Fix planets-qml inner planets shading

* The shadow light was using the undefined matrix property which
  resulted in a matrix full of NaN's in the shader. This caused
  everything to be fully in shadows for the inner planets. Fixed
  to use the correct viewMatrix property.

* After fixing the above, it became clear that the inner planets
  were being shadowed with lots of artifacts. The only shadow
  casters are the planets Saturn and Uranus and their rings. In
  this configuration it makes no sense to try to shadow the other
  planets as this leads to bad shadow acne due to the huge
  distances involved vs the limited precision of the shadow
  depth texture. Fixed these artifacts by only applying shadows
  to Saturn and Uranus.

Task-number: QTBUG-53751
Change-Id: I96ab08117c9988c40f083a1345ec7f7d1b0f7ce6
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/examples/qt3d/planets-qml/shaders/gl3/planetDShadow.vert b/examples/qt3d/planets-qml/shaders/gl3/planetDShadow.vert
new file mode 100644
index 000000000..41a1db6e4
--- /dev/null
+++ b/examples/qt3d/planets-qml/shaders/gl3/planetDShadow.vert
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#version 150 core
+
+in vec3 vertexPosition;
+in vec3 vertexNormal;
+in vec2 vertexTexCoord;
+
+out vec4 positionInLightSpace;
+out vec3 position;
+out vec3 normal;
+out vec2 texCoord;
+
+uniform mat4 lightViewProjection;
+uniform mat4 modelMatrix;
+uniform mat4 modelView;
+uniform mat3 modelViewNormal;
+uniform mat4 mvp;
+
+uniform float texCoordScale;
+
+void main()
+{
+    const mat4 shadowMatrix = mat4(0.5, 0.0, 0.0, 0.0,
+                                   0.0, 0.5, 0.0, 0.0,
+                                   0.0, 0.0, 0.5, 0.0,
+                                   0.5, 0.5, 0.5, 1.0);
+
+    positionInLightSpace = shadowMatrix * lightViewProjection * modelMatrix * vec4(vertexPosition, 1.0);
+
+    texCoord = vertexTexCoord * texCoordScale;
+    normal = normalize(modelViewNormal * vertexNormal);
+    position = vec3(modelView * vec4(vertexPosition, 1.0));
+
+    gl_Position = mvp * vec4(vertexPosition, 1.0);
+}