GL: deprecate list-taking Shader::compile() and ShaderProgram::link().

There's no reason for those to exist anymore -- origiinally they were
added in a hopeful attempt to make use of parallel shader compilation,
but in practice that meant compiling at most two or three shaders at
once and still stalling until that was done, so not that great at all.
The new APIs provide much better opportunities for parallelism.

Fun fact:

    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());

is actually one character shorter than

    CORRADE_INTERNAL_ASSERT_OUTPUT(GL::Shader::compile({vert, frag}));

so not even typing convenience would be a reason to keep these.

doc/changelog.dox

@@ -821,6 +821,16 @@ See also:
     @ref DebugTools::FrameProfilerGL. The new name plays better with IDE
     autocompletion and makes the GL-specific class appear next to the
     API-independent base in alphabetically sorted lists.
+-   List-taking @cpp GL::Shader::compile() @ce and
+    @cpp GL::AbstractShaderProgram::link() @ce functions are deprecated in
+    favor of new @ref GL::Shader::submitCompile(),
+    @relativeref{GL::Shader,checkCompile()},
+    @ref GL::AbstractShaderProgram::submitLink() and
+    @relativeref{GL::AbstractShaderProgram,checkLink()} APIs. These were
+    originally meant to make use of parallel shader compilation, but in
+    practice that meant compiling at most two or three shaders at once. The new
+    API allows for much larger parallelism as well as an ability to query
+    completion status.
 -   @cpp Shaders::DistanceFieldVector @ce, @cpp Shaders::Flat @ce,
     @cpp Shaders::Generic @ce, @cpp Shaders::MeshVisualizer2D @ce,
     @cpp Shaders::MeshVisualizer3D @ce, @cpp Shaders::Phong @ce,

doc/snippets/MagnumGL.cpp

@@ -147,8 +147,8 @@ explicit MyShader() {
     vert.addFile("MyShader.vert");
     frag.addFile("MyShader.frag");
 
-    /* Invoke parallel compilation for best performance */
-    CORRADE_INTERNAL_ASSERT_OUTPUT(GL::Shader::compile({vert, frag}));
+    /* Compile them */
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     /* Attach the shaders */
     attachShaders({vert, frag});

src/Magnum/DebugTools/TextureImage.cpp

@@ -87,7 +87,7 @@ FloatReinterpretShader::FloatReinterpretShader() {
     vert.addSource(rs.getString("TextureImage.vert"));
     frag.addSource(rs.getString("TextureImage.frag"));
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(GL::Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
     attachShaders({vert, frag});
 
     if(!GL::Context::current().isExtensionSupported<GL::Extensions::MAGNUM::shader_vertex_id>()) {

src/Magnum/GL/AbstractShaderProgram.cpp

@@ -586,7 +586,10 @@ void AbstractShaderProgram::transformFeedbackVaryingsImplementationDanglingWorka
 #endif
 #endif
 
-bool AbstractShaderProgram::link() { return link({*this}); }
+bool AbstractShaderProgram::link() {
+    submitLink();
+    return checkLink({});
+}
 
 void AbstractShaderProgram::submitLink() {
     glLinkProgram(_id);
@@ -637,12 +640,14 @@ bool AbstractShaderProgram::checkLink(const Containers::Iterable<Shader> shaders
     return success;
 }
 
+#ifdef MAGNUM_BUILD_DEPRECATED
 bool AbstractShaderProgram::link(std::initializer_list<Containers::Reference<AbstractShaderProgram>> shaders) {
     for(AbstractShaderProgram& shader: shaders) shader.submitLink();
     bool allSuccess = true;
     for(AbstractShaderProgram& shader: shaders) allSuccess = allSuccess && shader.checkLink({});
     return allSuccess;
 }
+#endif
 
 bool AbstractShaderProgram::isLinkFinished() {
     GLint success;

