clip-planes-qml examples

Demonstrates use of:
-StencilOp / StencilTest
-StateSet and nested StateSet
-ClipPlane
-Multiple render passes with different shaders
-Use of layers

Change-Id: I2d3f87e99e1fdbf9ed22e81838d6cc1744b6b8c1
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 131 insertions, 0 deletions

diff --git a/examples/qt3d/clip-planes-qml/ClipCappingFrameGraph.qml b/examples/qt3d/clip-planes-qml/ClipCappingFrameGraph.qml
new file mode 100644
index 000000000..2716fa25b
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+++ b/examples/qt3d/clip-planes-qml/ClipCappingFrameGraph.qml
@@ -0,0 +1,131 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Paul Lemire
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import Qt3D 2.0
+import Qt3D.Renderer 2.0
+
+Viewport {
+    property alias camera: cameraSelector.camera
+
+    CameraSelector {
+        id: cameraSelector
+
+        StateSet {
+            // Enable 3 clipping planes
+            renderStates: [
+                ClipPlane { plane: 0 },
+                ClipPlane { plane: 1 },
+                ClipPlane { plane: 2 },
+                DepthTest { func: DepthTest.LessOrEqual }
+            ]
+
+            // Branch 1
+            LayerFilter {
+                // Render entities with their regular material
+                // Fills depth buffer for entities that are clipped
+                layers: ["content", "visualization"]
+                ClearBuffer {
+                    buffers: ClearBuffer.ColorDepthBuffer
+                    RenderPassFilter {
+                        includes: Annotation { name: "pass"; value: "material" }
+                    }
+                }
+            }
+
+            // Branch 2
+            ClearBuffer {
+                // Enable and fill Stencil to later generate caps
+                buffers: ClearBuffer.StencilBuffer
+                StateSet {
+                    // Disable depth culling
+                    // Incr for back faces
+                    // Decr for front faces
+                    // No need to output color values
+                    renderStates: [
+                        StencilTest {
+                            front {
+                                func: StencilTestSeparate.Always
+                                ref: 0; mask: 0
+                            }
+                            back {
+                                func: StencilTestSeparate.Always
+                                ref: 0; mask: 0
+                            }
+                        },
+                        StencilOp {
+                            front.stencilDepthPass: StencilOpSeparate.Decr
+                            back.stencilDepthPass: StencilOpSeparate.Incr
+                        },
+                        ColorMask { red: false; green: false; blue: false; alpha: false }
+                    ]
+
+                    LayerFilter {
+                        layers: "content"
+                        RenderPassFilter {
+                            includes: Annotation { name: "pass"; value: "stencilFill"; }
+                        }
+                    }
+                }
+            }
+        }
+
+        // Branch 3
+        StateSet {
+            // Draw caps using stencil buffer
+            LayerFilter {
+                layers: "caps"
+                RenderPassFilter {
+                    includes: Annotation { name: "pass"; value: "capping"; }
+                }
+            }
+
+            // Draw back faces - front faces -> caps
+            renderStates: [
+                StencilTest {
+                    front {
+                        func: StencilTestSeparate.NotEqual
+                        ref: 0; mask: ~0
+                    }
+                    back {
+                        func: StencilTestSeparate.NotEqual
+                        ref: 0; mask: ~0
+                    }
+                }
+            ]
+        }
+    }
+}
+