[core] separate Backend from View for headless rendering

6 files changed, 148 insertions, 122 deletions

diff --git a/platform/default/glfw_view.cpp b/platform/default/glfw_view.cpp
index 9c54fc4ebf..044181e8c8 100644
--- a/platform/default/glfw_view.cpp
+++ b/platform/default/glfw_view.cpp
@@ -129,6 +129,10 @@ void GLFWView::initialize(mbgl::Map *map_) {
     map->addAnnotationIcon("default_marker", makeSpriteImage(22, 22, 1));
 }
 
+void GLFWView::bind() {
+    MBGL_CHECK_ERROR(glBindFramebuffer(GL_FRAMEBUFFER, 0));
+}
+
 void GLFWView::onKey(GLFWwindow *window, int key, int /*scancode*/, int action, int mods) {
     GLFWView *view = reinterpret_cast<GLFWView *>(glfwGetWindowUserPointer(window));
 
diff --git a/platform/default/headless_backend.cpp b/platform/default/headless_backend.cpp
new file mode 100644
index 0000000000..279a7973c9
--- /dev/null
+++ b/platform/default/headless_backend.cpp
@@ -0,0 +1,56 @@
+#include <mbgl/platform/default/headless_backend.hpp>
+#include <mbgl/platform/default/headless_display.hpp>
+
+#include <cassert>
+#include <stdexcept>
+
+namespace mbgl {
+
+HeadlessBackend::HeadlessBackend() : display(std::make_shared<HeadlessDisplay>()) {
+    activate();
+}
+
+HeadlessBackend::HeadlessBackend(std::shared_ptr<HeadlessDisplay> display_)
+    : display(std::move(display_)) {
+    activate();
+}
+
+HeadlessBackend::~HeadlessBackend() {
+    deactivate();
+    destroyContext();
+}
+
+void HeadlessBackend::activate() {
+    active = true;
+
+    if (!glContext) {
+        if (!display) {
+            throw std::runtime_error("Display is not set");
+        }
+        createContext();
+    }
+
+    activateContext();
+
+    if (!extensionsLoaded) {
+        gl::InitializeExtensions(initializeExtension);
+        extensionsLoaded = true;
+    }
+}
+
+void HeadlessBackend::deactivate() {
+    deactivateContext();
+    active = false;
+}
+
+void HeadlessBackend::invalidate() {
+    assert(false);
+}
+
+void HeadlessBackend::notifyMapChange(MapChange change) {
+    if (mapChangeCallback) {
+        mapChangeCallback(change);
+    }
+}
+
+} // namespace mbgl
diff --git a/platform/default/headless_backend_glx.cpp b/platform/default/headless_backend_glx.cpp
new file mode 100644
index 0000000000..bbfd19345b
--- /dev/null
+++ b/platform/default/headless_backend_glx.cpp
@@ -0,0 +1,67 @@
+#include <mbgl/platform/default/headless_backend.hpp>
+#include <mbgl/platform/default/headless_display.hpp>
+
+#include <mbgl/platform/log.hpp>
+
+// #include <cassert>
+
+#include <GL/glx.h>
+
+namespace mbgl {
+
+gl::glProc HeadlessBackend::initializeExtension(const char* name) {
+    return glXGetProcAddress(reinterpret_cast<const GLubyte*>(name));
+}
+
+void HeadlessBackend::createContext() {
+    xDisplay = display->xDisplay;
+    fbConfigs = display->fbConfigs;
+
+    if (!glContext) {
+        // Try to create a legacy context
+        glContext = glXCreateNewContext(xDisplay, fbConfigs[0], GLX_RGBA_TYPE, None, True);
+        if (glContext) {
+            if (!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 = glXCreatePbuffer(xDisplay, fbConfigs[0], pbufferAttributes);
+}
+
+void HeadlessBackend::destroyContext() {
+    if (glxPbuffer) {
+        glXDestroyPbuffer(xDisplay, glxPbuffer);
+        glxPbuffer = 0;
+    }
+
+    glXDestroyContext(xDisplay, glContext);
+}
+
+void HeadlessBackend::activateContext() {
+    if (!glXMakeContextCurrent(xDisplay, glxPbuffer, glxPbuffer, glContext)) {
+        throw std::runtime_error("Switching OpenGL context failed.\n");
+    }
+}
+
+void HeadlessBackend::deactivateContext() {
+    if (!glXMakeContextCurrent(xDisplay, 0, 0, nullptr)) {
+        throw std::runtime_error("Removing OpenGL context failed.\n");
+    }
+}
+
+} // namespace mbgl
diff --git a/platform/default/headless_display.cpp b/platform/default/headless_display.cpp
index 8b9f3fe04b..b98aef7903 100644
--- a/platform/default/headless_display.cpp
+++ b/platform/default/headless_display.cpp
@@ -1,12 +1,13 @@
 #include <mbgl/platform/default/headless_display.hpp>
 
-#include <cstring>
-#include <stdexcept>
-
 #if MBGL_USE_GLX
 #include <GL/glx.h>
 #endif
 
+#include <cstring>
+#include <stdexcept>
+#include <string>
+
 namespace mbgl {
 
 HeadlessDisplay::HeadlessDisplay() {
diff --git a/platform/default/headless_view.cpp b/platform/default/headless_view.cpp
index 95b196b746..f96b0a7f6d 100644
--- a/platform/default/headless_view.cpp
+++ b/platform/default/headless_view.cpp
@@ -1,34 +1,27 @@
 #include <mbgl/platform/default/headless_view.hpp>
-#include <mbgl/platform/default/headless_display.hpp>
 
