Add the skeleton for a D3D12 backend

Proof of concept. The plan is to proceed slowly with supporting node types
one by one, starting with QSGRectangleNode.

Opaque rectangles work already, but only non-smooth for now. The renderer is
incomplete (no clip/opacity) and is based on simplerenderer on scenegraph playground.
Buffer handling is not necessarily optimal yet.

Use QT_QUICK_BACKEND=d3d12 to request this backend. Set QT_D3D_DEBUG=1 to
enable the D3D debug layer. The render loop handles everything, incl. swap
chain setup, handling resizes, etc. This being D3D, there are no further
enablers needed from the QtGui or platform plugin side.

By default the first hardware adapter is picked. In the absence of that,
WARP is tried. The list of adapters is printed at startup, use
QT_D3D_ADAPTER_INDEX to force a given card in case there are multiple
ones in the system.

The goal is not to productize a fast and great renderer, but to pave the way to
better future backends for D3D12 and similar graphics APIs.

Compiling in the support into Qt Quick is bad since the dependency onto
d3d12.dll is not necessarily acceptable, but it's good enough for now, this
being a wip branch.

Change-Id: Ifbe088e7507223328096b22eec2c73f77bb5680e
Reviewed-by: Andy Nichols <andy.nichols@theqtcompany.com>

3 files changed, 66 insertions, 25 deletions

diff --git a/src/quick/scenegraph/coreapi/qsggeometry.cpp b/src/quick/scenegraph/coreapi/qsggeometry.cpp
index 5012f6a31b..152bb253d7 100644
--- a/src/quick/scenegraph/coreapi/qsggeometry.cpp
+++ b/src/quick/scenegraph/coreapi/qsggeometry.cpp
@@ -53,10 +53,15 @@ QT_BEGIN_NAMESPACE
 
 QSGGeometry::Attribute QSGGeometry::Attribute::create(int attributeIndex, int tupleSize, int primitiveType, bool isPrimitive)
 {
-    Attribute a = { attributeIndex, tupleSize, primitiveType, isPrimitive, 0 };
+    Attribute a = { attributeIndex, tupleSize, primitiveType, isPrimitive, UNKNOWN, 0 };
     return a;
 }
 
+QSGGeometry::Attribute QSGGeometry::Attribute::createWithSemantic(int pos, int tupleSize, int type, Semantic semantic)
+{
+    Attribute a = { pos, tupleSize, type, semantic == POSITION, semantic, 0 };
+    return a;
+}
 
 /*!
     Convenience function which returns attributes to be used for 2D solid
@@ -66,7 +71,7 @@ QSGGeometry::Attribute QSGGeometry::Attribute::create(int attributeIndex, int tu
 const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_Point2D()
 {
     static Attribute data[] = {
-        QSGGeometry::Attribute::create(0, 2, GL_FLOAT, true)
+        Attribute::createWithSemantic(0, 2, GL_FLOAT, Attribute::POSITION)
     };
     static AttributeSet attrs = { 1, sizeof(float) * 2, data };
     return attrs;
@@ -79,8 +84,8 @@ const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_Point2D()
 const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_TexturedPoint2D()
 {
     static Attribute data[] = {
-        QSGGeometry::Attribute::create(0, 2, GL_FLOAT, true),
-        QSGGeometry::Attribute::create(1, 2, GL_FLOAT)
+        Attribute::createWithSemantic(0, 2, GL_FLOAT, Attribute::POSITION),
+        Attribute::createWithSemantic(1, 2, GL_FLOAT, Attribute::TEXCOORD)
     };
     static AttributeSet attrs = { 2, sizeof(float) * 4, data };
     return attrs;
@@ -93,8 +98,8 @@ const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_TexturedPoint2D(
 const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_ColoredPoint2D()
 {
     static Attribute data[] = {
-        QSGGeometry::Attribute::create(0, 2, GL_FLOAT, true),
-        QSGGeometry::Attribute::create(1, 4, GL_UNSIGNED_BYTE)
+        Attribute::createWithSemantic(0, 2, GL_FLOAT, Attribute::POSITION),
+        Attribute::createWithSemantic(1, 4, GL_UNSIGNED_BYTE, Attribute::COLOR)
     };
     static AttributeSet attrs = { 2, 2 * sizeof(float) + 4 * sizeof(char), data };
     return attrs;
diff --git a/src/quick/scenegraph/coreapi/qsggeometry.h b/src/quick/scenegraph/coreapi/qsggeometry.h
index 5773b6abd1..6b1e3e3f4e 100644
--- a/src/quick/scenegraph/coreapi/qsggeometry.h
+++ b/src/quick/scenegraph/coreapi/qsggeometry.h
@@ -54,15 +54,25 @@ public:
 
     struct Q_QUICK_EXPORT Attribute
     {
+        enum Semantic {
+            UNKNOWN,
+            POSITION,
+            COLOR,
+            TEXCOORD
+        };
+
         int position;
         int tupleSize;
         int type;
 
         uint isVertexCoordinate : 1;
 
