Flutter Impeller
display.cc
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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 
6 
7 #include <vector>
8 
9 #include "flutter/fml/logging.h"
12 
13 namespace impeller {
14 namespace egl {
15 
17  EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
18 
19  if (::eglInitialize(display, nullptr, nullptr) != EGL_TRUE) {
21  return;
22  }
23  display_ = display;
24 }
25 
27  if (display_ != EGL_NO_DISPLAY) {
28  if (::eglTerminate(display_) != EGL_TRUE) {
30  }
31  }
32 }
33 
34 bool Display::IsValid() const {
35  return display_ != EGL_NO_DISPLAY;
36 }
37 
38 std::unique_ptr<Context> Display::CreateContext(const Config& config,
39  const Context* share_context) {
40  const auto& desc = config.GetDescriptor();
41 
42  std::vector<EGLint> attributes;
43  switch (desc.api) {
44  case API::kOpenGL:
45  break;
46  case API::kOpenGLES2:
47  attributes.push_back(EGL_CONTEXT_CLIENT_VERSION);
48  attributes.push_back(2);
49  break;
50  case API::kOpenGLES3:
51  attributes.push_back(EGL_CONTEXT_CLIENT_VERSION);
52  attributes.push_back(3);
53  break;
54  }
55  // Termination sentinel must be present.
56  attributes.push_back(EGL_NONE);
57 
58  auto context = ::eglCreateContext(
59  display_, // display
60  config.GetHandle(), // config
61  share_context != nullptr ? share_context->GetHandle() : nullptr, // share
62  attributes.data() // attributes
63  );
64 
65  if (context == EGL_NO_CONTEXT) {
67  return nullptr;
68  }
69 
70  return std::unique_ptr<Context>(new Context(display_, context));
71 }
72 
73 std::unique_ptr<Config> Display::ChooseConfig(ConfigDescriptor config) const {
74  if (!display_) {
75  return nullptr;
76  }
77 
78  std::vector<EGLint> attributes;
79 
80  {
81  attributes.push_back(EGL_RENDERABLE_TYPE);
82  switch (config.api) {
83  case API::kOpenGL:
84  attributes.push_back(EGL_OPENGL_BIT);
85  break;
86  case API::kOpenGLES2:
87  attributes.push_back(EGL_OPENGL_ES2_BIT);
88  break;
89  case API::kOpenGLES3:
90  attributes.push_back(EGL_OPENGL_ES3_BIT);
91  break;
92  }
93  }
94 
95  {
96  attributes.push_back(EGL_SURFACE_TYPE);
97  switch (config.surface_type) {
99  attributes.push_back(EGL_WINDOW_BIT);
100  break;
102  attributes.push_back(EGL_PBUFFER_BIT);
103  break;
104  }
105  }
106 
107  {
108  switch (config.color_format) {
110  attributes.push_back(EGL_RED_SIZE);
111  attributes.push_back(8);
112  attributes.push_back(EGL_GREEN_SIZE);
113  attributes.push_back(8);
114  attributes.push_back(EGL_BLUE_SIZE);
115  attributes.push_back(8);
116  attributes.push_back(EGL_ALPHA_SIZE);
117  attributes.push_back(8);
118  break;
120  attributes.push_back(EGL_RED_SIZE);
121  attributes.push_back(5);
122  attributes.push_back(EGL_GREEN_SIZE);
123  attributes.push_back(6);
124  attributes.push_back(EGL_BLUE_SIZE);
125  attributes.push_back(5);
126  break;
127  }
128  }
129 
130  {
131  attributes.push_back(EGL_DEPTH_SIZE);
132  attributes.push_back(static_cast<EGLint>(config.depth_bits));
133  }
134 
135  {
136  attributes.push_back(EGL_STENCIL_SIZE);
137  attributes.push_back(static_cast<EGLint>(config.stencil_bits));
138  }
139 
140  {
141  const auto sample_count = static_cast<EGLint>(config.samples);
142  if (sample_count > 1) {
143  attributes.push_back(EGL_SAMPLE_BUFFERS);
144  attributes.push_back(1);
145  attributes.push_back(EGL_SAMPLES);
146  attributes.push_back(sample_count);
147  }
148  }
149 
150  // termination sentinel must be present.