src/Magnum/GL/AbstractShaderProgram.h

@@ -43,6 +43,7 @@
 #endif
 
 #ifdef MAGNUM_BUILD_DEPRECATED
+#include <Corrade/Utility/Macros.h>
 /* For label() / setLabel(), which used to be a std::string */
 #include <Corrade/Containers/StringStl.h>
 #endif
@@ -1345,15 +1346,22 @@ class MAGNUM_GL_EXPORT AbstractShaderProgram: public AbstractObject {
         bool isLinkFinished();
 
     protected:
-        /** @brief Link the shaders
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /**
+         * @brief Link multiple shaders simultaenously
+         * @m_deprecated_since_latest Originally meant to batch multiple link
+         *      operations together in a way that allowed the driver to perform
+         *      the linking in multiple threads. Superseded by @ref submitLink()
+         *      and @ref checkLink(), use either those or the zero-argument
+         *      @ref link() instead. See @ref GL-AbstractShaderProgram-async
+         *      for more information.
          *
          * Calls @ref submitLink() on all shaders first, then @ref checkLink().
          * Returns @cpp false @ce if linking of any shader failed, @cpp true @ce
-         * if everything succeeded. The operation is batched in a
-         * way that allows the driver to link multiple shaders simultaneously
-         * (i.e. in multiple threads).
+         * if everything succeeded.
          */
-        static bool link(std::initializer_list<Containers::Reference<AbstractShaderProgram>> shaders);
+        static CORRADE_DEPRECATED("use either submitLink() and checkLink() or the zero-argument link() instead") bool link(std::initializer_list<Containers::Reference<AbstractShaderProgram>> shaders);
+        #endif
 
         #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
         /**

src/Magnum/GL/Shader.cpp

@@ -27,7 +27,9 @@
 #include "Shader.h"
 
 #include <Corrade/Containers/Array.h>
+#ifdef MAGNUM_BUILD_DEPRECATED
 #include <Corrade/Containers/Reference.h>
+#endif
 #ifndef MAGNUM_TARGET_WEBGL
 #include <Corrade/Containers/String.h>
 #endif
@@ -748,7 +750,10 @@ Shader& Shader::addFile(const std::string& filename) {
     return *this;
 }
 
-bool Shader::compile() { return compile({*this}); }
+bool Shader::compile() {
+    submitCompile();
+    return checkCompile();
+}
 
 void Shader::submitCompile() {
     CORRADE_ASSERT(_sources.size() > 1, "GL::Shader::compile(): no files added", );
@@ -808,6 +813,7 @@ bool Shader::checkCompile() {
     return success;
 }
 
+#ifdef MAGNUM_BUILD_DEPRECATED
 bool Shader::compile(std::initializer_list<Containers::Reference<Shader>> shaders) {
     /* Invoke (possibly parallel) compilation on all shaders */
     for(Shader& shader: shaders) shader.submitCompile();
@@ -815,6 +821,7 @@ bool Shader::compile(std::initializer_list<Containers::Reference<Shader>> shader
     for(Shader& shader: shaders) allSuccess = allSuccess && shader.checkCompile();
     return allSuccess;
 }
+#endif
 
 bool Shader::isCompileFinished() {
     GLint success;

src/Magnum/GL/Shader.h

@@ -39,6 +39,7 @@
 #include "Magnum/GL/GL.h"
 
 #ifdef MAGNUM_BUILD_DEPRECATED
+#include <Corrade/Utility/Macros.h>
 /* For label() / setLabel(), which used to be a std::string. Not ideal for the
    return type, but at least something. */
 #include <Corrade/Containers/StringStl.h>
@@ -508,16 +509,22 @@ class MAGNUM_GL_EXPORT Shader: public AbstractObject {
         static Int maxCombinedUniformComponents(Type type);
         #endif
 
