1 files changed, 87 insertions, 0 deletions
diff --git a/platform/linux/src/headless_backend_glx.cpp b/platform/linux/src/headless_backend_glx.cpp
new file mode 100644
index 0000000000..5791f1892f
--- /dev/null
+++ b/platform/linux/src/headless_backend_glx.cpp
@@ -0,0 +1,87 @@
+#include <mbgl/gl/headless_backend.hpp>
+#include <mbgl/gl/headless_display.hpp>
+
+#include <mbgl/util/logging.hpp>
+
+#include <cassert>
+
+#include <GL/glx.h>
+
+namespace mbgl {
+
+struct GLXImpl : public HeadlessBackend::Impl {
+    GLXImpl(GLXContext glContext_, GLXPbuffer glxPbuffer_, Display* xDisplay_, GLXFBConfig* fbConfigs_)
+            : glContext(glContext_),
+              glxPbuffer(glxPbuffer_),
+              xDisplay(xDisplay_),
+              fbConfigs(fbConfigs_) {
+    }
+
+    ~GLXImpl() {
+        if (glxPbuffer) {
+            glXDestroyPbuffer(xDisplay, glxPbuffer);
+        }
+        glXDestroyContext(xDisplay, glContext);
+    }
+
+    void activateContext() final {
+        if (!glXMakeContextCurrent(xDisplay, glxPbuffer, glxPbuffer, glContext)) {
+            throw std::runtime_error("Switching OpenGL context failed.\n");
+        }
+    }
+
+    void deactivateContext() final {
+        if (!glXMakeContextCurrent(xDisplay, 0, 0, nullptr)) {
+            throw std::runtime_error("Removing OpenGL context failed.\n");
+        }
+    }
+
+    GLXContext glContext = nullptr;
+    GLXPbuffer glxPbuffer = 0;
+
+    // Needed for ImplDeleter.
+    Display* xDisplay = nullptr;
+    GLXFBConfig* fbConfigs = nullptr;
+};
+
+gl::glProc HeadlessBackend::initializeExtension(const char* name) {
+    return glXGetProcAddress(reinterpret_cast<const GLubyte*>(name));
+}
+
+bool HeadlessBackend::hasDisplay() {
+    if (!display) {
+        display.reset(new HeadlessDisplay);
+    }
+    return bool(display);
+};
+
+void HeadlessBackend::createContext() {
+    assert(!hasContext());
+
+    Display* xDisplay = display->attribute<Display*>();
+    GLXFBConfig* fbConfigs = display->attribute<GLXFBConfig*>();
+
+    // Try to create a legacy context.
+    GLXContext glContext = glXCreateNewContext(xDisplay, fbConfigs[0], GLX_RGBA_TYPE, None, True);
+    if (glContext && !glXIsDirect(xDisplay, glContext)) {
+        Log::Error(Event::OpenGL, "failed to create direct OpenGL Legacy context");
+        glXDestroyContext(xDisplay, glContext);
+        glContext = nullptr;
+    }
+    if (glContext == nullptr) {
+        throw std::runtime_error("Error creating GL context object.");
+    }
+
+    // Create a dummy pbuffer. We will render to framebuffers anyway, but we need a pbuffer to
+    // activate the context.
+    int pbufferAttributes[] = {
+        GLX_PBUFFER_WIDTH, 8,
+        GLX_PBUFFER_HEIGHT, 8,
+        None
+    };
+    GLXPbuffer glxPbuffer = glXCreatePbuffer(xDisplay, fbConfigs[0], pbufferAttributes);
+
+    impl.reset(new GLXImpl(glContext, glxPbuffer, xDisplay, fbConfigs));
+}
+
+} // namespace mbgl