Make the _qt_order input location configurable

Change-Id: Id746ed3b6eefa7d4de3bff663c61c57a35052d1a
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

7 files changed, 36 insertions, 6 deletions

diff --git a/src/shadertools/qshaderbaker.cpp b/src/shadertools/qshaderbaker.cpp
index 11c3699..df30436 100644
--- a/src/shadertools/qshaderbaker.cpp
+++ b/src/shadertools/qshaderbaker.cpp
@@ -151,6 +151,7 @@ struct QShaderBakerPrivate
     QVector<QShaderBaker::GeneratedShader> reqVersions;
     QVector<QShader::Variant> variants;
     QByteArray preamble;
+    int batchLoc = 7;
     QSpirvCompiler compiler;
     QString errorMessage;
 };
@@ -313,6 +314,17 @@ void QShaderBaker::setPreamble(const QByteArray &preamble)
 }
 
 /*!
+    When generating a QShader::BatchableVertexShader variant, \a location
+    specifies the input location for the inserted vertex input. The value is by
+    default 7 and needs to be overridden only if the vertex shader already uses
+    input location 7.
+ */
+void QShaderBaker::setBatchableVertexShaderExtraInputLocation(int location)
+{
+    d->batchLoc = location;
+}
+
+/*!
     Runs the compilation and translation process.
 
     \return a QShader instance. To check if the process was successful,
@@ -347,6 +359,7 @@ QShader QShaderBaker::bake()
     QByteArray batchableSpirv;
     if (d->stage == QShader::VertexStage && d->variants.contains(QShader::BatchableVertexShader)) {
         d->compiler.setFlags(QSpirvCompiler::RewriteToMakeBatchableForSG);
+        d->compiler.setSGBatchingVertexInputLocation(d->batchLoc);
         batchableSpirv = d->compiler.compileToSpirv();
         if (batchableSpirv.isEmpty()) {
             d->errorMessage = d->compiler.errorMessage();
diff --git a/src/shadertools/qshaderbaker.h b/src/shadertools/qshaderbaker.h
index edac5fb..08a525c 100644
--- a/src/shadertools/qshaderbaker.h
+++ b/src/shadertools/qshaderbaker.h
@@ -65,6 +65,7 @@ public:
     void setGeneratedShaderVariants(const QVector<QShader::Variant> &v);
 
     void setPreamble(const QByteArray &preamble);
+    void setBatchableVertexShaderExtraInputLocation(int location);
 
     QShader bake();
 
diff --git a/src/shadertools/qshaderbatchablerewriter.cpp b/src/shadertools/qshaderbatchablerewriter.cpp
index 72b369f..260a1dc 100644
--- a/src/shadertools/qshaderbatchablerewriter.cpp
+++ b/src/shadertools/qshaderbatchablerewriter.cpp
@@ -41,7 +41,7 @@
 
 // This is a slightly modified version of qsgshaderrewriter.cpp from
 // qtdeclarative/src/quick/scenegraph/coreapi. Here we insert an extra vertex
-// attribute (_qt_order) at location 7.
+// input (_qt_order) at the specified input location.
 
 QT_BEGIN_NAMESPACE
 
@@ -164,7 +164,7 @@ Tokenizer::Token Tokenizer::next()
     return Token_EOF;
 }
 
-QByteArray addZAdjustment(const QByteArray &input)
+QByteArray addZAdjustment(const QByteArray &input, int vertexInputLocation)
 {
     Tokenizer tok;
     tok.initialize(input);
@@ -188,7 +188,9 @@ QByteArray addZAdjustment(const QByteArray &input)
     result.reserve(1024);
     result += QByteArray::fromRawData(input.constData(), voidPos - input.constData());
 
-    result += QByteArrayLiteral("layout(location = 7) in float _qt_order;\n");
+    result += QByteArrayLiteral("layout(location = ");
+    result += QByteArray::number(vertexInputLocation);
+    result += QByteArrayLiteral(") in float _qt_order;\n");
 
