Headless Surge working

The gui is well separable from the patch/parameter/dsp/synth
code so a headless mode should have been readily doable at
any time. With this commit, it is done. This shows a small
example of setting up and running a 2 oscillator detuned saw
configuration of surge.

On Linux, one VSTGUI symbol is still pulled in for a reason
I can't determine, so introduce it in a fixes file which we
need to address in a future issue if/as we develop headless.

Closes surge-synthesizer#499.

.gitignore

@@ -48,6 +48,7 @@ Surge.xcworkspace/
 surge-au.xcodeproj/
 surge-vst2.xcodeproj/
 surge-vst3.xcodeproj/
+surge-headless.xcodeproj/
 products/
 installer_mac/installer
 installer_mac/*.dmg

build-osx.sh

@@ -38,6 +38,7 @@ Commands are:
         --build-validate-au      Build and install the audio unit then validate it
         --build-install-vst2     Build and install only the VST2
         --build-install-vst3     Build and install only the VST3
+        --build-headless         Build the headless application
 
         --package                Creates a .pkg file from current built state in products
         --clean-and-package      Cleans everything; runs all the builds; makes an installer; drops it in products
@@ -181,6 +182,7 @@ run_all_builds()
 
     run_build "vst3"
     run_build "au"
+    run_build "headless"
 }
 
 run_install_local()
@@ -239,6 +241,7 @@ run_clean_builds()
 
     run_clean "vst3"
     run_clean "au"
+    run_clean "headless"
 }
 
 run_clean_all()
@@ -320,6 +323,10 @@ case $command in
     --build-install-vst3)
         run_build_install_vst3
         ;;
+    --build-headless)
+        run_premake_if
+        run_build "headless"
+        ;;
     --clean)
         run_clean_builds
         ;;

premake5.lua

@@ -662,3 +662,71 @@ if (os.istarget("linux")) then
     configuration { "Release" }
     targetdir "target/app/Release"
 end
+
+-- HEADLESS APP
+
+project "surge-headless"
+kind "ConsoleApp"
+
+defines
+{
+    "TARGET_HEADLESS=1"
+}
+
+plugincommon()
+
+files {
+    "src/headless/main.cpp",
+    "src/headless/DisplayInfoHeadless.cpp",
+    "src/headless/UserInteractionsHeadless.cpp",
+    "src/headless/LinkFixesHeadless.cpp"
+    }
+
+excludes {
+    "src/common/gui/*"
+}
+
+includedirs {
+    "src/headless"
+}
+
+configuration { "Debug" }
+targetdir "target/headless/Debug"
+targetsuffix "-Debug"
+
+configuration { "Release" }
+targetdir "target/headless/Release"
+
+configuration {}
+
+if (os.istarget("macosx")) then
+       excludes{
+           VSTGUI .. "vstgui_mac.mm",
+           VSTGUI .. "vstgui_uidescription_mac.mm",
+           "src/mac/DisplayInfoMac.mm",
+           "src/mac/UserInteractionsMac.cpp",
+       }
+end
+
+if (os.istarget("windows")) then
+       excludes{
+           VSTGUI .. "vstgui_win32.cpp",
+           VSTGUI .. "vstgui_uidescription_win32.cpp",
+           "src/windows/DisplayInfoWin.cpp",
+           "src/windows/UserInteractionsWin.cpp",
+       }
+end
+
+if (os.istarget("linux")) then
+    excludes {
+            VSTGUI .. "vstgui.cpp",
+            VSTGUI .. "lib/platform/linux/**.cpp",
+            VSTGUI .. "lib/platform/common/genericoptionmenu.cpp",
+            VSTGUI .. "lib/platform/common/generictextedit.cpp",
+           "src/linux/DisplayInfoLinux.cpp",
+           "src/linux/UserInteractionsLinux.cpp",
+    }
+end
+
+
+

src/common/SurgeSynthesizer.cpp

@@ -10,6 +10,7 @@
 #include <windows.h>
 #include <process.h>
 #endif
+
 #if TARGET_AUDIOUNIT
 #include "aulayer.h"
 #include "vstgui/plugin-bindings/plugguieditor.h"
@@ -19,8 +20,11 @@
 #elif TARGET_APP
 #include "PluginLayer.h"
 #include "vstgui/plugin-bindings/plugguieditor.h"
+#elif TARGET_HEADLESS
+#include "HeadlessPluginLayerProxy.h" // from src/headless
 #else
 #include "Vst2PluginInstance.h"
+
 #if LINUX
 #include "../linux/linux-aeffguieditor.h"
 #else
@@ -669,6 +673,8 @@ void SurgeSynthesizer::sendParameterAutomation(long index, float value)
       getParent()->setParameterAutomated(externalparam, value);
 #elif TARGET_APP
       getParent()->sendParameterAutomation(externalparam, value);
+#elif TARGET_HEADLESS
+      // NO OP
 #else
       getParent()->setParameterAutomated(externalparam, value);
 #endif

