123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204 | // Copyright (C) 2018 The Qt Company Ltd.// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only#include"qwasmopenglcontext.h"#include"qwasmoffscreensurface.h"#include"qwasmintegration.h"#include <EGL/egl.h>#include <emscripten/bind.h>#include <emscripten/val.h>namespace{voidqtDoNothing(emscripten::val) { }}// namespaceEMSCRIPTEN_BINDINGS(qwasmopenglcontext){function("qtDoNothing", &qtDoNothing);} QT_BEGIN_NAMESPACE QWasmOpenGLContext::QWasmOpenGLContext(QOpenGLContext *context):m_actualFormat(context->format()),m_qGlContext(context){ m_actualFormat.setRenderableType(QSurfaceFormat::OpenGLES);// if we set one, we need to set the other as well since in webgl, these are tied togetherif(m_actualFormat.depthBufferSize() <0&& m_actualFormat.stencilBufferSize() >0) m_actualFormat.setDepthBufferSize(16);if(m_actualFormat.stencilBufferSize() <0&& m_actualFormat.depthBufferSize() >0) m_actualFormat.setStencilBufferSize(8);}QWasmOpenGLContext::~QWasmOpenGLContext(){// Destroy GL context. Work around bug in emscripten_webgl_destroy_context// which removes all event handlers on the canvas by temporarily replacing the function// that does the removal with a function that does nothing.destroyWebGLContext(m_ownedWebGLContext.handle);}boolQWasmOpenGLContext::isOpenGLVersionSupported(QSurfaceFormat format){// Version check: support WebGL 1 and 2:// (ES) 2.0 -> WebGL 1.0// (ES) 3.0 -> WebGL 2.0// [we don't expect that new WebGL versions will be created]return((format.majorVersion() ==2&& format.minorVersion() ==0) ||(format.majorVersion() ==3&& format.minorVersion() ==0));} EMSCRIPTEN_WEBGL_CONTEXT_HANDLE QWasmOpenGLContext::obtainEmscriptenContext(QPlatformSurface *surface){if(m_ownedWebGLContext.surface == surface)return m_ownedWebGLContext.handle;if(surface->surface()->surfaceClass() ==QSurface::Offscreen) {// Reuse the existing context for offscreen drawing, even if it happens to be a canvas// context. This is because it is impossible to re-home an existing context to the// new surface and works as an emulation measure.if(m_ownedWebGLContext.handle)return m_ownedWebGLContext.handle;// The non-shared offscreen context is heavily limited on WASM, but we provide it// anyway for potential pixel readbacks. m_ownedWebGLContext = QOpenGLContextData{ .surface = surface,.handle =createEmscriptenContext(static_cast<QWasmOffscreenSurface *>(surface)->id(), m_actualFormat) };}else{destroyWebGLContext(m_ownedWebGLContext.handle);// Create a full on-screen context for the window canvas. m_ownedWebGLContext = QOpenGLContextData{.surface = surface,.handle =createEmscriptenContext(static_cast<QWasmWindow *>(surface)->canvasSelector(), m_actualFormat)};} EmscriptenWebGLContextAttributes actualAttributes; EMSCRIPTEN_RESULT attributesResult =emscripten_webgl_get_context_attributes(m_ownedWebGLContext.handle, &actualAttributes);if(attributesResult == EMSCRIPTEN_RESULT_SUCCESS) {if(actualAttributes.majorVersion ==1) { m_actualFormat.setMajorVersion(2);}else if(actualAttributes.majorVersion ==2) { m_actualFormat.setMajorVersion(3);} m_actualFormat.setMinorVersion(0);}return m_ownedWebGLContext.handle;}voidQWasmOpenGLContext::destroyWebGLContext(EMSCRIPTEN_WEBGL_CONTEXT_HANDLE contextHandle){if(!contextHandle)return;emscripten::val jsEvents =emscripten::val::module_property("JSEvents");emscripten::val savedRemoveAllHandlersOnTargetFunction = jsEvents["removeAllHandlersOnTarget"]; jsEvents.set("removeAllHandlersOnTarget",emscripten::val::module_property("qtDoNothing"));emscripten_webgl_destroy_context(contextHandle); jsEvents.set("removeAllHandlersOnTarget", savedRemoveAllHandlersOnTargetFunction);} EMSCRIPTEN_WEBGL_CONTEXT_HANDLE QWasmOpenGLContext::createEmscriptenContext(conststd::string &canvasSelector, QSurfaceFormat format){ EmscriptenWebGLContextAttributes attributes;emscripten_webgl_init_context_attributes(&attributes);// Populate with default attributes attributes.powerPreference = EM_WEBGL_POWER_PREFERENCE_HIGH_PERFORMANCE; attributes.failIfMajorPerformanceCaveat =false; attributes.antialias =true; attributes.enableExtensionsByDefault =true; attributes.majorVersion =2;// try highest supported version ES3.0 / WebGL 2.0 attributes.minorVersion =0;// emscripten only supports minor version 0// WebGL doesn't allow separate attach buffers to STENCIL_ATTACHMENT and DEPTH_ATTACHMENT// we need both or noneconst bool useDepthStencil = (format.depthBufferSize() >0|| format.stencilBufferSize() >0);// WebGL offers enable/disable control but not size control for these attributes.alpha = format.alphaBufferSize() >0; attributes.depth = useDepthStencil; attributes.stencil = useDepthStencil; EMSCRIPTEN_RESULT contextResult =emscripten_webgl_create_context(canvasSelector.c_str(), &attributes);if(contextResult <=0) {// fallback to opengles2/webgl1// for devices that do not support opengles3/webgl2 attributes.majorVersion =1; contextResult =emscripten_webgl_create_context(canvasSelector.c_str(), &attributes);}return contextResult;} QSurfaceFormat QWasmOpenGLContext::format()const{return m_actualFormat;} GLuint QWasmOpenGLContext::defaultFramebufferObject(QPlatformSurface *surface)const{returnQPlatformOpenGLContext::defaultFramebufferObject(surface);}boolQWasmOpenGLContext::makeCurrent(QPlatformSurface *surface){static bool sentSharingWarning =false;if(!sentSharingWarning &&isSharing()) {qWarning() <<"The functionality for sharing OpenGL contexts is limited, see documentation"; sentSharingWarning =true;}if(auto*shareContext = m_qGlContext->shareContext())return shareContext->makeCurrent(surface->surface());constauto context =obtainEmscriptenContext(surface);if(!context)return false; m_usedWebGLContextHandle = context;returnemscripten_webgl_make_context_current(context) == EMSCRIPTEN_RESULT_SUCCESS;}voidQWasmOpenGLContext::swapBuffers(QPlatformSurface *surface){Q_UNUSED(surface);// No swapbuffers on WebGl}voidQWasmOpenGLContext::doneCurrent(){// No doneCurrent on WebGl}boolQWasmOpenGLContext::isSharing()const{return m_qGlContext->shareContext();}boolQWasmOpenGLContext::isValid()const{if(!isOpenGLVersionSupported(m_actualFormat))return false;// Note: we get isValid() calls before we see the surface and can// create a native context, so no context is also a valid state.return!m_usedWebGLContextHandle || !emscripten_is_webgl_context_lost(m_usedWebGLContextHandle);} QFunctionPointer QWasmOpenGLContext::getProcAddress(const char*procName){return reinterpret_cast<QFunctionPointer>(eglGetProcAddress(procName));} QT_END_NAMESPACE
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