Splits prelude into WTSE/Formula and adds it to WTSE

src/common/LuaSupport.cpp

@@ -175,10 +175,10 @@ bool Surge::LuaSupport::setSurgeFunctionEnvironment(lua_State *L)
     lua_setfield(L, eidx, "print");
 
     // add global tables
-    lua_getglobal(L, "surge");
-    lua_setfield(L, eidx, "surge");
-    lua_getglobal(L, "shared");
-    lua_setfield(L, eidx, "shared");
+    lua_getglobal(L, surgeTableName);
+    lua_setfield(L, eidx, surgeTableName);
+    lua_getglobal(L, sharedTableName);
+    lua_setfield(L, eidx, sharedTableName);
 
     // add whitelisted functions and modules
     std::vector<std::string> sandboxWhitelist = {"pairs",    "ipairs",       "unpack",
@@ -271,21 +271,32 @@ bool Surge::LuaSupport::setSurgeFunctionEnvironment(lua_State *L)
     return true;
 }
 
-bool Surge::LuaSupport::loadSurgePrelude(lua_State *s, const char *surgeTableName)
+bool Surge::LuaSupport::loadSurgePrelude(lua_State *L, const std::string &lua_script)
 {
 #if HAS_LUA
-    auto guard = SGLD("loadPrologue", s);
-    // now load the surge library
-    auto &lua_script = LuaSources::surge_prelude;
+    auto guard = SGLD("loadSurgePrelude", L);
+    // Load the specified Lua script into the global table "surge"
     auto lua_size = lua_script.size();
-    auto load_stat = luaL_loadbuffer(s, lua_script.c_str(), lua_size, lua_script.c_str());
-    auto pcall = lua_pcall(s, 0, 1, 0);
-    lua_setglobal(s, surgeTableName);
+    auto status = luaL_loadbuffer(L, lua_script.c_str(), lua_size, lua_script.c_str());
+    if (status != 0)
+    {
+        std::cout << "Error: Failed to load Lua file [ " << lua_script.c_str() << " ]" << std::endl;
+        return false;
+    }
+    auto pcall = lua_pcall(L, 0, 1, 0);
+    if (pcall != 0)
+    {
+        std::cout << "Error: Failed to run Lua file [ " << lua_script.c_str() << " ]" << std::endl;
+        return false;
+    }
+    lua_setglobal(L, surgeTableName);
 #endif
     return true;
 }
 
-std::string Surge::LuaSupport::getSurgePrelude() { return LuaSources::surge_prelude; }
+std::string Surge::LuaSupport::getFormulaPrelude() { return LuaSources::formula_prelude; }
+
+std::string Surge::LuaSupport::getWTSEPrelude() { return LuaSources::wtse_prelude; }
 
 Surge::LuaSupport::SGLD::~SGLD()
 {

src/common/LuaSupport.h

@@ -85,15 +85,20 @@ int parseStringDefiningMultipleFunctions(lua_State *s, const std::string &defini
 bool setSurgeFunctionEnvironment(lua_State *s);
 
 /*
- * Call this function with a LUA state and a tablename and it will introduce the global
- * 'surge' which is the surge prelude
+ * Call this function with a LUA state, the std::string at Surge::LuaSources and it will load the
+ * prelude in the table "surge"
  */
-bool loadSurgePrelude(lua_State *s, const char *surgeTableName);
+bool loadSurgePrelude(lua_State *s, const std::string &lua_script);
 
 /*
- * Call this function to get a string representation of the prelude
+ * Call this function to get a string representation of the Formula prelude
  */
-std::string getSurgePrelude();
+std::string getFormulaPrelude();
+
+/*
+ * Call this function to get a string representation of the WTSE prelude
+ */
+std::string getWTSEPrelude();
 
 /*
  * A little leak debugger. Make this on your stack and if you exit the
@@ -118,6 +123,12 @@ struct SGLD
     int top;
 };
 