-#include <cassert>
+#include <mbgl/gl/gl.hpp>
+
 #include <cstring>
 
 namespace mbgl {
 
 HeadlessView::HeadlessView(float pixelRatio_, uint16_t width, uint16_t height)
-    : display(std::make_shared<HeadlessDisplay>())
-    , pixelRatio(pixelRatio_)
-    , dimensions({{ width, height }})
-    , needsResize(true) {
-}
-
-HeadlessView::HeadlessView(std::shared_ptr<HeadlessDisplay> display_,
-                           float pixelRatio_,
-                           uint16_t width,
-                           uint16_t height)
-    : display(std::move(display_))
-    , pixelRatio(pixelRatio_)
-    , dimensions({{ width, height }})
-    , needsResize(true) {
+    : pixelRatio(pixelRatio_), dimensions({ { width, height } }), needsResize(true) {
 }
 
 HeadlessView::~HeadlessView() {
-    activate();
     clearBuffers();
-    deactivate();
+}
 
-    destroyContext();
+void HeadlessView::bind() {
+    if (needsResize) {
+        clearBuffers();
+        resizeFramebuffer();
+        needsResize = false;
+    } else {
+        bindFramebuffer();
+    }
 }
 
 void HeadlessView::resize(const uint16_t width, const uint16_t height) {
@@ -41,8 +34,6 @@ void HeadlessView::resize(const uint16_t width, const uint16_t height) {
 }
 
 PremultipliedImage HeadlessView::readStillImage(std::array<uint16_t, 2> size) {
-    assert(active);
-
     if (!size[0] || !size[1]) {
         size[0] = dimensions[0] * pixelRatio;
         size[1] = dimensions[1] * pixelRatio;
@@ -76,43 +67,4 @@ std::array<uint16_t, 2> HeadlessView::getFramebufferSize() const {
               static_cast<uint16_t>(dimensions[1] * pixelRatio) }};
 }
 
-void HeadlessView::activate() {
-    active = true;
-
-    if (!glContext) {
-        if (!display) {
-            throw std::runtime_error("Display is not set");
-        }
-        createContext();
-    }
-
-    activateContext();
-
-    if (!extensionsLoaded) {
-        gl::InitializeExtensions(initializeExtension);
-        extensionsLoaded = true;
-    }
-
-    if (needsResize) {
-        clearBuffers();
-        resizeFramebuffer();
-        needsResize = false;
-    }
-}
-
-void HeadlessView::deactivate() {
-    deactivateContext();
-    active = false;
-}
-
-void HeadlessView::invalidate() {
-    assert(false);
-}
-
-void HeadlessView::notifyMapChange(MapChange change) {
-    if (mapChangeCallback) {
-        mapChangeCallback(change);
-    }
-}
-
 } // namespace mbgl
diff --git a/platform/default/headless_view_glx.cpp b/platform/default/headless_view_glx.cpp
index 55d9313f99..08f0da8751 100644
--- a/platform/default/headless_view_glx.cpp
+++ b/platform/default/headless_view_glx.cpp
@@ -1,54 +1,14 @@
 #include <mbgl/platform/default/headless_view.hpp>
-#include <mbgl/platform/default/headless_display.hpp>
-#include <mbgl/platform/log.hpp>
 
-#include <cassert>
+#include <mbgl/gl/gl.hpp>
 
-#include <GL/glx.h>
+#include <cassert>
 
 namespace mbgl {
 
-gl::glProc HeadlessView::initializeExtension(const char* name) {
-    return glXGetProcAddress(reinterpret_cast<const GLubyte*>(name));
-}
-
-void HeadlessView::createContext() {
-    xDisplay = display->xDisplay;
-    fbConfigs = display->fbConfigs;
-
-    if (!glContext) {
-        // Try to create a legacy context
-        glContext = glXCreateNewContext(xDisplay, fbConfigs[0], GLX_RGBA_TYPE, None, True);
-        if (glContext) {
-            if (!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 = glXCreatePbuffer(xDisplay, fbConfigs[0], pbufferAttributes);
-}
-
-void HeadlessView::destroyContext() {
-    if (glxPbuffer) {
-        glXDestroyPbuffer(xDisplay, glxPbuffer);
-        glxPbuffer = 0;
-    }
-
-    glXDestroyContext(xDisplay, glContext);
+void HeadlessView::bindFramebuffer() {
+    assert(fbo);
+    MBGL_CHECK_ERROR(glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo));
 }
 
 void HeadlessView::resizeFramebuffer() {
@@ -93,8 +53,6 @@ void HeadlessView::resizeFramebuffer() {
 }
 
 void HeadlessView::clearBuffers() {
-    assert(active);
-
     MBGL_CHECK_ERROR(glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0));
 
     if (fbo) {
@@ -113,16 +71,4 @@ void HeadlessView::clearBuffers() {
     }
 }
 
-void HeadlessView::activateContext() {
-    if (!glXMakeContextCurrent(xDisplay, glxPbuffer, glxPbuffer, glContext)) {
-        throw std::runtime_error("Switching OpenGL context failed.\n");
-    }
-}
-
-void HeadlessView::deactivateContext() {
-    if (!glXMakeContextCurrent(xDisplay, 0, 0, nullptr)) {
-        throw std::runtime_error("Removing OpenGL context failed.\n");
-    }
-}
-
 } // namespace mbgl