Work around issue with Unicode shaders with threaded Emscripten.

doc/changelog.dox

@@ -76,6 +76,10 @@ See also:
 
 -   Engine startup info was not properly printed to Android log since
     introducing the `--magnum-log` option in version 2018.02
+-   Working around Emscripten issue where `-s USE_PTHREADS=1` would cause all
+    shader sources containing Unicode characters to be truncated to empty
+    strings. See the @cpp "emscripten-pthreads-broken-unicode-shader-sources" @ce
+    workaround description for details.
 
 @subsection changelog-latest-deprecated Deprecated APIs
 

src/Magnum/CMakeLists.txt

@@ -59,6 +59,7 @@ set(Magnum_SRCS
     Implementation/MeshState.cpp
     Implementation/RendererState.cpp
     Implementation/ShaderProgramState.cpp
+    Implementation/ShaderState.cpp
     Implementation/State.cpp
     Implementation/TextureState.cpp
     Implementation/driverSpecific.cpp

src/Magnum/Implementation/ShaderState.cpp

@@ -0,0 +1,64 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018
+              Vladimír Vondruš <mosra@centrum.cz>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+#include "ShaderState.h"
+
+#include "Magnum/Shader.h"
+
+#if defined(CORRADE_TARGET_EMSCRIPTEN) && defined(__EMSCRIPTEN_PTHREADS__)
+#include "Magnum/Context.h"
+#endif
+
+namespace Magnum { namespace Implementation {
+
+ShaderState::ShaderState(Context& context, std::vector<std::string>&):
+    maxVertexOutputComponents{}, maxFragmentInputComponents{},
+    #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+    maxTessellationControlInputComponents{}, maxTessellationControlOutputComponents{}, maxTessellationControlTotalOutputComponents{}, maxTessellationEvaluationInputComponents{}, maxTessellationEvaluationOutputComponents{}, maxGeometryInputComponents{}, maxGeometryOutputComponents{}, maxGeometryTotalOutputComponents{}, maxAtomicCounterBuffers{}, maxCombinedAtomicCounterBuffers{}, maxAtomicCounters{}, maxCombinedAtomicCounters{}, maxImageUniforms{}, maxCombinedImageUniforms{}, maxShaderStorageBlocks{}, maxCombinedShaderStorageBlocks{},
+    #endif
+    maxTextureImageUnits{}, maxTextureImageUnitsCombined{},
+    #ifndef MAGNUM_TARGET_GLES2
+    maxUniformBlocks{}, maxCombinedUniformBlocks{},
+    #endif
+    maxUniformComponents{}, maxUniformComponentsCombined{}
+    #ifndef MAGNUM_TARGET_GLES2
+    , maxCombinedUniformComponents{}
+    #endif
+{
+    #if defined(CORRADE_TARGET_EMSCRIPTEN) && defined(__EMSCRIPTEN_PTHREADS__)
+    if(!context.isDriverWorkaroundDisabled("emscripten-pthreads-broken-unicode-shader-sources")) {
+        addSourceImplementation = &Shader::addSourceImplementationEmscriptenPthread;
+    } else
+    #endif
+    {
+        addSourceImplementation = &Shader::addSourceImplementationDefault;
+    }
+
+    #if !defined(CORRADE_TARGET_EMSCRIPTEN) || !defined(__EMSCRIPTEN_PTHREADS__)
+    static_cast<void>(context);
+    #endif
+}
+
+}}

src/Magnum/Implementation/ShaderState.h

@@ -25,27 +25,23 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#include <string>
+#include <vector>
+
+#include "Magnum/Magnum.h"
 #include "Magnum/OpenGL.h"
-#include "Magnum/Types.h"
-#include "Magnum/configure.h"
+
+#ifdef _MSC_VER
+/* Otherwise the member function pointers will have different size based on
+   whether the header was included or not. CAUSES SERIOUS MEMORY CORRUPTION AND
+   IS NOT CAUGHT BY ANY WARNING WHATSOEVER! AARGH! */
+#include "Magnum/Shader.h"
+#endif
 
 namespace Magnum { namespace Implementation {
 
 struct ShaderState {
-    explicit ShaderState():
-        maxVertexOutputComponents{}, maxFragmentInputComponents{},
-        #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
-        maxTessellationControlInputComponents{}, maxTessellationControlOutputComponents{}, maxTessellationControlTotalOutputComponents{}, maxTessellationEvaluationInputComponents{}, maxTessellationEvaluationOutputComponents{}, maxGeometryInputComponents{}, maxGeometryOutputComponents{}, maxGeometryTotalOutputComponents{}, maxAtomicCounterBuffers{}, maxCombinedAtomicCounterBuffers{}, maxAtomicCounters{}, maxCombinedAtomicCounters{}, maxImageUniforms{}, maxCombinedImageUniforms{}, maxShaderStorageBlocks{}, maxCombinedShaderStorageBlocks{},
-        #endif
-        maxTextureImageUnits{}, maxTextureImageUnitsCombined{},
-        #ifndef MAGNUM_TARGET_GLES2
-        maxUniformBlocks{}, maxCombinedUniformBlocks{},
-        #endif
-        maxUniformComponents{}, maxUniformComponentsCombined{}
-        #ifndef MAGNUM_TARGET_GLES2
-        , maxCombinedUniformComponents{}
-        #endif
-        {}
+    explicit ShaderState(Context& context, std::vector<std::string>& extensions);
 
     enum: std::size_t {
         #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
@@ -55,6 +51,8 @@ struct ShaderState {
         #endif
     };
 
