && 0.0 * sx * sy * tx * ty == 0.0) {
// clang-format off
return Matrix( sx, 0.0f, 0.0f, 0.0f,
0.0f, sy, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
tx, ty, 0.0f, 1.0f);
// clang-format on
}
}

// Map all coordinates to the origin.
return Matrix::MakeScale({0.0f, 0.0f, 1.0f});
}

constexpr TRect Union(const TRect& o) const {
auto this_ltrb = GetLTRB();
auto other_ltrb = o.GetLTRB();
Expand Down
150 changes: 144 additions & 6 deletions impeller/geometry/rect_unittests.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,14 +14,14 @@ namespace testing {
TEST(RectTest, RectOriginSizeGetters) {
{
Rect r = Rect::MakeOriginSize({10, 20}, {50, 40});
ASSERT_EQ(r.GetOrigin(), Point(10, 20));
ASSERT_EQ(r.GetSize(), Size(50, 40));
EXPECT_EQ(r.GetOrigin(), Point(10, 20));
EXPECT_EQ(r.GetSize(), Size(50, 40));
}

{
Rect r = Rect::MakeLTRB(10, 20, 50, 40);
ASSERT_EQ(r.GetOrigin(), Point(10, 20));
ASSERT_EQ(r.GetSize(), Size(40, 20));
EXPECT_EQ(r.GetOrigin(), Point(10, 20));
EXPECT_EQ(r.GetSize(), Size(40, 20));
}
}

Expand All @@ -44,14 +44,152 @@ TEST(RectTest, RectMakeSize) {
Size s(100, 200);
IRect r = IRect::MakeSize(s);
IRect expected = IRect::MakeLTRB(0, 0, 100, 200);
ASSERT_EQ(r, expected);
EXPECT_EQ(r, expected);
}

{
ISize s(100, 200);
IRect r = IRect::MakeSize(s);
IRect expected = IRect::MakeLTRB(0, 0, 100, 200);
ASSERT_EQ(r, expected);
EXPECT_EQ(r, expected);
}
}

TEST(RectTest, RectGetNormalizingTransform) {
{
// Checks for expected matrix values

auto r = Rect::MakeXYWH(100, 200, 200, 400);

EXPECT_EQ(r.GetNormalizingTransform(),
Matrix::MakeScale({0.005, 0.0025, 1.0}) *
Matrix::MakeTranslation({-100, -200}));
}

{
// Checks for expected transformation of points relative to the rect

auto r = Rect::MakeLTRB(300, 500, 400, 700);
auto m = r.GetNormalizingTransform();

// The 4 corners of the rect => (0, 0) to (1, 1)
EXPECT_EQ(m * Point(300, 500), Point(0, 0));
EXPECT_EQ(m * Point(400, 500), Point(1, 0));
EXPECT_EQ(m * Point(400, 700), Point(1, 1));
EXPECT_EQ(m * Point(300, 700), Point(0, 1));

// The center => (0.5, 0.5)
EXPECT_EQ(m * Point(350, 600), Point(0.5, 0.5));

// Outside the 4 corners => (-1, -1) to (2, 2)
EXPECT_EQ(m * Point(200, 300), Point(-1, -1));
EXPECT_EQ(m * Point(500, 300), Point(2, -1));
EXPECT_EQ(m * Point(500, 900), Point(2, 2));
EXPECT_EQ(m * Point(200, 900), Point(-1, 2));
}

{
// Checks for behavior with empty rects

auto zero = Matrix::MakeScale({0.0, 0.0, 1.0});

// Empty for width and/or height == 0
EXPECT_EQ(Rect::MakeXYWH(10, 10, 0, 10).GetNormalizingTransform(), zero);
EXPECT_EQ(Rect::MakeXYWH(10, 10, 10, 0).GetNormalizingTransform(), zero);
EXPECT_EQ(Rect::MakeXYWH(10, 10, 0, 0).GetNormalizingTransform(), zero);

// Empty for width and/or height < 0
EXPECT_EQ(Rect::MakeXYWH(10, 10, -1, 10).GetNormalizingTransform(), zero);
EXPECT_EQ(Rect::MakeXYWH(10, 10, 10, -1).GetNormalizingTransform(), zero);
EXPECT_EQ(Rect::MakeXYWH(10, 10, -1, -1).GetNormalizingTransform(), zero);
}