     // Find first brace '{'
     while (t != Tokenizer::Token_EOF && t != Tokenizer::Token_OpenBrace) t = tok.next();
diff --git a/src/shadertools/qshaderbatchablerewriter_p.h b/src/shadertools/qshaderbatchablerewriter_p.h
index 3ee8eca..b462cbb 100644
--- a/src/shadertools/qshaderbatchablerewriter_p.h
+++ b/src/shadertools/qshaderbatchablerewriter_p.h
@@ -56,7 +56,7 @@
 QT_BEGIN_NAMESPACE
 
 namespace QShaderBatchableRewriter {
-QByteArray addZAdjustment(const QByteArray &input);
+QByteArray addZAdjustment(const QByteArray &input, int vertexInputLocation);
 }
 
 QT_END_NAMESPACE
diff --git a/src/shadertools/qspirvcompiler.cpp b/src/shadertools/qspirvcompiler.cpp
index 0496c3a..e8f341e 100644
--- a/src/shadertools/qspirvcompiler.cpp
+++ b/src/shadertools/qspirvcompiler.cpp
@@ -163,6 +163,7 @@ struct QSpirvCompilerPrivate
     EShLanguage stage = EShLangVertex;
     QSpirvCompiler::Flags flags = 0;
     QByteArray preamble;
+    int batchAttrLoc = 7;
     QByteArray spirv;
     QString log;
 };
@@ -385,10 +386,15 @@ void QSpirvCompiler::setPreamble(const QByteArray &preamble)
     d->preamble = preamble;
 }
 
+void QSpirvCompiler::setSGBatchingVertexInputLocation(int location)
+{
+    d->batchAttrLoc = location;
+}
+
 QByteArray QSpirvCompiler::compileToSpirv()
 {
     if (d->stage == EShLangVertex && d->flags.testFlag(RewriteToMakeBatchableForSG) && d->batchableSource.isEmpty())
-        d->batchableSource = QShaderBatchableRewriter::addZAdjustment(d->source);
+        d->batchableSource = QShaderBatchableRewriter::addZAdjustment(d->source, d->batchAttrLoc);
 
     return d->compile() ? d->spirv : QByteArray();
 }
diff --git a/src/shadertools/qspirvcompiler_p.h b/src/shadertools/qspirvcompiler_p.h
index 4843f5d..63b5697 100644
--- a/src/shadertools/qspirvcompiler_p.h
+++ b/src/shadertools/qspirvcompiler_p.h
@@ -74,6 +74,7 @@ public:
     void setSourceString(const QByteArray &sourceString, QShader::Stage stage, const QString &fileName = QString());
     void setFlags(Flags flags);
     void setPreamble(const QByteArray &preamble);
+    void setSGBatchingVertexInputLocation(int location);
 
     QByteArray compileToSpirv();
     QString errorMessage() const;
diff --git a/tools/qsb/qsb.cpp b/tools/qsb/qsb.cpp
index 28660a4..1288c94 100644
--- a/tools/qsb/qsb.cpp
+++ b/tools/qsb/qsb.cpp
@@ -292,6 +292,10 @@ int main(int argc, char **argv)
     cmdLineParser.addPositionalArgument(QLatin1String("file"), QObject::tr("Vulkan GLSL source file to compile"), QObject::tr("file"));
     QCommandLineOption batchableOption({ "b", "batchable" }, QObject::tr("Also generates rewritten vertex shader for Qt Quick scene graph batching."));
     cmdLineParser.addOption(batchableOption);
+    QCommandLineOption batchLocOption("zorder-loc",
+                                      QObject::tr("The extra vertex input location when rewriting for batching. Defaults to 7."),
+                                      QObject::tr("location"));
+    cmdLineParser.addOption(batchLocOption);
     QCommandLineOption glslOption({ "g", "glsl" },
                                   QObject::tr("Comma separated list of GLSL versions to generate. (for example, \"100 es,120,330\")"),
                                   QObject::tr("versions"));
@@ -358,8 +362,11 @@ int main(int argc, char **argv)
 
         QVector<QShader::Variant> variants;
         variants << QShader::StandardShader;
-        if (cmdLineParser.isSet(batchableOption))
+        if (cmdLineParser.isSet(batchableOption)) {
             variants << QShader::BatchableVertexShader;
+            if (cmdLineParser.isSet(batchLocOption))
+                baker.setBatchableVertexShaderExtraInputLocation(cmdLineParser.value(batchLocOption).toInt());
+        }
 
         baker.setGeneratedShaderVariants(variants);