Properly handle alpha to coverage state in non-cloning codepath

Also improve the alpha to coverage handlign in the helpers by using
a single function rather than two.

This removes GL errors about bad glFace enum values (caused by bad
handlign of alpha to coverage in switch statement, which led to a
FrontFace state being created with bad data).

Change-Id: I832d92fcb07134525f421d3a3b4d12e9f5f6428c
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

16 files changed, 39 insertions, 61 deletions

diff --git a/src/render/graphicshelpers/graphicscontext.cpp b/src/render/graphicshelpers/graphicscontext.cpp
index 3d387be66..1600f24e6 100644
--- a/src/render/graphicshelpers/graphicscontext.cpp
+++ b/src/render/graphicshelpers/graphicscontext.cpp
@@ -832,14 +832,9 @@ void GraphicsContext::buildUniformBuffer(const QVariant &v, const ShaderUniform
     m_glHelper->buildUniformBuffer(v, description, buffer);
 }
 
-void GraphicsContext::enableAlphaCoverage()
+void GraphicsContext::setAlphaCoverageEnabled(bool enabled)
 {
-    m_glHelper->enableAlphaCoverage();
-}
-
-void GraphicsContext::disableAlphaCoverage()
-{
-    m_glHelper->disableAlphaCoverage();
+    m_glHelper->setAlphaCoverageEnabled(enabled);
 }
 
 GLuint GraphicsContext::boundFrameBufferObject()
diff --git a/src/render/graphicshelpers/graphicscontext_p.h b/src/render/graphicshelpers/graphicscontext_p.h
index ea6db02ed..d00292cb4 100644
--- a/src/render/graphicshelpers/graphicscontext_p.h
+++ b/src/render/graphicshelpers/graphicscontext_p.h
@@ -192,7 +192,6 @@ public:
     void    cullFace(GLenum mode);
     void    depthMask(GLenum mode);
     void    depthTest(GLenum mode);
-    void    disableAlphaCoverage();
     void    disableClipPlane(int clipPlane);
     void    disablei(GLenum cap, GLuint index);
     void    disablePrimitiveRestart();
@@ -201,13 +200,13 @@ public:
     void    drawArraysInstanced(GLenum primitiveType, GLint first, GLsizei count, GLsizei instances);
     void    drawElements(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void * indices, GLint baseVertex = 0);
     void    drawElementsInstanced(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void * indices, GLsizei instances, GLint baseVertex = 0, GLint baseInstance = 0);
-    void    enableAlphaCoverage();
     void    enableClipPlane(int clipPlane);
     void    enablei(GLenum cap, GLuint index);
     void    enablePrimitiveRestart(int restartIndex);
     void    frontFace(GLenum mode);
     GLint   maxClipPlaneCount();
     void    pointSize(bool programmable, GLfloat value);
+    void    setAlphaCoverageEnabled(bool enabled);
     void    setClipPlane(int clipPlane, const QVector3D &normal, float distance);
     void    setSeamlessCubemap(bool enable);
     void    setVerticesPerPatch(GLint verticesPerPatch);
diff --git a/src/render/graphicshelpers/graphicshelperes2.cpp b/src/render/graphicshelpers/graphicshelperes2.cpp
index 32bc703f1..cc8de52ed 100644
--- a/src/render/graphicshelpers/graphicshelperes2.cpp
+++ b/src/render/graphicshelpers/graphicshelperes2.cpp
@@ -277,14 +277,10 @@ void GraphicsHelperES2::frontFace(GLenum mode)
     m_funcs->glFrontFace(mode);
 }
 
-void GraphicsHelperES2::enableAlphaCoverage()
+void GraphicsHelperES2::setAlphaCoverageEnabled(bool enabled)
 {
-    m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
-}
-
-void GraphicsHelperES2::disableAlphaCoverage()
-{
-    m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+    enabled ? m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE)
+            : m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
 }
 