-        uint reserved : 31;
+        Semantic semantic : 4;
+
+        uint reserved : 27;
 
         static Attribute create(int pos, int tupleSize, int primitiveType, bool isPosition = false);
+        static Attribute createWithSemantic(int pos, int tupleSize, int type, Semantic semantic);
     };
 
     struct AttributeSet {
@@ -104,12 +114,35 @@ public:
         StaticPattern       = 3
     };
 
+    // Equivalents to GL_* drawing modes.
+    enum DrawingMode {
+        DrawPoints = 0x0000,
+        DrawLines = 0x0001,
+        DrawLineLoop = 0x0002,
+        DrawLineStrip = 0x0003,
+        DrawTriangles = 0x0004,
+        DrawTriangleStrip = 0x0005,
+        DrawTriangleFan = 0x0006
+    };
+
+    // Equivalents to GL_BYTE and similar type constants.
+    enum Type {
+        TypeByte = 0x1400,
+        TypeUnsignedByte = 0x1401,
+        TypeShort = 0x1402,
+        TypeUnsignedShort = 0x1403,
+        TypeInt = 0x1404,
+        TypeUnsignedInt = 0x1405,
+        TypeFloat = 0x1406
+    };
+
     QSGGeometry(const QSGGeometry::AttributeSet &attribs,
                 int vertexCount,
                 int indexCount = 0,
-                int indexType = GL_UNSIGNED_SHORT);
+                int indexType = TypeUnsignedShort);
     virtual ~QSGGeometry();
 
+    // ### Qt 6: GL types to be removed from the public API
     void setDrawingMode(GLenum mode);
     inline GLenum drawingMode() const { return m_drawing_mode; }
 
@@ -187,25 +220,25 @@ private:
 
 inline uint *QSGGeometry::indexDataAsUInt()
 {
-    Q_ASSERT(m_index_type == GL_UNSIGNED_INT);
+    Q_ASSERT(m_index_type == TypeUnsignedInt);
     return static_cast<uint *>(indexData());
 }
 
 inline quint16 *QSGGeometry::indexDataAsUShort()
 {
-    Q_ASSERT(m_index_type == GL_UNSIGNED_SHORT);
+    Q_ASSERT(m_index_type == TypeUnsignedShort);
     return static_cast<quint16 *>(indexData());
 }
 
 inline const uint *QSGGeometry::indexDataAsUInt() const
 {
-    Q_ASSERT(m_index_type == GL_UNSIGNED_INT);
+    Q_ASSERT(m_index_type == TypeUnsignedInt);
     return static_cast<const uint *>(indexData());
 }
 
 inline const quint16 *QSGGeometry::indexDataAsUShort() const
 {
-    Q_ASSERT(m_index_type == GL_UNSIGNED_SHORT);
+    Q_ASSERT(m_index_type == TypeUnsignedShort);
     return static_cast<const quint16 *>(indexData());
 }
 
@@ -214,7 +247,7 @@ inline QSGGeometry::Point2D *QSGGeometry::vertexDataAsPoint2D()
     Q_ASSERT(m_attributes.count == 1);
     Q_ASSERT(m_attributes.stride == 2 * sizeof(float));
     Q_ASSERT(m_attributes.attributes[0].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[0].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[0].type == TypeFloat);
     Q_ASSERT(m_attributes.attributes[0].position == 0);
     return static_cast<Point2D *>(m_data);
 }
@@ -225,10 +258,10 @@ inline QSGGeometry::TexturedPoint2D *QSGGeometry::vertexDataAsTexturedPoint2D()
     Q_ASSERT(m_attributes.stride == 4 * sizeof(float));
     Q_ASSERT(m_attributes.attributes[0].position == 0);
     Q_ASSERT(m_attributes.attributes[0].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[0].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[0].type == TypeFloat);
     Q_ASSERT(m_attributes.attributes[1].position == 1);
     Q_ASSERT(m_attributes.attributes[1].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[1].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[1].type == TypeFloat);
     return static_cast<TexturedPoint2D *>(m_data);
 }
 