+/*
+ * Global table names
+ */
+static constexpr const char *surgeTableName{"surge"};
+static constexpr const char *sharedTableName{"shared"};
+
 } // namespace LuaSupport
 } // namespace Surge
 

src/common/dsp/WavetableScriptEvaluator.cpp

@@ -22,6 +22,7 @@
 
 #include "WavetableScriptEvaluator.h"
 #include "LuaSupport.h"
+#include "lua/LuaSources.h"
 
 namespace Surge
 {
@@ -42,6 +43,10 @@ std::vector<float> evaluateScriptAtFrame(SurgeStorage *storage, const std::strin
     auto values = std::vector<float>();
 
     auto wg = Surge::LuaSupport::SGLD("WavetableScript::evaluate", L);
+
+    // Load the WTSE prelude
+    Surge::LuaSupport::loadSurgePrelude(L, Surge::LuaSources::wtse_prelude);
+
     std::string emsg;
     auto res = Surge::LuaSupport::parseStringDefiningFunction(L, eqn.c_str(), "generate", emsg);
     if (res)

src/common/dsp/modulators/FormulaModulationHelper.cpp

@@ -27,6 +27,7 @@
 #include <thread>
 #include <functional>
 #include "fmt/core.h"
+#include "lua/LuaSources.h"
 
 namespace Surge
 {
@@ -81,12 +82,13 @@ bool prepareForEvaluation(SurgeStorage *storage, FormulaModulatorStorage *fs, Ev
 
     if (firstTimeThrough)
     {
-        // setup shared table
+        // Setup shared table
         lua_newtable(s.L);
         lua_setglobal(s.L, sharedTableName);
 
-        // setup prelude
-        Surge::LuaSupport::loadSurgePrelude(s.L, surgeTableName);
+        // Load the Formula prelude
+        Surge::LuaSupport::loadSurgePrelude(s.L, Surge::LuaSources::formula_prelude);
+
         auto reserved0 = std::string(R"FN(
 function surge_reserved_formula_error_stub(m)
     return 0;

src/common/dsp/modulators/FormulaModulationHelper.h

@@ -44,7 +44,6 @@ struct GlobalData
 };
 
 static constexpr int max_formula_outputs{max_lfo_indices};
-static constexpr const char *surgeTableName{"surge"};
 static constexpr const char *sharedTableName{"shared"};
 
 struct EvaluatorState

src/lua/CMakeLists.txt

@@ -7,21 +7,23 @@ project(surge-lua-src)
 # 1. Create myscript.lua
 # 2. Add it to the list below
 # 3. myscript.lua is now a std::string at Surge::LuaSources::myscript
+
 set(lua_sources
-  surge_prelude.lua
-  surge_prelude_test.lua
-  )
+  formula_prelude.lua
+  formula_prelude_test.lua
+  wtse_prelude.lua
+)
 
 set(generated_sources
   ${CMAKE_CURRENT_BINARY_DIR}/LuaSources.cpp
   ${CMAKE_CURRENT_BINARY_DIR}/include/lua/LuaSources.h
-  )
+)
 
 add_library(${PROJECT_NAME} ${generated_sources})
 
 add_custom_command(OUTPUT ${generated_sources}
   COMMAND ${CMAKE_COMMAND} -P lua2cpp.cmake ${CMAKE_CURRENT_BINARY_DIR} LuaSources.cpp lua/LuaSources.h Surge::LuaSources ${lua_sources}
   WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
   DEPENDS lua2cpp.cmake ${lua_sources}
-  )
+)
 target_include_directories(${PROJECT_NAME} PUBLIC ${CMAKE_CURRENT_BINARY_DIR}/include)

