linear_gradient_contents.cc File Reference

#include "linear_gradient_contents.h"
#include "impeller/core/formats.h"
#include "impeller/entity/contents/content_context.h"
#include "impeller/entity/contents/gradient_generator.h"
#include "impeller/entity/entity.h"
#include "impeller/entity/geometry/geometry.h"
#include "impeller/geometry/scalar.h"
#include "impeller/renderer/render_pass.h"
#include "impeller/renderer/vertex_buffer_builder.h"

Go to the source code of this file.

Namespaces
namespace	impeller

Macros
#define	ARRAY_LEN(a)   (sizeof(a) / sizeof(a[0]))
#define	UNIFORM_FRAG_INFO(t)    t##GradientUniformFillPipeline::FragmentShader::FragInfo
#define	UNIFORM_COLOR_SIZE   ARRAY_LEN(UNIFORM_FRAG_INFO(Linear)::colors)
#define	UNIFORM_STOP_SIZE   ARRAY_LEN(UNIFORM_FRAG_INFO(Linear)::stop_pairs)

Macro Definition Documentation

ARRAY_LEN

#define ARRAY_LEN

(

a

)

(sizeof(a) / sizeof(a[0]))

Definition at line 195 of file linear_gradient_contents.cc.

UNIFORM_COLOR_SIZE

#define UNIFORM_COLOR_SIZE   ARRAY_LEN(UNIFORM_FRAG_INFO(Linear)::colors)

Definition at line 198 of file linear_gradient_contents.cc.

UNIFORM_FRAG_INFO

#define UNIFORM_FRAG_INFO

(

t

)

t##GradientUniformFillPipeline::FragmentShader::FragInfo

Definition at line 196 of file linear_gradient_contents.cc.

                                                            {
  // TODO(148651): The fast path is overly restrictive, following the design in
  // https://github.com/flutter/flutter/issues/148651 support for more cases can
  // be gradually added.
  if (CanApplyFastGradient()) {
    return FastLinearGradient(renderer, entity, pass);
  }
  if (renderer.GetDeviceCapabilities().SupportsSSBO()) {
    return RenderSSBO(renderer, entity, pass);
  }
  if (colors_.size() <= kMaxUniformGradientStops &&
      stops_.size() <= kMaxUniformGradientStops) {
    return RenderUniform(renderer, entity, pass);
  }
  return RenderTexture(renderer, entity, pass);
}
 
bool LinearGradientContents::RenderTexture(const ContentContext& renderer,
                                           const Entity& entity,
                                           RenderPass& pass) const {
  using VS = LinearGradientFillPipeline::VertexShader;
  using FS = LinearGradientFillPipeline::FragmentShader;
 
  VS::FrameInfo frame_info;
  frame_info.matrix = GetInverseEffectTransform();
 
  PipelineBuilderCallback pipeline_callback =
      [&renderer](ContentContextOptions options) {
        return renderer.GetLinearGradientFillPipeline(options);
      };
  return ColorSourceContents::DrawGeometry<VS>(
      renderer, entity, pass, pipeline_callback, frame_info,
      [this, &renderer, &entity](RenderPass& pass) {
        auto gradient_data = CreateGradientBuffer(colors_, stops_);
        auto gradient_texture =
            CreateGradientTexture(gradient_data, renderer.GetContext());
        if (gradient_texture == nullptr) {
          return false;
        }
 
        FS::FragInfo frag_info;
        frag_info.start_point = start_point_;
        frag_info.end_point = end_point_;
        frag_info.tile_mode = static_cast<Scalar>(tile_mode_);
        frag_info.decal_border_color = decal_border_color_;
        frag_info.texture_sampler_y_coord_scale =
            gradient_texture->GetYCoordScale();
        frag_info.alpha =
            GetOpacityFactor() *
            GetGeometry()->ComputeAlphaCoverage(entity.GetTransform());
        ;
        frag_info.half_texel =
            Vector2(0.5 / gradient_texture->GetSize().width,
                    0.5 / gradient_texture->GetSize().height);
 
        pass.SetCommandLabel("LinearGradientFill");
 
        SamplerDescriptor sampler_desc;
        sampler_desc.min_filter = MinMagFilter::kLinear;
        sampler_desc.mag_filter = MinMagFilter::kLinear;
 
