| Flutter Impeller |

Public Member Functions | List of all members
impeller::EntityPassTarget Class Reference

`#include <entity_pass_target.h>`

## Public Member Functions
| EntityPassTarget (const RenderTarget &render_target, bool supports_read_from_resolve, bool supports_implicit_msaa)
std::shared_ptr< Texture > | Flip (Allocator &allocator)
| Flips the backdrop and returns a readable texture that can be bound/sampled to restore the previous pass. More...
const RenderTarget & | GetRenderTarget () const
bool | IsValid () const

## Detailed Description

Definition at line 15 of file entity_pass_target.h.

## Constructor & Destructor Documentation

## ◆ EntityPassTarget()

impeller::EntityPassTarget::EntityPassTarget | ( | const RenderTarget & | render_target,
|  | bool | supports_read_from_resolve,
|  | bool | supports_implicit_msaa
| ) |  |
| explicit

Definition at line 13 of file entity_pass_target.cc.

16 : target_(render_target),
17 supports_read_from_resolve_(supports_read_from_resolve),
18 supports_implicit_msaa_(supports_implicit_msaa) {}

## Member Function Documentation

## ◆ Flip()

std::shared_ptr< Texture > impeller::EntityPassTarget::Flip | ( | Allocator & | allocator | ) |

Flips the backdrop and returns a readable texture that can be bound/sampled to restore the previous pass.

After this method is called, a new `RenderPass` that attaches the result of `GetRenderTarget` is guaranteed to be able to read the previous pass's backdrop texture (which is returned by this method).

Definition at line 20 of file entity_pass_target.cc.

20 {
21 auto color0 = target_.GetColorAttachments().find(0)->second;
22 if (!color0.resolve_texture) {
23 VALIDATION_LOG << "EntityPassTarget Flip should never be called for a "
24 "non-MSAA target.";
25 // ...because there is never a circumstance where doing so would be
26 // necessary. Unlike MSAA passes, non-MSAA passes can be trivially loaded
27 // with `LoadAction::kLoad`.
28 return color0.texture;
29 }
30
31 if (supports_read_from_resolve_) {
32 // Just return the current resolve texture, which is safe to read in the
33 // next render pass that'll resolve to `target_`.
34 //
35 // Note that this can only be done when MSAA is being used.
36 return color0.resolve_texture;
37 }
38
39 if (!secondary_color_texture_) {
40 // The second texture is allocated lazily to avoid unused allocations.
41 TextureDescriptor new_descriptor =
42 color0.resolve_texture->GetTextureDescriptor();
43 secondary_color_texture_ = allocator.CreateTexture(new_descriptor);
44
45 if (!secondary_color_texture_) {
46 return nullptr;
47 }
48 }
49
50 // If the color0 resolve texture is the same as the texture, then we're
51 // running on the GLES backend with implicit resolve.
52 if (supports_implicit_msaa_) {
53 auto new_secondary = color0.resolve_texture;
54 color0.resolve_texture = secondary_color_texture_;
55 color0.texture = secondary_color_texture_;
56 secondary_color_texture_ = new_secondary;
57 } else {
58 std::swap(color0.resolve_texture, secondary_color_texture_);
59 }
60
61 target_.SetColorAttachment(color0, 0);
62
63 // Return the previous backdrop texture, which is safe to read in the next
64 // render pass that attaches `target_`.
65 return secondary_color_texture_;
66 }

References impeller::Allocator::CreateTexture(), impeller::RenderTarget::GetColorAttachments(), impeller::RenderTarget::SetColorAttachment(), and VALIDATION_LOG.

Referenced by impeller::InlinePassContext::GetRenderPass().

## ◆ GetRenderTarget()

const RenderTarget & impeller::EntityPassTarget::GetRenderTarget | ( |  | ) | const

Definition at line 68 of file entity_pass_target.cc.

68 {
69 return target_;
70 }

Referenced by impeller::InlinePassContext::GetRenderPass(), and impeller::InlinePassContext::GetTexture().

## ◆ IsValid()

bool impeller::EntityPassTarget::IsValid | ( |  | ) | const

Definition at line 72 of file entity_pass_target.cc.

72 {
73 return target_.IsValid();
74 }

References impeller::RenderTarget::IsValid().

Referenced by impeller::InlinePassContext::IsValid().

The documentation for this class was generated from the following files:

- impeller/entity/entity_pass_target.h
- impeller/entity/entity_pass_target.cc

impeller::RenderTarget::SetColorAttachment
RenderTarget & SetColorAttachment(const ColorAttachment &attachment, size_t index)
Definition: render_target.cc:180
impeller::RenderTarget::GetColorAttachments
const std::map< size_t, ColorAttachment > & GetColorAttachments() const
Definition: render_target.cc:209
impeller::RenderTarget::IsValid
bool IsValid() const
Definition: render_target.cc:34
VALIDATION_LOG
#define VALIDATION_LOG
Definition: validation.h:67