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| 1 | +// Copyright 2013 The Flutter Authors. All rights reserved. |
| 2 | +// Use of this source code is governed by a BSD-style license that can be |
| 3 | +// found in the LICENSE file. |
| 4 | + |
| 5 | +#include "impeller/entity/geometry/ellipse_geometry.h" |
| 6 | + |
| 7 | +#include "flutter/impeller/tessellator/circle_tessellator.h" |
| 8 | + |
| 9 | +namespace impeller { |
| 10 | + |
| 11 | +EllipseGeometry::EllipseGeometry(Point center, Scalar radius) |
| 12 | + : center_(center), radius_(radius) { |
| 13 | + FML_DCHECK(radius >= 0); |
| 14 | +} |
| 15 | + |
| 16 | +GeometryResult EllipseGeometry::GetPositionBuffer( |
| 17 | + const ContentContext& renderer, |
| 18 | + const Entity& entity, |
| 19 | + RenderPass& pass) const { |
| 20 | + auto& host_buffer = pass.GetTransientsBuffer(); |
| 21 | + using VT = SolidFillVertexShader::PerVertexData; |
| 22 | + |
| 23 | + Scalar radius = radius_; |
| 24 | + const Point& center = center_; |
| 25 | + std::shared_ptr<Tessellator> tessellator = renderer.GetTessellator(); |
| 26 | + CircleTessellator circle_tessellator(tessellator, entity.GetTransform(), |
| 27 | + radius_); |
| 28 | + size_t count = circle_tessellator.GetCircleVertexCount(); |
| 29 | + auto vertex_buffer = host_buffer.Emplace( |
| 30 | + count * sizeof(VT), alignof(VT), |
| 31 | + [&circle_tessellator, ¢er, radius](uint8_t* buffer) { |
| 32 | + auto vertices = reinterpret_cast<VT*>(buffer); |
| 33 | + circle_tessellator.GenerateCircleTriangleStrip( |
| 34 | + [&vertices](const Point& p) { // |
| 35 | + *vertices++ = { |
| 36 | + .position = p, |
| 37 | + }; |
| 38 | + }, |
| 39 | + center, radius); |
| 40 | + }); |
| 41 | + |
| 42 | + return GeometryResult{ |
| 43 | + .type = PrimitiveType::kTriangleStrip, |
| 44 | + .vertex_buffer = |
| 45 | + { |
| 46 | + .vertex_buffer = vertex_buffer, |
| 47 | + .vertex_count = count, |
| 48 | + .index_type = IndexType::kNone, |
| 49 | + }, |
| 50 | + .transform = Matrix::MakeOrthographic(pass.GetRenderTargetSize()) * |
| 51 | + entity.GetTransform(), |
| 52 | + .prevent_overdraw = false, |
| 53 | + }; |
| 54 | +} |
| 55 | + |
| 56 | +// |Geometry| |
| 57 | +GeometryResult EllipseGeometry::GetPositionUVBuffer( |
| 58 | + Rect texture_coverage, |
| 59 | + Matrix effect_transform, |
| 60 | + const ContentContext& renderer, |
| 61 | + const Entity& entity, |
| 62 | + RenderPass& pass) const { |
| 63 | + auto& host_buffer = pass.GetTransientsBuffer(); |
| 64 | + using VT = TextureFillVertexShader::PerVertexData; |
| 65 | + auto uv_transform = |
| 66 | + texture_coverage.GetNormalizingTransform() * effect_transform; |
| 67 | + |
| 68 | + Scalar radius = radius_; |
| 69 | + const Point& center = center_; |
| 70 | + std::shared_ptr<Tessellator> tessellator = renderer.GetTessellator(); |
| 71 | + CircleTessellator circle_tessellator(tessellator, entity.GetTransform(), |
| 72 | + radius_); |
| 73 | + size_t count = circle_tessellator.GetCircleVertexCount(); |
| 74 | + auto vertex_buffer = host_buffer.Emplace( |
| 75 | + count * sizeof(VT), alignof(VT), |
| 76 | + [&circle_tessellator, &uv_transform, ¢er, radius](uint8_t* buffer) { |
| 77 | + auto vertices = reinterpret_cast<VT*>(buffer); |
| 78 | + circle_tessellator.GenerateCircleTriangleStrip( |
| 79 | + [&vertices, &uv_transform](const Point& p) { // |
| 80 | + *vertices++ = { |
| 81 | + .position = p, |
| 82 | + .texture_coords = uv_transform * p, |
| 83 | + }; |
| 84 | + }, |
| 85 | + center, radius); |
| 86 | + }); |
| 87 | + |
| 88 | + return GeometryResult{ |
| 89 | + .type = PrimitiveType::kTriangleStrip, |
| 90 | + .vertex_buffer = |
| 91 | + { |
| 92 | + .vertex_buffer = vertex_buffer, |
| 93 | + .vertex_count = count, |
| 94 | + .index_type = IndexType::kNone, |
| 95 | + }, |
| 96 | + .transform = Matrix::MakeOrthographic(pass.GetRenderTargetSize()) * |
| 97 | + entity.GetTransform(), |
| 98 | + .prevent_overdraw = false, |
| 99 | + }; |
| 100 | +} |
| 101 | + |
| 102 | +GeometryVertexType EllipseGeometry::GetVertexType() const { |
| 103 | + return GeometryVertexType::kPosition; |
| 104 | +} |
| 105 | + |
| 106 | +std::optional<Rect> EllipseGeometry::GetCoverage( |
| 107 | + const Matrix& transform) const { |
| 108 | + Point corners[4]{ |
| 109 | + {center_.x, center_.y - radius_}, |
| 110 | + {center_.x + radius_, center_.y}, |
| 111 | + {center_.x, center_.y + radius_}, |
| 112 | + {center_.x - radius_, center_.y}, |
| 113 | + }; |
| 114 | + |
| 115 | + for (int i = 0; i < 4; i++) { |
| 116 | + corners[i] = transform * corners[i]; |
| 117 | + } |
| 118 | + return Rect::MakePointBounds(std::begin(corners), std::end(corners)); |
| 119 | +} |
| 120 | + |
| 121 | +bool EllipseGeometry::CoversArea(const Matrix& transform, |
| 122 | + const Rect& rect) const { |
| 123 | + return false; |
| 124 | +} |
| 125 | + |
| 126 | +bool EllipseGeometry::IsAxisAlignedRect() const { |
| 127 | + return false; |
| 128 | +} |
| 129 | + |
| 130 | +} // namespace impeller |
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