 GLuint GraphicsHelperES2::createFrameBufferObject()
diff --git a/src/render/graphicshelpers/graphicshelperes2_p.h b/src/render/graphicshelpers/graphicshelperes2_p.h
index 1ef56d1f2..f5273a25a 100644
--- a/src/render/graphicshelpers/graphicshelperes2_p.h
+++ b/src/render/graphicshelpers/graphicshelperes2_p.h
@@ -85,7 +85,6 @@ public:
     void cullFace(GLenum mode) Q_DECL_OVERRIDE;
     void depthMask(GLenum mode) Q_DECL_OVERRIDE;
     void depthTest(GLenum mode) Q_DECL_OVERRIDE;
-    void disableAlphaCoverage() Q_DECL_OVERRIDE;
     void disableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void disablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void disablePrimitiveRestart() Q_DECL_OVERRIDE;
@@ -95,7 +94,6 @@ public:
     void drawBuffers(GLsizei n, const int *bufs) Q_DECL_OVERRIDE;
     void drawElements(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLint baseVertex = 0) Q_DECL_OVERRIDE;
     void drawElementsInstanced(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLsizei instances, GLint baseVertex = 0,  GLint baseInstance = 0) Q_DECL_OVERRIDE;
-    void enableAlphaCoverage() Q_DECL_OVERRIDE;
     void enableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void enablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void enablePrimitiveRestart(int primitiveRestartIndex) Q_DECL_OVERRIDE;
@@ -110,6 +108,7 @@ public:
     QVector<ShaderUniform> programUniformsAndLocations(GLuint programId) Q_DECL_OVERRIDE;
     QVector<ShaderStorageBlock> programShaderStorageBlocks(GLuint programId) Q_DECL_OVERRIDE;
     void releaseFrameBufferObject(GLuint frameBufferId) Q_DECL_OVERRIDE;
+    void setAlphaCoverageEnabled(bool enable) Q_DECL_OVERRIDE;
     void setClipPlane(int clipPlane, const QVector3D &normal, float distance) Q_DECL_OVERRIDE;
     void setSeamlessCubemap(bool enable) Q_DECL_OVERRIDE;
     void setVerticesPerPatch(GLint verticesPerPatch) Q_DECL_OVERRIDE;
diff --git a/src/render/graphicshelpers/graphicshelpergl2.cpp b/src/render/graphicshelpers/graphicshelpergl2.cpp
index 2c0bd1ec9..2a77982d9 100644
--- a/src/render/graphicshelpers/graphicshelpergl2.cpp
+++ b/src/render/graphicshelpers/graphicshelpergl2.cpp
@@ -260,14 +260,10 @@ void GraphicsHelperGL2::frontFace(GLenum mode)
     m_funcs->glFrontFace(mode);
 }
 
-void GraphicsHelperGL2::enableAlphaCoverage()
+void GraphicsHelperGL2::setAlphaCoverageEnabled(bool enabled)
 {
-    m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
-}
-
-void GraphicsHelperGL2::disableAlphaCoverage()
-{
-    m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+    enabled ? m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE)
+            : m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
 }
 
