6fcac0f580
We need a surface to activate a context. Some implementation don't seem to error when passing EGL_NO_SURFACE, but it doesn't seem standards compliant.
102 lines
3.2 KiB
C++
102 lines
3.2 KiB
C++
#include <mbgl/gl/headless_backend.hpp>
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#include <mbgl/gl/headless_display.hpp>
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#include <mbgl/util/logging.hpp>
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#include <EGL/egl.h>
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#include <cassert>
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namespace mbgl {
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struct EGLImpl : public HeadlessBackend::Impl {
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EGLImpl(EGLContext glContext_, EGLDisplay display_, EGLConfig config_)
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: glContext(glContext_),
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display(display_),
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config(config_) {
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// Create a dummy pbuffer. We will render to framebuffers anyway, but we need a pbuffer to
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// activate the context.
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// Note that to be able to create pbuffer surfaces, we need to choose a config that
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// includes EGL_SURFACE_TYPE, EGL_PBUFFER_BIT in HeadlessDisplay.
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const EGLint surfAttribs[] = {
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EGL_WIDTH, 8,
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EGL_HEIGHT, 8,
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EGL_LARGEST_PBUFFER, EGL_TRUE,
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EGL_NONE
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};
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glSurface = eglCreatePbufferSurface(display, config, surfAttribs);
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if (glSurface == EGL_NO_SURFACE) {
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throw std::runtime_error("Could not create surface: " + std::to_string(eglGetError()));
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}
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}
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~EGLImpl() {
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if (glSurface != EGL_NO_SURFACE) {
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if (!eglDestroySurface(display, glSurface)) {
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throw std::runtime_error("Failed to destroy EGL surface.\n");
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}
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glSurface = EGL_NO_SURFACE;
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}
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if (!eglDestroyContext(display, glContext)) {
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throw std::runtime_error("Failed to destroy EGL context.\n");
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}
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}
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void activateContext() final {
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if (!eglMakeCurrent(display, glSurface, glSurface, glContext)) {
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throw std::runtime_error("Switching OpenGL context failed.\n");
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}
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}
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void deactivateContext() final {
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if (!eglMakeCurrent(display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT)) {
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throw std::runtime_error("Removing OpenGL context failed.\n");
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}
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}
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EGLContext glContext = EGL_NO_CONTEXT;
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EGLDisplay display = EGL_NO_DISPLAY;
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EGLConfig config = 0;
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EGLSurface glSurface = EGL_NO_SURFACE;
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};
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gl::ProcAddress HeadlessBackend::initializeExtension(const char* name) {
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return eglGetProcAddress(name);
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}
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bool HeadlessBackend::hasDisplay() {
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if (!display) {
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display.reset(new HeadlessDisplay);
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}
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return bool(display);
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};
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void HeadlessBackend::createContext() {
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assert(!hasContext());
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assert(hasDisplay());
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EGLDisplay display_ = display->attribute<EGLDisplay>();
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EGLConfig& config = display->attribute<EGLConfig&>();
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// EGL initializes the context client version to 1 by default. We want to
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// use OpenGL ES 2.0 which has the ability to create shader and program
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// objects and also to write vertex and fragment shaders in the OpenGL ES
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// Shading Language.
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const EGLint attribs[] = {
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EGL_CONTEXT_CLIENT_VERSION, 2,
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EGL_NONE
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};
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EGLContext glContext = eglCreateContext(display_, config, EGL_NO_CONTEXT, attribs);
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if (glContext == EGL_NO_CONTEXT) {
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mbgl::Log::Error(mbgl::Event::OpenGL, "eglCreateContext() returned error 0x%04x",
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eglGetError());
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throw std::runtime_error("Error creating the EGL context object.\n");
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}
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impl.reset(new EGLImpl(glContext, display_, config));
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}
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} // namespace mbgl
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