src/lua/wtse_prelude.lua

@@ -0,0 +1,118 @@
+-- This document is loaded in each Surge XT session and provides a set of built-in helpers
+-- we've found handy when generating wavetables. Consider it as a library of functions.
+-- For each official update of Surge XT we will freeze the state of the prelude as stable
+-- and not break included functions after that.
+--
+-- If you have ideas for other useful functions that could be added here, by all means
+-- contact us over GitHub or Discord and let us know!
+
+
+local surge = {}
+
+
+--- MATH FUNCTIONS ---
+
+
+-- parity function returns 0 for even numbers and 1 for odd numbers
+function math.parity(x)
+    return (x % 2 == 1 and 1) or 0
+end
+
+-- signum function returns -1 for negative numbers, 0 for zero, 1 for positive numbers
+function math.sgn(x)
+    return (x > 0 and 1) or (x < 0 and -1) or 0
+end
+
+-- sign function returns -1 for negative numbers and 1 for positive numbers or zero
+function math.sign(x)
+    return (x < 0 and -1) or 1
+end
+
+-- linearly interpolates value from in range to out range
+function math.rescale(value, in_min, in_max, out_min, out_max)
+    return (((value - in_min) * (out_max - out_min)) / (in_max - in_min)) + out_min
+end
+
+-- returns the norm of the two components (hypotenuse)
+function math.norm(a, b)
+    return math.sqrt(a ^ 2 + b ^ 2)
+end
+
+-- returns the absolute range between the two numbers
+function math.range(a, b)
+    return math.abs(a - b)
+end
+
+
+-- WTSE MATH FUNCTIONS - NON-FINAL AND WIP
+
+
+-- returns a table with the cumulative product of the elements in the input table
+function math.cumprod(t)
+    local o = {}
+    o[1] = t[1]
+    for i = 2, #t do
+        o[i] = o[i - 1] * t[i]
+    end
+    return o
+end
+
+-- returns a table with the cumulative sum of the elements in the input table
+function math.cumsum(t)
+    local o = {}
+    o[1] = t[1]
+    for i = 2, #t do
+        o[i] = o[i - 1] + t[i]
+    end
+    return o
+end
+
+-- returns a table containing num_points linearly spaced numbers from start_point to end_point
+function math.linspace(start_point, end_point, num_points)
+    local t = {}
+    local step = (end_point - start_point) / (num_points - 1)
+    for i = 1, num_points do
+        t[i] = start_point + (i - 1) * step
+    end
+    return t
+end
+
+-- returns a table containing num_points logarithmically spaced numbers from 10^start_point to 10^end_point
+function math.logspace(start_point, end_point, num_points)
+    local t = {}
+    local step = (end_point - start_point) / (num_points - 1)
+    for i = 1, num_points do
+        local exponent = start_point + (i - 1) * step
+        t[i] = 10 ^ exponent
+    end
+    return t
+end
+
+-- returns the maximum absolute value found in the input table
+function math.maxAbsFromTable(t)
+    local o = 0
+    for i = 1, #t do
+            local a = abs(t[i])
+            if a > o then o = a end
+    end
+    return o
+end
+
+-- returns the normalized sinc function for a table of input values
+function math.sinc(t)
+    local o = {}
+    for i, x in ipairs(t) do
+        if x == 0 then
+            o[i] = 1
+        else
+            o[i] = math.sin(math.pi * x) / (math.pi * x)
+        end
+    end
+    return o
+end
+
+
+--- END ---
+
+
+return surge

src/surge-testrunner/UnitTestsLUA.cpp

@@ -159,12 +159,11 @@ TEST_CASE("Surge Prelude", "[lua]")
         REQUIRE(L);
         luaL_openlibs(L);
 
-        static constexpr const char *surgeTableName{"surge"};
-        REQUIRE(Surge::LuaSupport::loadSurgePrelude(L, surgeTableName));
+        REQUIRE(Surge::LuaSupport::loadSurgePrelude(L, Surge::LuaSources::formula_prelude));
 
         std::string emsg;
         REQUIRE(Surge::LuaSupport::parseStringDefiningFunction(
-            L, Surge::LuaSources::surge_prelude_test, "test", emsg));
+            L, Surge::LuaSources::formula_prelude_test, "test", emsg));
         Surge::LuaSupport::setSurgeFunctionEnvironment(L);
 
         auto pcall = lua_pcall(L, 0, 1, 0);

src/surge-xt/gui/overlays/LuaEditors.cpp

@@ -744,7 +744,7 @@ FormulaModulatorEditor::FormulaModulatorEditor(SurgeGUIEditor *ed, SurgeStorage
     mainDocument->insertText(0, fs->formulaString);
 
     preludeDocument = std::make_unique<juce::CodeDocument>();
-    preludeDocument->insertText(0, Surge::LuaSupport::getSurgePrelude());
+    preludeDocument->insertText(0, Surge::LuaSupport::getFormulaPrelude());
 
     preludeDisplay = std::make_unique<SurgeCodeEditorComponent>(*preludeDocument, tokenizer.get());
     preludeDisplay->setTabSize(4, true);
@@ -1282,9 +1282,8 @@ WavetableScriptEditor::WavetableScriptEditor(SurgeGUIEditor *ed, SurgeStorage *s
         mainDocument->insertText(0, osc->wavetable_formula);
     }
 
-    // FIXME: split prelude into Formula and WTSE
     preludeDocument = std::make_unique<juce::CodeDocument>();
-    preludeDocument->insertText(0, Surge::LuaSupport::getSurgePrelude());
+    preludeDocument->insertText(0, Surge::LuaSupport::getWTSEPrelude());
 
     preludeDisplay = std::make_unique<SurgeCodeEditorComponent>(*preludeDocument, tokenizer.get());
     preludeDisplay->setTabSize(4, true);