 GLuint GraphicsHelperGL2::createFrameBufferObject()
diff --git a/src/render/graphicshelpers/graphicshelpergl2_p.h b/src/render/graphicshelpers/graphicshelpergl2_p.h
index e5e92c96c..a928f3be7 100644
--- a/src/render/graphicshelpers/graphicshelpergl2_p.h
+++ b/src/render/graphicshelpers/graphicshelpergl2_p.h
@@ -87,7 +87,6 @@ public:
     void cullFace(GLenum mode) Q_DECL_OVERRIDE;
     void depthMask(GLenum mode) Q_DECL_OVERRIDE;
     void depthTest(GLenum mode) Q_DECL_OVERRIDE;
-    void disableAlphaCoverage() Q_DECL_OVERRIDE;
     void disableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void disablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void disablePrimitiveRestart() Q_DECL_OVERRIDE;
@@ -97,7 +96,6 @@ public:
     void drawBuffers(GLsizei n, const int *bufs) Q_DECL_OVERRIDE;
     void drawElements(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLint baseVertex = 0) Q_DECL_OVERRIDE;
     void drawElementsInstanced(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLsizei instances, GLint baseVertex = 0,  GLint baseInstance = 0) Q_DECL_OVERRIDE;
-    void enableAlphaCoverage() Q_DECL_OVERRIDE;
     void enableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void enablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void enablePrimitiveRestart(int primitiveRestartIndex) Q_DECL_OVERRIDE;
@@ -112,6 +110,7 @@ public:
     QVector<ShaderUniform> programUniformsAndLocations(GLuint programId) Q_DECL_OVERRIDE;
     QVector<ShaderStorageBlock> programShaderStorageBlocks(GLuint programId) Q_DECL_OVERRIDE;
     void releaseFrameBufferObject(GLuint frameBufferId) Q_DECL_OVERRIDE;
+    void setAlphaCoverageEnabled(bool enable) Q_DECL_OVERRIDE;
     void setClipPlane(int clipPlane, const QVector3D &normal, float distance) Q_DECL_OVERRIDE;
     void setSeamlessCubemap(bool enable) Q_DECL_OVERRIDE;
     void setVerticesPerPatch(GLint verticesPerPatch) Q_DECL_OVERRIDE;
diff --git a/src/render/graphicshelpers/graphicshelpergl3.cpp b/src/render/graphicshelpers/graphicshelpergl3.cpp
index 0eee70456..2b44bc3da 100644
--- a/src/render/graphicshelpers/graphicshelpergl3.cpp
+++ b/src/render/graphicshelpers/graphicshelpergl3.cpp
@@ -308,14 +308,10 @@ void GraphicsHelperGL3::frontFace(GLenum mode)
 
 }
 
-void GraphicsHelperGL3::enableAlphaCoverage()
+void GraphicsHelperGL3::setAlphaCoverageEnabled(bool enabled)
 {
-    m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
-}
-
-void GraphicsHelperGL3::disableAlphaCoverage()
-{
-    m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+    enabled ? m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE)
+            : m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
 }
 
 GLuint GraphicsHelperGL3::createFrameBufferObject()
diff --git a/src/render/graphicshelpers/graphicshelpergl3_3.cpp b/src/render/graphicshelpers/graphicshelpergl3_3.cpp
index c66ad601c..70c7cf53e 100644
--- a/src/render/graphicshelpers/graphicshelpergl3_3.cpp
+++ b/src/render/graphicshelpers/graphicshelpergl3_3.cpp
@@ -305,14 +305,10 @@ void GraphicsHelperGL3_3::frontFace(GLenum mode)
 
 }
 
-void GraphicsHelperGL3_3::enableAlphaCoverage()
+void GraphicsHelperGL3_3::setAlphaCoverageEnabled(bool enabled)
 {
-    m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
-}
-
-void GraphicsHelperGL3_3::disableAlphaCoverage()
-{
-    m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+    enabled ? m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE)
+            : m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
 }
 
