/* * Copyright 2011-2022 Branimir Karadzic. All rights reserved. * License: https://github.com/bkaradzic/bgfx/blob/master/LICENSE */ #include "bgfx_p.h" #if BGFX_CONFIG_RENDERER_OPENGLES # include "renderer_gl.h" # if BGFX_USE_HTML5 # include "emscripten.h" // from emscripten gl.c, because we're not going to go // through egl extern "C" void* emscripten_GetProcAddress(const char *name_); extern "C" void* emscripten_webgl1_get_proc_address(const char *name_); extern "C" void* emscripten_webgl2_get_proc_address(const char *name_); namespace bgfx { namespace gl { # define GL_IMPORT(_optional, _proto, _func, _import) _proto _func = NULL # include "glimports.h" static EmscriptenWebGLContextAttributes s_attrs; struct SwapChainGL { SwapChainGL(int _context, const char* _canvas) : m_context(_context) { m_canvas = (char*)BX_ALLOC(g_allocator, strlen(_canvas) + 1); strcpy(m_canvas, _canvas); makeCurrent(); GL_CHECK(glClearColor(0.0f, 0.0f, 0.0f, 0.0f) ); GL_CHECK(glClear(GL_COLOR_BUFFER_BIT) ); swapBuffers(); GL_CHECK(glClear(GL_COLOR_BUFFER_BIT) ); swapBuffers(); } ~SwapChainGL() { EMSCRIPTEN_CHECK(emscripten_webgl_destroy_context(m_context) ); BX_FREE(g_allocator, m_canvas); } void makeCurrent() { EMSCRIPTEN_CHECK(emscripten_webgl_make_context_current(m_context) ); } void swapBuffers() { // There is no swapBuffers equivalent. A swap happens whenever control is returned back // to the browser. } int m_context; char* m_canvas; }; void GlContext::create(uint32_t _width, uint32_t _height, uint32_t /*_flags*/) { // assert? if (m_primary != NULL) return; const char* canvas = (const char*) g_platformData.nwh; EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = (EMSCRIPTEN_WEBGL_CONTEXT_HANDLE) g_platformData.context; if (context > 0) { if (emscripten_webgl_get_context_attributes(context, &s_attrs) >= 0) { import(s_attrs.majorVersion); m_primary = BX_NEW(g_allocator, SwapChainGL)(context, canvas); } else { BX_TRACE("Invalid WebGL context. (Canvas handle: '%s', context handle: %d)", canvas, context); } } else { m_primary = createSwapChain((void*)canvas, (int)_width, (int)_height); } if (0 != _width && 0 != _height) { EMSCRIPTEN_CHECK(emscripten_set_canvas_element_size(canvas, (int)_width, (int)_height) ); } makeCurrent(m_primary); } void GlContext::destroy() { if (m_primary) { if (m_current == m_primary) { m_current = NULL; } BX_DELETE(g_allocator, m_primary); m_primary = NULL; } } void GlContext::resize(uint32_t _width, uint32_t _height, uint32_t /* _flags */) { if (m_primary == NULL) { return; } EMSCRIPTEN_CHECK(emscripten_set_canvas_element_size(m_primary->m_canvas, (int) _width, (int) _height) ); } SwapChainGL* GlContext::createSwapChain(void* _nwh, int _width, int _height) { emscripten_webgl_init_context_attributes(&s_attrs); BX_UNUSED(_width, _height); // Work around bug https://bugs.chromium.org/p/chromium/issues/detail?id=1045643 in Chrome // by having alpha always enabled. s_attrs.alpha = true; s_attrs.premultipliedAlpha = false; s_attrs.depth = true; s_attrs.stencil = true; s_attrs.enableExtensionsByDefault = true; s_attrs.antialias = false; s_attrs.minorVersion = 0; const char* canvas = (const char*) _nwh; int32_t error = 0; for (int version = 2; version >= 1; --version) { s_attrs.majorVersion = version; EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context(canvas, &s_attrs); if (context > 0) { EMSCRIPTEN_CHECK(emscripten_webgl_make_context_current(context) ); SwapChainGL* swapChain = BX_NEW(g_allocator, SwapChainGL)(context, canvas); import(version); return swapChain; } error = (int32_t)context; } BX_TRACE("Failed to create WebGL context. (Canvas handle: '%s', last attempt error %d)", canvas, error); BX_UNUSED(error); return NULL; } uint64_t GlContext::getCaps() const { return BGFX_CAPS_SWAP_CHAIN; } void GlContext::destroySwapChain(SwapChainGL* _swapChain) { BX_DELETE(g_allocator, _swapChain); } void GlContext::swap(SwapChainGL* /* _swapChain */) { } void GlContext::makeCurrent(SwapChainGL* _swapChain) { if (m_current != _swapChain) { m_current = _swapChain; if (NULL == _swapChain) { if (NULL != m_primary) { m_primary->makeCurrent(); } } else { _swapChain->makeCurrent(); } } } template static Fn getProcAddress(int _version, const char* _name) { Fn func = reinterpret_cast(emscripten_webgl1_get_proc_address(_name) ); if (NULL == func && _version >= 2) { func = reinterpret_cast(emscripten_webgl2_get_proc_address(_name) ); } return func; } void GlContext::import(int _webGLVersion) { BX_TRACE("Import:"); # define GL_EXTENSION(_optional, _proto, _func, _import) \ { \ if (NULL == _func) \ { \ _func = getProcAddress<_proto>(_webGLVersion, #_import); \ BX_TRACE("\t%p " #_func " (" #_import ")", _func); \ BGFX_FATAL(_optional || NULL != _func, Fatal::UnableToInitialize \ , "Failed to create WebGL/OpenGLES context. GetProcAddress(\"%s\")" \ , #_import \ ); \ } \ } # include "glimports.h" # undef GL_EXTENSION } } /* namespace gl */ } // namespace bgfx # endif // BGFX_USE_EGL #endif // (BGFX_CONFIG_RENDERER_OPENGLES || BGFX_CONFIG_RENDERER_OPENGL)