{
// Checks for behavior with non-finite rects

auto z = Matrix::MakeScale({0.0, 0.0, 1.0});
auto nan = std::numeric_limits<Scalar>::quiet_NaN();
auto inf = std::numeric_limits<Scalar>::infinity();

// Non-finite for width and/or height == nan
EXPECT_EQ(Rect::MakeXYWH(10, 10, nan, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, 10, 10, nan).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, 10, nan, nan).GetNormalizingTransform(), z);

// Non-finite for width and/or height == inf
EXPECT_EQ(Rect::MakeXYWH(10, 10, inf, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, 10, 10, inf).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, 10, inf, inf).GetNormalizingTransform(), z);

// Non-finite for width and/or height == -inf
EXPECT_EQ(Rect::MakeXYWH(10, 10, -inf, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, 10, 10, -inf).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, 10, -inf, -inf).GetNormalizingTransform(), z);

// Non-finite for origin X and/or Y == nan
EXPECT_EQ(Rect::MakeXYWH(nan, 10, 10, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, nan, 10, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(nan, nan, 10, 10).GetNormalizingTransform(), z);

// Non-finite for origin X and/or Y == inf
EXPECT_EQ(Rect::MakeXYWH(inf, 10, 10, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, inf, 10, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(inf, inf, 10, 10).GetNormalizingTransform(), z);

// Non-finite for origin X and/or Y == -inf
EXPECT_EQ(Rect::MakeXYWH(-inf, 10, 10, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(10, -inf, 10, 10).GetNormalizingTransform(), z);
EXPECT_EQ(Rect::MakeXYWH(-inf, -inf, 10, 10).GetNormalizingTransform(), z);
}
}

TEST(RectTest, IRectGetNormalizingTransform) {
{
// Checks for expected matrix values

auto r = IRect::MakeXYWH(100, 200, 200, 400);

EXPECT_EQ(r.GetNormalizingTransform(),
Matrix::MakeScale({0.005, 0.0025, 1.0}) *
Matrix::MakeTranslation({-100, -200}));
}

{
// Checks for expected transformation of points relative to the rect

auto r = IRect::MakeLTRB(300, 500, 400, 700);
auto m = r.GetNormalizingTransform();

// The 4 corners of the rect => (0, 0) to (1, 1)
EXPECT_EQ(m * Point(300, 500), Point(0, 0));
EXPECT_EQ(m * Point(400, 500), Point(1, 0));
EXPECT_EQ(m * Point(400, 700), Point(1, 1));
EXPECT_EQ(m * Point(300, 700), Point(0, 1));

// The center => (0.5, 0.5)
EXPECT_EQ(m * Point(350, 600), Point(0.5, 0.5));

// Outside the 4 corners => (-1, -1) to (2, 2)
EXPECT_EQ(m * Point(200, 300), Point(-1, -1));
EXPECT_EQ(m * Point(500, 300), Point(2, -1));
EXPECT_EQ(m * Point(500, 900), Point(2, 2));
EXPECT_EQ(m * Point(200, 900), Point(-1, 2));
}

{
// Checks for behavior with empty rects

auto zero = Matrix::MakeScale({0.0, 0.0, 1.0});

// Empty for width and/or height == 0
EXPECT_EQ(IRect::MakeXYWH(10, 10, 0, 10).GetNormalizingTransform(), zero);
EXPECT_EQ(IRect::MakeXYWH(10, 10, 10, 0).GetNormalizingTransform(), zero);
EXPECT_EQ(IRect::MakeXYWH(10, 10, 0, 0).GetNormalizingTransform(), zero);

// Empty for width and/or height < 0
EXPECT_EQ(IRect::MakeXYWH(10, 10, -1, 10).GetNormalizingTransform(), zero);
EXPECT_EQ(IRect::MakeXYWH(10, 10, 10, -1).GetNormalizingTransform(), zero);
EXPECT_EQ(IRect::MakeXYWH(10, 10, -1, -1).GetNormalizingTransform(), zero);
}
}

Expand Down

0 comments on commit 23e60b7

Please sign in to comment.