+    void(Shader::*addSourceImplementation)(std::string);
+
     GLint maxVertexOutputComponents,
         maxFragmentInputComponents;
     #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)

src/Magnum/Implementation/State.cpp

@@ -71,7 +71,7 @@ State::State(Context& context, std::ostream* const out) {
     query.reset(new QueryState{context, extensions});
     #endif
     renderer.reset(new RendererState{context, extensions});
-    shader.reset(new ShaderState);
+    shader.reset(new ShaderState(context, extensions));
     shaderProgram.reset(new ShaderProgramState{context, extensions});
     texture.reset(new TextureState{context, extensions});
     #ifndef MAGNUM_TARGET_GLES2

src/Magnum/Implementation/driverSpecific.cpp

@@ -103,7 +103,15 @@ namespace {
            with copies from host memory, not with buffer images. Seems to be
            fixed in Mesa 13, but I have no such system to verify that on.
            https://github.com/mesa3d/mesa/commit/2aa9ff0cda1f6ad97c83d5583fab7a84efabe19e */
-        "svga3d-texture-upload-slice-by-slice"
+        "svga3d-texture-upload-slice-by-slice",
+
+        #if defined(CORRADE_TARGET_EMSCRIPTEN) && defined(__EMSCRIPTEN_PTHREADS__)
+        /* Shader sources containing UTF-8 characters are converted to empty
+           strings when running on Emscripten with -s USE_PTHREADS=1. Working
+           around that by replacing all chars > 127 with spaces. Relevant code:
+           https://github.com/kripken/emscripten/blob/7f89560101843198787530731f40a65288f6f15f/src/fetch-worker.js#L54-L58 */
+        "emscripten-pthreads-broken-unicode-shader-sources"
+        #endif
     };
 }
 

src/Magnum/Shader.cpp

@@ -704,6 +704,8 @@ std::vector<std::string> Shader::sources() const { return _sources; }
 
 Shader& Shader::addSource(std::string source) {
     if(!source.empty()) {
+        auto addSource = Context::current().state().shader->addSourceImplementation;
+
         /* Fix line numbers, so line 41 of third added file is marked as 3(41)
            in case shader version was not Version::None, because then source 0
            is the #version directive added in constructor.
@@ -715,15 +717,28 @@ Shader& Shader::addSource(std::string source) {
            order to avoid complex logic in compile() where we assert for at
            least some user-provided source, an empty string is added here
            instead. */
-        if(!_sources.empty()) _sources.push_back("#line 1 " + std::to_string((_sources.size()+1)/2) + '\n');
-        else _sources.emplace_back();
+        if(!_sources.empty()) (this->*addSource)("#line 1 " + std::to_string((_sources.size()+1)/2) + '\n');
+        else (this->*addSource)({});
 
-        _sources.push_back(std::move(source));
+        (this->*addSource)(std::move(source));
     }
 
     return *this;
 }
 
+void Shader::addSourceImplementationDefault(std::string source) {
+    _sources.push_back(std::move(source));
+}
+
+#if defined(CORRADE_TARGET_EMSCRIPTEN) && defined(__EMSCRIPTEN_PTHREADS__)
+void Shader::addSourceImplementationEmscriptenPthread(std::string source) {
+    /* See the "emscripten-pthreads-broken-unicode-shader-sources"
+       workaround description for details */
+    for(char& c: source) if(c < 0) c = ' ';
+    _sources.push_back(std::move(source));
+}
+#endif
+
 Shader& Shader::addFile(const std::string& filename) {
     CORRADE_ASSERT(Utility::Directory::fileExists(filename),
         "Shader file " << '\'' + filename + '\'' << " cannot be read.", *this);

src/Magnum/Shader.h

@@ -39,6 +39,8 @@
 
 namespace Magnum {
 
+namespace Implementation { struct ShaderState; }
+
 /**
 @brief Shader
 
@@ -50,6 +52,8 @@ Shader limits and implementation-defined values (such as @ref maxUniformComponen
 are cached, so repeated queries don't result in repeated @fn_gl{Get} calls.
  */
 class MAGNUM_EXPORT Shader: public AbstractObject {
+    friend Implementation::ShaderState;
+
     public:
         /**
          * @brief Shader type
@@ -615,6 +619,11 @@ class MAGNUM_EXPORT Shader: public AbstractObject {
     private:
         Shader& setLabelInternal(Containers::ArrayView<const char> label);
 
+        void MAGNUM_LOCAL addSourceImplementationDefault(std::string source);
+        #if defined(CORRADE_TARGET_EMSCRIPTEN) && defined(__EMSCRIPTEN_PTHREADS__)
+        void MAGNUM_LOCAL addSourceImplementationEmscriptenPthread(std::string source);
+        #endif
+
         Type _type;
         GLuint _id;