151  attributes.push_back(EGL_NONE);
152 
153  EGLConfig config_out = nullptr;
154  EGLint config_count_out = 0;
155  if (::eglChooseConfig(display_, // display
156  attributes.data(), // attributes (null terminated)
157  &config_out, // matched configs
158  1, // configs array size
159  &config_count_out // match configs count
160  ) != EGL_TRUE) {
162  return nullptr;
163  }
164 
165  if (config_count_out < 1) {
166  return nullptr;
167  }
168 
169  return std::make_unique<Config>(config, config_out);
170 }
171 
172 std::unique_ptr<Surface> Display::CreateWindowSurface(
173  const Config& config,
174  EGLNativeWindowType window) {
175  const EGLint attribs[] = {EGL_NONE};
176  auto surface = ::eglCreateWindowSurface(display_, // display
177  config.GetHandle(), // config
178  window, // window
179  attribs // attrib_list
180  );
181  if (surface == EGL_NO_SURFACE) {
183  return nullptr;
184  }
185  return std::unique_ptr<Surface>(new Surface(display_, surface));
186 }
187 
188 std::unique_ptr<Surface> Display::CreatePixelBufferSurface(const Config& config,
189  size_t width,
190  size_t height) {
191  // clang-format off
192  const EGLint attribs[] = {
193  EGL_WIDTH, static_cast<EGLint>(width),
194  EGL_HEIGHT, static_cast<EGLint>(height),
195  EGL_NONE
196  };
197  // clang-format on
198  auto surface = ::eglCreatePbufferSurface(display_, // display
199  config.GetHandle(), // config
200  attribs // attrib_list
201  );
202  if (surface == EGL_NO_SURFACE) {
204  return nullptr;
205  }
206  return std::unique_ptr<Surface>(new Surface(display_, surface));
207 }
208 
209 const EGLDisplay& Display::GetHandle() const {
210  return display_;
211 }
212 
213 } // namespace egl
214 } // namespace impeller
An EGL config. These are returned by the display to indicate support for a specific config descriptor...
Definition: config.h:64
const EGLConfig & GetHandle() const
Definition: config.cc:21
const ConfigDescriptor & GetDescriptor() const
Definition: config.cc:17
An instance of an EGL context.
Definition: context.h:30
const EGLContext & GetHandle() const
Get the underlying handle to the EGL context.
Definition: context.cc:27
virtual std::unique_ptr< Surface > CreatePixelBufferSurface(const Config &config, size_t width, size_t height)
Create an offscreen pixelbuffer surface. These are of limited use except in the context where applica...
Definition: display.cc:188
virtual std::unique_ptr< Context > CreateContext(const Config &config, const Context *share_context)
Create a context with a supported config. The supported config can be obtained via a successful call ...
Definition: display.cc:38
virtual bool IsValid() const
Definition: display.cc:34
virtual std::unique_ptr< Config > ChooseConfig(ConfigDescriptor config) const
Choose a config that most closely matches a given descriptor. If there are no matches,...
Definition: display.cc:73
const EGLDisplay & GetHandle() const
Definition: display.cc:209
virtual ~Display()
Definition: display.cc:26
virtual std::unique_ptr< Surface > CreateWindowSurface(const Config &config, EGLNativeWindowType window)
Create a window surface. The window is an opaque pointer whose value value is platform specific....
Definition: display.cc:172
An instance of an EGL surface. There is no ability to create surfaces directly. Instead,...
Definition: surface.h:18
#define IMPELLER_LOG_EGL_ERROR
Definition: egl.h:25