1 files changed, 103 insertions, 0 deletions
diff --git a/platform/linux/src/headless_backend_egl.cpp b/platform/linux/src/headless_backend_egl.cpp
new file mode 100644
index 0000000000..87e7c1d0ed
--- /dev/null
+++ b/platform/linux/src/headless_backend_egl.cpp
@@ -0,0 +1,103 @@
+#include <mbgl/gl/headless_backend.hpp>
+#include <mbgl/gl/headless_display.hpp>
+
+#include <mbgl/util/logging.hpp>
+
+#include <EGL/egl.h>
+
+#include <cassert>
+
+namespace mbgl {
+
+struct EGLImpl : public HeadlessBackend::Impl {
+    EGLImpl(EGLContext glContext_, EGLDisplay display_, EGLConfig config_)
+            : glContext(glContext_),
+              display(display_),
+              config(config_) {
+#if __ANDROID__
+        // Create a pixel buffer surface (in conjunction with EGL_SURFACE_TYPE, EGL_PBUFFER_BIT).
+        const EGLint surfAttribs[] = {
+            EGL_WIDTH, 512,
+            EGL_HEIGHT, 512,
+            EGL_LARGEST_PBUFFER, EGL_TRUE,
+            EGL_NONE
+        };
+
+        glSurface = eglCreatePbufferSurface(display, config, surfAttribs);
+        if (glSurface == EGL_NO_SURFACE) {
+            throw std::runtime_error("Could not create surface: " + std::to_string(eglGetError()));
+        }
+#endif // __ANDROID__
+    }
+
+    ~EGLImpl() {
+        if (glContext != eglGetCurrentContext()) {
+            activateContext();
+        }
+        if (!eglDestroyContext(display, glContext)) {
+            throw std::runtime_error("Failed to destroy EGL context.\n");
+        }
+        if (glSurface != EGL_NO_SURFACE) {
+            if (!eglDestroySurface(display, glSurface)) {
+                throw std::runtime_error("Failed to destroy EGL context.\n");
+            }
+            glSurface = EGL_NO_SURFACE;
+        }
+    }
+
+    void activateContext() final {
+        if (!eglMakeCurrent(display, glSurface, glSurface, glContext)) {
+            throw std::runtime_error("Switching OpenGL context failed.\n");
+        }
+    }
+
+    void deactivateContext() final {
+        if (!eglMakeCurrent(display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT)) {
+            throw std::runtime_error("Removing OpenGL context failed.\n");
+        }
+    }
+
+    EGLContext glContext = EGL_NO_CONTEXT;
+    EGLDisplay display = EGL_NO_DISPLAY;
+    EGLConfig config = 0;
+    EGLSurface glSurface = EGL_NO_SURFACE;
+};
+
+gl::glProc HeadlessBackend::initializeExtension(const char* name) {
+    return eglGetProcAddress(name);
+}
+
+bool HeadlessBackend::hasDisplay() {
+    if (!display) {
+        display.reset(new HeadlessDisplay);
+    }
+    return bool(display);
+};
+
+void HeadlessBackend::createContext() {
+    assert(!hasContext());
+    assert(hasDisplay());
+
+    EGLDisplay display_ = display->attribute<EGLDisplay>();
+    EGLConfig& config = display->attribute<EGLConfig&>();
+
+    // EGL initializes the context client version to 1 by default. We want to
+    // use OpenGL ES 2.0 which has the ability to create shader and program
+    // objects and also to write vertex and fragment shaders in the OpenGL ES
+    // Shading Language.
+    const EGLint attribs[] = {
+        EGL_CONTEXT_CLIENT_VERSION, 2,
+        EGL_NONE
+    };
+
+    EGLContext glContext = eglCreateContext(display_, config, EGL_NO_CONTEXT, attribs);
+    if (glContext == EGL_NO_CONTEXT) {
+        mbgl::Log::Error(mbgl::Event::OpenGL, "eglCreateContext() returned error 0x%04x",
+                         eglGetError());
+        throw std::runtime_error("Error creating the EGL context object.\n");
+    }
+
+    impl.reset(new EGLImpl(glContext, display_, config));
+}
+
+} // namespace mbgl