        FS::BindTextureSampler(
            pass, std::move(gradient_texture),
            renderer.GetContext()->GetSamplerLibrary()->GetSampler(
                sampler_desc));
        FS::BindFragInfo(
            pass, renderer.GetTransientsDataBuffer().EmplaceUniform(frag_info));
        return true;
      });
}
 
namespace {
Scalar CalculateInverseDotStartToEnd(Point start_point, Point end_point) {
  Point start_to_end = end_point - start_point;
  Scalar dot =
      (start_to_end.x * start_to_end.x + start_to_end.y * start_to_end.y);
  return dot == 0.0f ? 0.0f : 1.0f / dot;
}
}  // namespace
 
bool LinearGradientContents::RenderSSBO(const ContentContext& renderer,
                                        const Entity& entity,
                                        RenderPass& pass) const {
  using VS = LinearGradientSSBOFillPipeline::VertexShader;
  using FS = LinearGradientSSBOFillPipeline::FragmentShader;
 
  VS::FrameInfo frame_info;
  frame_info.matrix = GetInverseEffectTransform();
 
  PipelineBuilderCallback pipeline_callback =
      [&renderer](ContentContextOptions options) {
        return renderer.GetLinearGradientSSBOFillPipeline(options);
      };
  return ColorSourceContents::DrawGeometry<VS>(
      renderer, entity, pass, pipeline_callback, frame_info,
      [this, &renderer, &entity](RenderPass& pass) {
        FS::FragInfo frag_info;
        frag_info.start_point = start_point_;
        frag_info.end_point = end_point_;
        frag_info.tile_mode = static_cast<Scalar>(tile_mode_);
        frag_info.decal_border_color = decal_border_color_;
        frag_info.alpha =
            GetOpacityFactor() *
            GetGeometry()->ComputeAlphaCoverage(entity.GetTransform());
        frag_info.start_to_end = end_point_ - start_point_;
        frag_info.inverse_dot_start_to_end =
            CalculateInverseDotStartToEnd(start_point_, end_point_);
 
        auto& data_host_buffer = renderer.GetTransientsDataBuffer();
        auto colors = CreateGradientColors(colors_, stops_);
 
        frag_info.colors_length = colors.size();
        auto color_buffer = data_host_buffer.Emplace(
            colors.data(), colors.size() * sizeof(StopData),
            renderer.GetDeviceCapabilities()
                .GetMinimumStorageBufferAlignment());
 
        pass.SetCommandLabel("LinearGradientSSBOFill");
 
        FS::BindFragInfo(pass, data_host_buffer.EmplaceUniform(frag_info));
        FS::BindColorData(pass, color_buffer);
 
        return true;
      });
}
 
bool LinearGradientContents::RenderUniform(const ContentContext& renderer,
                                           const Entity& entity,
                                           RenderPass& pass) const {
  using VS = LinearGradientUniformFillPipeline::VertexShader;
  using FS = LinearGradientUniformFillPipeline::FragmentShader;
 
  VS::FrameInfo frame_info;
  frame_info.matrix = GetInverseEffectTransform();
 
  PipelineBuilderCallback pipeline_callback =
      [&renderer](ContentContextOptions options) {
        return renderer.GetLinearGradientUniformFillPipeline(options);
      };
  return ColorSourceContents::DrawGeometry<VS>(
      renderer, entity, pass, pipeline_callback, frame_info,
      [this, &renderer, &entity](RenderPass& pass) {
        FS::FragInfo frag_info;
        frag_info.start_point = start_point_;
        frag_info.start_to_end = end_point_ - start_point_;
        frag_info.alpha =
            GetOpacityFactor() *
            GetGeometry()->ComputeAlphaCoverage(entity.GetTransform());
        frag_info.tile_mode = static_cast<Scalar>(tile_mode_);
        frag_info.colors_length = PopulateUniformGradientColors(
            colors_, stops_, frag_info.colors, frag_info.stop_pairs);
        frag_info.inverse_dot_start_to_end =
            CalculateInverseDotStartToEnd(start_point_, end_point_);
        frag_info.decal_border_color = decal_border_color_;
 
        pass.SetCommandLabel("LinearGradientUniformFill");
 
        FS::BindFragInfo(
            pass, renderer.GetTransientsDataBuffer().EmplaceUniform(frag_info));
 
        return true;
      });
}
 
bool LinearGradientContents::ApplyColorFilter(
    const ColorFilterProc& color_filter_proc) {
  for (Color& color : colors_) {
    color = color_filter_proc(color);
  }
  decal_border_color_ = color_filter_proc(decal_border_color_);
  return true;
}
 
}  // namespace impeller

UNIFORM_STOP_SIZE

#define UNIFORM_STOP_SIZE   ARRAY_LEN(UNIFORM_FRAG_INFO(Linear)::stop_pairs)

Definition at line 199 of file linear_gradient_contents.cc.