+        #ifdef MAGNUM_BUILD_DEPRECATED
         /**
          * @brief Compile multiple shaders simultaneously
-         *
-         * Calls @ref submitCompile() on all shaders first, then @ref checkCompile().
-         * Returns @cpp false @ce if compilation of any shader failed,
-         * @cpp true @ce if everything succeeded. The operation is batched in a way that
-         * allows the driver to perform multiple compilations simultaneously
-         * (i.e. in multiple threads).
-         */
-        static bool compile(std::initializer_list<Containers::Reference<Shader>> shaders);
+         * @m_deprecated_since_latest Originally meant to batch multiple
+         *      compile operations together in a way that allowed the driver to
+         *      perform the compilation in multiple threads. Superseded by
+         *      @ref submitCompile() and @ref checkCompile(), use either those
+         *      or the zero-argument @ref compile() instead. See
+         *      @ref GL-AbstractShaderProgram-async for more information.
+         *
+         * Calls @ref submitCompile() on all shaders first, then
+         * @ref checkCompile(). Returns @cpp false @ce if compilation of any
+         * shader failed, @cpp true @ce if everything succeeded.
+         */
+        static CORRADE_DEPRECATED("use either submitCompile() and checkCompile() or the zero-argument compile() instead") bool compile(std::initializer_list<Containers::Reference<Shader>> shaders);
+        #endif
 
         /**
          * @brief Constructor

src/Magnum/GL/Test/AbstractShaderProgramGLTest.cpp

@@ -652,7 +652,8 @@ void AbstractShaderProgramGLTest::uniformNotFound() {
         #endif
         );
 
-    CORRADE_VERIFY(Shader::compile({vert, frag}));
+    CORRADE_VERIFY(vert.compile() && frag.compile());
+
     program.attachShaders({vert, frag});
     CORRADE_VERIFY(program.link());
 
@@ -702,10 +703,10 @@ MyShader::MyShader() {
         Version::GLES200
         #endif
         , Shader::Type::Fragment);
-    vert.addSource(rs.getString("MyShader.vert"));
-    frag.addSource(rs.getString("MyShader.frag"));
-
-    Shader::compile({vert, frag});
+    vert.addSource(rs.getString("MyShader.vert"))
+        .compile();
+    frag.addSource(rs.getString("MyShader.frag"))
+        .compile();
 
     attachShaders({vert, frag});
 
@@ -786,10 +787,10 @@ MyDoubleShader::MyDoubleShader() {
 
     Shader vert(Version::GL320, Shader::Type::Vertex);
     Shader frag(Version::GL320, Shader::Type::Fragment);
-    vert.addSource(rs.getString("MyDoubleShader.vert"));
-    frag.addSource(rs.getString("MyDoubleShader.frag"));
-
-    Shader::compile({vert, frag});
+    vert.addSource(rs.getString("MyDoubleShader.vert"))
+        .compile();
+    frag.addSource(rs.getString("MyDoubleShader.frag"))
+        .compile();
 
     attachShaders({vert, frag});
 
@@ -948,8 +949,8 @@ void AbstractShaderProgramGLTest::uniformBlockIndexNotFound() {
     vert.addSource("void main() { gl_Position = vec4(0.0); }");
     frag.addSource("out lowp vec4 color;\n"
                    "void main() { color = vec4(1.0); }");
+    CORRADE_VERIFY(vert.compile() && frag.compile());
 
-    CORRADE_VERIFY(Shader::compile({vert, frag}));
     program.attachShaders({vert, frag});
     CORRADE_VERIFY(program.link());
 
@@ -989,10 +990,11 @@ UniformBlockShader::UniformBlockShader() {
         Version::GLES300
         #endif
         , Shader::Type::Fragment);
-    vert.addSource(rs.getString("UniformBlockShader.vert"));
-    frag.addSource(rs.getString("UniformBlockShader.frag"));
+    vert.addSource(rs.getString("UniformBlockShader.vert"))
+        .compile();
+    frag.addSource(rs.getString("UniformBlockShader.frag"))
+        .compile();
 
