QShaderGenerator: fix substitution for attributes on GL2/ES2

GL2/ES2 expect it to be attribute and not in like later versions of OpenGL.

Task-number: QTBUG-74829
Change-Id: Iddd22386ed315d6e6843d8225e49a4b73b6ad9ba
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

4 files changed, 44 insertions, 2 deletions

diff --git a/src/gui/util/qshaderformat.cpp b/src/gui/util/qshaderformat.cpp
index 373bfb9e7e..e4e3718199 100644
--- a/src/gui/util/qshaderformat.cpp
+++ b/src/gui/util/qshaderformat.cpp
@@ -43,6 +43,7 @@ QT_BEGIN_NAMESPACE
 
 QShaderFormat::QShaderFormat() Q_DECL_NOTHROW
     : m_api(NoApi)
+    , m_shaderType(Fragment)
 {
 }
 
@@ -106,6 +107,9 @@ bool QShaderFormat::supports(const QShaderFormat &other) const Q_DECL_NOTHROW
     if (m_version < other.m_version)
         return false;
 
+    if (m_shaderType != other.m_shaderType)
+        return false;
+
     const auto containsAllExtensionsFromOther = std::includes(m_extensions.constBegin(),
                                                               m_extensions.constEnd(),
                                                               other.m_extensions.constBegin(),
@@ -119,12 +123,23 @@ bool QShaderFormat::supports(const QShaderFormat &other) const Q_DECL_NOTHROW
     return true;
 }
 
+QShaderFormat::ShaderType QShaderFormat::shaderType() const Q_DECL_NOTHROW
+{
+    return m_shaderType;
+}
+
+void QShaderFormat::setShaderType(QShaderFormat::ShaderType shaderType) Q_DECL_NOTHROW
+{
+    m_shaderType = shaderType;
+}
+
 bool operator==(const QShaderFormat &lhs, const QShaderFormat &rhs) Q_DECL_NOTHROW
 {
     return lhs.api() == rhs.api()
         && lhs.version() == rhs.version()
         && lhs.extensions() == rhs.extensions()
-        && lhs.vendor() == rhs.vendor();
+        && lhs.vendor() == rhs.vendor()
+        && lhs.shaderType() == rhs.shaderType();
 }
 
 QT_END_NAMESPACE
diff --git a/src/gui/util/qshaderformat_p.h b/src/gui/util/qshaderformat_p.h
index 064c2364a7..8d5e83bd22 100644
--- a/src/gui/util/qshaderformat_p.h
+++ b/src/gui/util/qshaderformat_p.h
@@ -69,6 +69,15 @@ public:
         OpenGLES
     };
 
+    enum ShaderType : int {
+        Vertex = 0,
+        TessellationControl,
+        TessellationEvaluation,
+        Geometry,
+        Fragment,
+        Compute
+    };
+
     Q_GUI_EXPORT QShaderFormat() Q_DECL_NOTHROW;
 
     Q_GUI_EXPORT Api api() const Q_DECL_NOTHROW;
@@ -86,11 +95,15 @@ public:
     Q_GUI_EXPORT bool isValid() const Q_DECL_NOTHROW;
     Q_GUI_EXPORT bool supports(const QShaderFormat &other) const Q_DECL_NOTHROW;
 
+    Q_GUI_EXPORT ShaderType shaderType() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT void setShaderType(ShaderType shaderType) Q_DECL_NOTHROW;
+
 private:
     Api m_api;
     QVersionNumber m_version;
     QStringList m_extensions;
     QString m_vendor;
+    ShaderType m_shaderType;
 };
 
 Q_GUI_EXPORT bool operator==(const QShaderFormat &lhs, const QShaderFormat &rhs) Q_DECL_NOTHROW;
diff --git a/src/gui/util/qshadergenerator.cpp b/src/gui/util/qshadergenerator.cpp
index 60cf5a2fc5..9d2cc387e0 100644
--- a/src/gui/util/qshadergenerator.cpp
+++ b/src/gui/util/qshadergenerator.cpp
@@ -56,7 +56,10 @@ namespace
             case QShaderLanguage::Const:
                 return "const";
             case QShaderLanguage::Input:
-                return "varying";
+                if (format.shaderType() == QShaderFormat::Vertex)
+                    return "attribute";
+                else
+                    return "varying";
             case QShaderLanguage::Output:
                 return ""; // Although fragment shaders for <=2 only have fixed outputs
             case QShaderLanguage::Uniform:
diff --git a/src/gui/util/qshadernodesloader.cpp b/src/gui/util/qshadernodesloader.cpp
index 9badbb94df..5369e8bd4c 100644
--- a/src/gui/util/qshadernodesloader.cpp
+++ b/src/gui/util/qshadernodesloader.cpp
@@ -251,6 +251,17 @@ void QShaderNodesLoader::load(const QJsonObject &prototypesObject)
                     break;
                 }
 
+                // We default out to a Fragment ShaderType if nothing is specified
+                // as that was the initial behavior we introduced
+                const QString shaderType = formatObject.value(QStringLiteral("shaderType")).toString();
+                format.setShaderType(shaderType == QStringLiteral("Fragment") ? QShaderFormat::Fragment
+                                   : shaderType == QStringLiteral("Vertex") ? QShaderFormat::Vertex
+                                   : shaderType == QStringLiteral("TessellationControl") ? QShaderFormat::TessellationControl
+                                   : shaderType == QStringLiteral("TessellationEvaluation") ? QShaderFormat::TessellationEvaluation
+                                   : shaderType == QStringLiteral("Geometry") ? QShaderFormat::Geometry
+                                   : shaderType == QStringLiteral("Compute") ? QShaderFormat::Compute
+                                   : QShaderFormat::Fragment);
+
                 const QByteArray substitution = substitutionValue.toString().toUtf8();
 
                 const QJsonValue snippetsValue = ruleObject.value(QStringLiteral("headerSnippets"));