QShaderGenerator: add a #define LAYER_name for each layer

This will make it more convenient to insert conditional code
based on whether a layer is defined or not.

Change-Id: Ia72b569f022dd2ee723bf2493710eab709042639
Reviewed-by: Mike Krus <mike.krus@kdab.com>
(cherry picked from commit 7889cf1c6f9790391690ce31f391529b2dd8230e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 48 insertions, 0 deletions

diff --git a/src/render/shadergraph/qshadergenerator.cpp b/src/render/shadergraph/qshadergenerator.cpp
index f80502fcc..a33110719 100644
--- a/src/render/shadergraph/qshadergenerator.cpp
+++ b/src/render/shadergraph/qshadergenerator.cpp
@@ -507,6 +507,17 @@ namespace
         }
         }
     }
+
+    QByteArrayList layerDefines(const QStringList &enabledLayers) noexcept
+    {
+        QByteArrayList defines;
+        const QString defineTemplate = QStringLiteral("#define LAYER_%1");
+
+        for (const QString &layer : enabledLayers)
+            defines << defineTemplate.arg(layer).toUtf8();
+
+        return defines;
+    }
 }
 
 QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers) const
@@ -518,6 +529,7 @@ QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers)
 
     code << versionString(format);
     code << QByteArray();
+    code << layerDefines(enabledLayers);
 
     if (format.api() == QShaderFormat::VulkanFlavoredGLSL || format.api() == QShaderFormat::RHI) {
         GLSL45HeaderWriter builder;
diff --git a/tests/auto/render/shadergraph/qshadergenerator/tst_qshadergenerator.cpp b/tests/auto/render/shadergraph/qshadergenerator/tst_qshadergenerator.cpp
index e386ae09f..98f571328 100644
--- a/tests/auto/render/shadergraph/qshadergenerator/tst_qshadergenerator.cpp
+++ b/tests/auto/render/shadergraph/qshadergenerator/tst_qshadergenerator.cpp
@@ -202,6 +202,7 @@ private slots:
     void shouldHandlePortNamesPrefixingOneAnother();
     void shouldHandleNodesWithMultipleOutputPorts();
     void shouldHandleExpressionsInInputNodes();
+    void shouldGenerateLayerDefines();
 };
 
 void tst_QShaderGenerator::shouldHaveDefaultState()
@@ -860,6 +861,8 @@ void tst_QShaderGenerator::shouldGenerateDifferentCodeDependingOnActiveLayers()
         const auto expected = QByteArrayList()
                 << "#version 400 core"
                 << ""
+                << "#define LAYER_diffuseUniform"
+                << "#define LAYER_normalUniform"
                 << "uniform vec3 normalUniform;"
                 << "uniform vec4 diffuseUniform;"
                 << "#pragma include gl4/lightmodel.frag.inc"
@@ -880,6 +883,8 @@ void tst_QShaderGenerator::shouldGenerateDifferentCodeDependingOnActiveLayers()
         // THEN
         const auto expected = QByteArrayList() << "#version 400 core"
                                                << ""
+                                               << "#define LAYER_diffuseUniform"
+                                               << "#define LAYER_normalTexture"
                                                << "in vec2 texCoord;"
                                                << "uniform sampler2D normalTexture;"
                                                << "uniform vec4 diffuseUniform;"
@@ -903,6 +908,8 @@ void tst_QShaderGenerator::shouldGenerateDifferentCodeDependingOnActiveLayers()
         const auto expected = QByteArrayList()
                 << "#version 400 core"
                 << ""
+                << "#define LAYER_diffuseTexture"
+                << "#define LAYER_normalUniform"
                 << "in vec2 texCoord;"
                 << "uniform vec3 normalUniform;"
                 << "uniform sampler2D diffuseTexture;"
@@ -926,6 +933,8 @@ void tst_QShaderGenerator::shouldGenerateDifferentCodeDependingOnActiveLayers()
         const auto expected = QByteArrayList()
                 << "#version 400 core"
                 << ""
+                << "#define LAYER_diffuseTexture"
+                << "#define LAYER_normalTexture"
                 << "in vec2 texCoord;"
                 << "uniform sampler2D normalTexture;"
                 << "uniform sampler2D diffuseTexture;"
@@ -1050,6 +1059,8 @@ void tst_QShaderGenerator::shouldUseGlobalVariableRatherThanTemporaries()
         const auto expected = QByteArrayList()
                 << "#version 400 core"
                 << ""
+                << "#define LAYER_diffuseUniform"
+                << "#define LAYER_normalUniform"
                 << "in vec4 vertexPosition;"
                 << "out vec4 fragColor;"
                 << ""
@@ -1422,6 +1433,31 @@ void tst_QShaderGenerator::shouldHandleExpressionsInInputNodes()
     QCOMPARE(code, expected.join("\n"));
 }
 
+void tst_QShaderGenerator::shouldGenerateLayerDefines()
+{
+    // GIVEN
+    const auto gl4 = createFormat(QShaderFormat::OpenGLCoreProfile, 4, 0);
+
+    auto generator = QShaderGenerator();
+    generator.format = gl4;
+
+    // WHEN
+    const auto code = generator.createShaderCode({"layer1", "layer2"});
+
+    // THEN
+    const auto expected = QByteArrayList()
+            << "#version 400 core"
+            << ""
+            << "#define LAYER_layer1"
+            << "#define LAYER_layer2"
+            << ""
+            << "void main()"
+            << "{"
+            << "}"
+            << "";
+    QCOMPARE(code, expected.join("\n"));
+}
+
 QTEST_MAIN(tst_QShaderGenerator)
 
 #include "tst_qshadergenerator.moc"