@@ -238,10 +271,10 @@ inline QSGGeometry::ColoredPoint2D *QSGGeometry::vertexDataAsColoredPoint2D()
     Q_ASSERT(m_attributes.stride == 2 * sizeof(float) + 4 * sizeof(char));
     Q_ASSERT(m_attributes.attributes[0].position == 0);
     Q_ASSERT(m_attributes.attributes[0].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[0].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[0].type == TypeFloat);
     Q_ASSERT(m_attributes.attributes[1].position == 1);
     Q_ASSERT(m_attributes.attributes[1].tupleSize == 4);
-    Q_ASSERT(m_attributes.attributes[1].type == GL_UNSIGNED_BYTE);
+    Q_ASSERT(m_attributes.attributes[1].type == TypeUnsignedByte);
     return static_cast<ColoredPoint2D *>(m_data);
 }
 
@@ -250,7 +283,7 @@ inline const QSGGeometry::Point2D *QSGGeometry::vertexDataAsPoint2D() const
     Q_ASSERT(m_attributes.count == 1);
     Q_ASSERT(m_attributes.stride == 2 * sizeof(float));
     Q_ASSERT(m_attributes.attributes[0].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[0].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[0].type == TypeFloat);
     Q_ASSERT(m_attributes.attributes[0].position == 0);
     return static_cast<const Point2D *>(m_data);
 }
@@ -261,10 +294,10 @@ inline const QSGGeometry::TexturedPoint2D *QSGGeometry::vertexDataAsTexturedPoin
     Q_ASSERT(m_attributes.stride == 4 * sizeof(float));
     Q_ASSERT(m_attributes.attributes[0].position == 0);
     Q_ASSERT(m_attributes.attributes[0].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[0].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[0].type == TypeFloat);
     Q_ASSERT(m_attributes.attributes[1].position == 1);
     Q_ASSERT(m_attributes.attributes[1].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[1].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[1].type == TypeFloat);
     return static_cast<const TexturedPoint2D *>(m_data);
 }
 
@@ -274,18 +307,18 @@ inline const QSGGeometry::ColoredPoint2D *QSGGeometry::vertexDataAsColoredPoint2
     Q_ASSERT(m_attributes.stride == 2 * sizeof(float) + 4 * sizeof(char));
     Q_ASSERT(m_attributes.attributes[0].position == 0);
     Q_ASSERT(m_attributes.attributes[0].tupleSize == 2);
-    Q_ASSERT(m_attributes.attributes[0].type == GL_FLOAT);
+    Q_ASSERT(m_attributes.attributes[0].type == TypeFloat);
     Q_ASSERT(m_attributes.attributes[1].position == 1);
     Q_ASSERT(m_attributes.attributes[1].tupleSize == 4);
-    Q_ASSERT(m_attributes.attributes[1].type == GL_UNSIGNED_BYTE);
+    Q_ASSERT(m_attributes.attributes[1].type == TypeUnsignedByte);
     return static_cast<const ColoredPoint2D *>(m_data);
 }
 
 int QSGGeometry::sizeOfIndex() const
 {
-    if (m_index_type == GL_UNSIGNED_SHORT) return 2;
-    else if (m_index_type == GL_UNSIGNED_BYTE) return 1;
-    else if (m_index_type == GL_UNSIGNED_INT) return 4;
+    if (m_index_type == TypeUnsignedShort) return 2;
+    else if (m_index_type == TypeUnsignedByte) return 1;
+    else if (m_index_type == TypeUnsignedInt) return 4;
     return 0;
 }
 
diff --git a/src/quick/scenegraph/coreapi/qsgnode.h b/src/quick/scenegraph/coreapi/qsgnode.h
index d294e6f3ca..144f42da1c 100644
--- a/src/quick/scenegraph/coreapi/qsgnode.h
+++ b/src/quick/scenegraph/coreapi/qsgnode.h
@@ -204,6 +204,9 @@ public:
     const QMatrix4x4 *matrix() const { return m_matrix; }
     const QSGClipNode *clipList() const { return m_clip_list; }
 
+    void setMatrix(const QMatrix4x4 *matrix) { m_matrix = matrix; }
+    void setClipList(const QSGClipNode *clipList) { m_clip_list = clipList; }
+
 protected:
     QSGBasicGeometryNode(NodeType type);
     QSGBasicGeometryNode(QSGBasicGeometryNodePrivate &dd, NodeType type);