-    Shader::compile({vert, frag});
     attachShaders({vert, frag});
 
     link();

src/Magnum/GL/Test/MeshGLTest.cpp

@@ -1023,7 +1023,7 @@ FloatShader::FloatShader(const std::string& type, const std::string& conversion)
         "#endif\n"
         "void main() { result = " + conversion + "; }\n");
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});
 
@@ -1065,7 +1065,7 @@ IntegerShader::IntegerShader(const std::string& type) {
                    "out mediump " + type + " result;\n"
                    "void main() { result = valueInterpolated; }\n");
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});
 
@@ -1100,7 +1100,7 @@ DoubleShader::DoubleShader(const std::string& type, const std::string& outputTyp
                    "out " + outputType + " result;\n"
                    "void main() { result = valueInterpolated; }\n");
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});
 
@@ -2147,7 +2147,7 @@ MultipleShader::MultipleShader() {
         "#endif\n"
         "void main() { result = valueInterpolated; }\n");
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});
 
@@ -3836,7 +3836,7 @@ MultiDrawShader::MultiDrawShader(bool vertexId, bool drawId) {
         "#endif\n"
         "void main() { result.r = valueInterpolated; }\n");
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});
 
@@ -4641,7 +4641,7 @@ MultiDrawInstancedShader::MultiDrawInstancedShader(bool vertexId, bool drawId
         "#endif\n"
         "void main() { result.r = valueInterpolated; }\n");
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});
 

src/Magnum/GL/Test/RendererGLTest.cpp

@@ -203,7 +203,7 @@ void RendererGLTest::pointCoord() {
                     color = vec4(gl_PointCoord.x, gl_PointCoord.y, 0.0, 1.0);
                 })GLSL");
 
-            CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+            CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
             attachShaders({vert, frag});
 

src/Magnum/GL/Test/SampleQueryGLTest.cpp

@@ -207,7 +207,7 @@ MyShader::MyShader() {
         "    color = vec4(1.0, 1.0, 1.0, 1.0);\n"
         "}\n");
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});
 

src/Magnum/GL/Test/TransformFeedbackGLTest.cpp

@@ -635,7 +635,8 @@ void TransformFeedbackGLTest::draw() {
             else geom.addSource(
                 "    EmitVertex();\n");
             geom.addSource("}\n");
-            CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, geom}));
+            CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && geom.compile());
+
             attachShaders({vert, geom});
             setTransformFeedbackOutputs({"geomOutput"}, TransformFeedbackBufferMode::SeparateAttributes);
             CORRADE_INTERNAL_ASSERT_OUTPUT(link());
@@ -696,8 +697,8 @@ void TransformFeedbackGLTest::draw() {
                 "void main() {\n"
                 "    outputData = interleaved.x + 2*interleaved.y;\n"
                 "}\n");
+            CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
-            CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));
             attachShaders({vert, frag});
             bindAttributeLocation(Input::Location, "inputData");
             CORRADE_INTERNAL_ASSERT_OUTPUT(link());

src/Magnum/MeshTools/Test/FullScreenTriangleGLTest.cpp

@@ -102,7 +102,7 @@ void main() {
 }
             )");
 
-            CORRADE_INTERNAL_ASSERT_OUTPUT(GL::Shader::compile({vert, frag}));
+            CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
             attachShaders({vert, frag});
 

src/Magnum/TextureTools/DistanceField.cpp

@@ -104,7 +104,7 @@ DistanceFieldShader::DistanceFieldShader(const UnsignedInt radius) {
     frag.addSource(Utility::formatString("#define RADIUS {}\n", radius))
         .addSource(rs.getString("DistanceFieldShader.frag"));
 
-    CORRADE_INTERNAL_ASSERT_OUTPUT(GL::Shader::compile({vert, frag}));
+    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
 
     attachShaders({vert, frag});