src/common/SurgeSynthesizer.h

@@ -21,6 +21,9 @@ typedef SurgeVst3Processor PluginLayer;
 #elif TARGET_VST2
 class Vst2PluginInstance;
 using PluginLayer = Vst2PluginInstance;
+#elif TARGET_HEADLESS
+class HeadlessPluginLayerProxy;
+using PluginLayer = HeadlessPluginLayerProxy;
 #else
 class PluginLayer;
 #endif

src/headless/DisplayInfoHeadless.cpp

@@ -0,0 +1,22 @@
+#include "DisplayInfo.h"
+#include "UserInteractions.h"
+
+namespace Surge
+{
+namespace GUI
+{
+
+using namespace VSTGUI;
+
+float getDisplayBackingScaleFactor(CFrame *)
+{
+    return 1.0;
+}
+
+CRect getScreenDimensions(CFrame *)
+{
+    return CRect(CPoint(0,0), CPoint(1024,768));
+}
+
+}
+}

src/headless/HeadlessPluginLayerProxy.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <iostream>
+#include <iomanip>
+
+class HeadlessPluginLayerProxy
+{
+public:
+    void updateDisplay()
+    {
+        std::cerr << "HeadlessPluginLayerProxy::updateDisplay" << std::endl;
+    }
+
+};

src/headless/LinkFixesHeadless.cpp

@@ -0,0 +1,14 @@
+/*
+** There are a few symbols which on Linux currently get linked
+** for a very difficult to determine reason. We should fix this,
+** but for the meantime lets add this file to patch the link
+** errors
+*/
+#if LINUX
+namespace VSTGUI
+{
+void doAssert(const char*, const char*, const char*)
+{
+}
+}
+#endif

src/headless/UserInteractionsHeadless.cpp

@@ -0,0 +1,37 @@
+#include "UserInteractions.h"
+#include <iostream>
+#include <iomanip>
+
+namespace Surge
+{
+    namespace UserInteractions
+    {
+        void promptError(const Surge::Error &e)
+        {
+            promptError(e.getMessage(), e.getTitle());
+        }
+
+        void promptError(const std::string &message,
+                         const std::string &title)
+        {
+            std::cerr << "Surge Error\n"
+                      << title << "\n"
+                      << message << "\n" << std::flush;
+        }
+
+        UserInteractions::MessageResult promptOKCancel(const std::string &message,
+                                                       const std::string &title)
+        {
+            std::cerr << "Surge OkCancel\n"
+                      << title << "\n"
+                      << message << "\n" 
+                      << "Returning CANCEL" << std::flush;
+            return UserInteractions::CANCEL;
+        }
+
+        void openURL(const std::string &url)
+        {
+        }
+    };
+};
+

src/headless/main.cpp

@@ -0,0 +1,68 @@
+#include <iostream>
+#include <iomanip>
+
+#include "SurgeSynthesizer.h"
+
+#include "HeadlessPluginLayerProxy.h"
+
+int main(int argc, char** argv)
+{
+    std::cout << "Surge Headless Mode" << std::endl;
+
+    HeadlessPluginLayerProxy *parent = new HeadlessPluginLayerProxy();
+    std::unique_ptr<SurgeSynthesizer> surge(new SurgeSynthesizer(parent));
+    surge->setSamplerate(44100);
+
+    /*
+    ** Change a parameter in the scene. Do this by traversing the 
+    ** graph in the current patch (which is in surge->storage).
+    **
+    ** Clearly a more fulsome headless API would provide wrappers around
+    ** this for common activities. This sets up a pair of detuned saw waves
+    ** both active.
+    */
+    surge->storage.getPatch().scene[0].osc[0].pitch.set_value_f01(4);
+    surge->storage.getPatch().scene[0].mute_o2.set_value_f01(0,true);
+    surge->storage.getPatch().scene[0].osc[1].pitch.set_value_f01(1);
+
+    /*
+    ** Play a note. channel, note, velocity, detune
+    */
+    surge->playNote((char)0, (char)60, (char)100, 0); 
+
+    /*
+    ** Strip off some processing first to avoid the attach transient
+    */
+    for(auto i=0; i<20; ++i) surge->process();
+
+    /*
+    ** Then run the sampler
+    */
+    int blockCount = 30;
+    int overSample = 8;
+    float overS = 0;
+    int sampleCount = 0;
+    for(auto i=0; i<blockCount; ++i )
+    {
+        surge->process();
+
+        for (int sm=0;sm<BLOCK_SIZE;++sm)
+        {
+            float avgOut = 0;
+            for (int oi=0; oi<surge->getNumOutputs(); ++oi)
+            {
+                avgOut += surge->output[oi][sm];
+            }
+
+            overS += avgOut;
+            if (((sampleCount-1)%overSample) == 0)
+            {
+                overS /= overSample;
+                int gWidth = (int)((overS + 1)*30);
+                std::cout << "Sample: " << std::setw( 15 ) << overS << std::setw(gWidth) << "X" << std::endl;;
+            }
+            sampleCount ++;
+
+        }
+    }
+}