Set the viewProjection and its inverse as uniforms if used

These are useful for performing ray marching in the fragment shader and
for mapping from screenspace or NDC to world space in general.

Change-Id: I1f273f16c85cdf6c46c03a63f80a6202305c7eaa
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

2 files changed, 17 insertions, 0 deletions

diff --git a/src/render/backend/renderview.cpp b/src/render/backend/renderview.cpp
index 8d40f2882..0c45366c4 100644
--- a/src/render/backend/renderview.cpp
+++ b/src/render/backend/renderview.cpp
@@ -114,12 +114,14 @@ RenderView::StandardUniformsPFuncsHash RenderView::initializeStandardUniformSett
     setters.insert(StringToInt::lookupId(QLatin1String("viewMatrix")), &RenderView::viewMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("projectionMatrix")), &RenderView::projectionMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("modelView")), &RenderView::modelViewMatrix);
+    setters.insert(StringToInt::lookupId(QLatin1String("viewProjectionMatrix")), &RenderView::viewProjectionMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("modelViewProjection")), &RenderView::modelViewProjectionMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("mvp")), &RenderView::modelViewProjectionMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("inverseModelMatrix")), &RenderView::inverseModelMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("inverseViewMatrix")), &RenderView::inverseViewMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("inverseProjectionMatrix")), &RenderView::inverseProjectionMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("inverseModelView")), &RenderView::inverseModelViewMatrix);
+    setters.insert(StringToInt::lookupId(QLatin1String("inverseViewProjectionMatrix")), &RenderView::inverseViewProjectionMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("inverseModelViewProjection")), &RenderView::inverseModelViewProjectionMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("modelNormalMatrix")), &RenderView::modelNormalMatrix);
     setters.insert(StringToInt::lookupId(QLatin1String("modelViewNormal")), &RenderView::modelViewNormalMatrix);
@@ -151,6 +153,12 @@ QUniformValue RenderView::modelViewMatrix(const QMatrix4x4 &model) const
     return QUniformValue(QVariant::fromValue(m_data.m_viewMatrix * model));
 }
 
+QUniformValue RenderView::viewProjectionMatrix(const QMatrix4x4 &model) const
+{
+    Q_UNUSED(model);
+    return QUniformValue(QVariant::fromValue(m_data.m_renderCameraLens->projection() * m_data.m_viewMatrix));
+}
+
 QUniformValue RenderView::modelViewProjectionMatrix(const QMatrix4x4 &model) const
 {
     return QUniformValue(QVariant::fromValue(m_data.m_viewProjectionMatrix * model));
@@ -179,6 +187,13 @@ QUniformValue RenderView::inverseModelViewMatrix(const QMatrix4x4 &model) const
     return QUniformValue(QVariant::fromValue((m_data.m_viewMatrix * model).inverted()));
 }
 
+QUniformValue RenderView::inverseViewProjectionMatrix(const QMatrix4x4 &model) const
+{
+    Q_UNUSED(model);
+    const auto viewProjectionMatrix = m_data.m_renderCameraLens->projection() * m_data.m_viewMatrix;
+    return QUniformValue(QVariant::fromValue(viewProjectionMatrix.inverted()));
+}
+
 QUniformValue RenderView::inverseModelViewProjectionMatrix(const QMatrix4x4 &model) const
 {
     return QUniformValue(QVariant::fromValue((m_data.m_viewProjectionMatrix * model).inverted(0)));
diff --git a/src/render/backend/renderview_p.h b/src/render/backend/renderview_p.h
index 0b01744e9..1e943a80b 100644
--- a/src/render/backend/renderview_p.h
+++ b/src/render/backend/renderview_p.h
@@ -282,11 +282,13 @@ private:
     QUniformValue viewMatrix(const QMatrix4x4&) const;
     QUniformValue projectionMatrix(const QMatrix4x4 &) const;
     QUniformValue modelViewMatrix(const QMatrix4x4 &model) const;
+    QUniformValue viewProjectionMatrix(const QMatrix4x4 &model) const;
     QUniformValue modelViewProjectionMatrix(const QMatrix4x4 &model) const;
     QUniformValue inverseModelMatrix(const QMatrix4x4 &model) const;
     QUniformValue inverseViewMatrix(const QMatrix4x4 &) const;
     QUniformValue inverseProjectionMatrix(const QMatrix4x4 &) const;
     QUniformValue inverseModelViewMatrix(const QMatrix4x4 &model) const;
+    QUniformValue inverseViewProjectionMatrix(const QMatrix4x4 &model) const;
     QUniformValue inverseModelViewProjectionMatrix(const QMatrix4x4 &model) const;
     QUniformValue modelNormalMatrix(const QMatrix4x4 &model) const;
     QUniformValue modelViewNormalMatrix(const QMatrix4x4 &model) const;