 GLuint GraphicsHelperGL3_3::createFrameBufferObject()
diff --git a/src/render/graphicshelpers/graphicshelpergl3_3_p.h b/src/render/graphicshelpers/graphicshelpergl3_3_p.h
index 7509a91fc..d84a9ed72 100644
--- a/src/render/graphicshelpers/graphicshelpergl3_3_p.h
+++ b/src/render/graphicshelpers/graphicshelpergl3_3_p.h
@@ -88,7 +88,6 @@ public:
     void cullFace(GLenum mode) Q_DECL_OVERRIDE;
     void depthMask(GLenum mode) Q_DECL_OVERRIDE;
     void depthTest(GLenum mode) Q_DECL_OVERRIDE;
-    void disableAlphaCoverage() Q_DECL_OVERRIDE;
     void disableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void disablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void disablePrimitiveRestart() Q_DECL_OVERRIDE;
@@ -98,7 +97,6 @@ public:
     void drawBuffers(GLsizei n, const int *bufs) Q_DECL_OVERRIDE;
     void drawElements(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLint baseVertex = 0) Q_DECL_OVERRIDE;
     void drawElementsInstanced(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLsizei instances, GLint baseVertex = 0,  GLint baseInstance = 0) Q_DECL_OVERRIDE;
-    void enableAlphaCoverage() Q_DECL_OVERRIDE;
     void enableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void enablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void enablePrimitiveRestart(int primitiveRestartIndex) Q_DECL_OVERRIDE;
@@ -113,6 +111,7 @@ public:
     QVector<ShaderUniform> programUniformsAndLocations(GLuint programId) Q_DECL_OVERRIDE;
     QVector<ShaderStorageBlock> programShaderStorageBlocks(GLuint programId) Q_DECL_OVERRIDE;
     void releaseFrameBufferObject(GLuint frameBufferId) Q_DECL_OVERRIDE;
+    void setAlphaCoverageEnabled(bool enable) Q_DECL_OVERRIDE;
     void setClipPlane(int clipPlane, const QVector3D &normal, float distance) Q_DECL_OVERRIDE;
     void setSeamlessCubemap(bool enable) Q_DECL_OVERRIDE;
     void setVerticesPerPatch(GLint verticesPerPatch) Q_DECL_OVERRIDE;
diff --git a/src/render/graphicshelpers/graphicshelpergl3_p.h b/src/render/graphicshelpers/graphicshelpergl3_p.h
index c55a27637..49843055e 100644
--- a/src/render/graphicshelpers/graphicshelpergl3_p.h
+++ b/src/render/graphicshelpers/graphicshelpergl3_p.h
@@ -88,7 +88,6 @@ public:
     void cullFace(GLenum mode) Q_DECL_OVERRIDE;
     void depthMask(GLenum mode) Q_DECL_OVERRIDE;
     void depthTest(GLenum mode) Q_DECL_OVERRIDE;
-    void disableAlphaCoverage() Q_DECL_OVERRIDE;
     void disableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void disablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void disablePrimitiveRestart() Q_DECL_OVERRIDE;
@@ -98,7 +97,6 @@ public:
     void drawBuffers(GLsizei n, const int *bufs) Q_DECL_OVERRIDE;
     void drawElements(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLint baseVertex = 0) Q_DECL_OVERRIDE;
     void drawElementsInstanced(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLsizei instances, GLint baseVertex = 0,  GLint baseInstance = 0) Q_DECL_OVERRIDE;
-    void enableAlphaCoverage() Q_DECL_OVERRIDE;
     void enableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void enablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void enablePrimitiveRestart(int primitiveRestartIndex) Q_DECL_OVERRIDE;
@@ -113,6 +111,7 @@ public:
     QVector<ShaderUniform> programUniformsAndLocations(GLuint programId) Q_DECL_OVERRIDE;
     QVector<ShaderStorageBlock> programShaderStorageBlocks(GLuint programId) Q_DECL_OVERRIDE;
     void releaseFrameBufferObject(GLuint frameBufferId) Q_DECL_OVERRIDE;
+    void setAlphaCoverageEnabled(bool enable) Q_DECL_OVERRIDE;
     void setClipPlane(int clipPlane, const QVector3D &normal, float distance) Q_DECL_OVERRIDE;
     void setSeamlessCubemap(bool enable) Q_DECL_OVERRIDE;
     void setVerticesPerPatch(GLint verticesPerPatch) Q_DECL_OVERRIDE;
diff --git a/src/render/graphicshelpers/graphicshelpergl4.cpp b/src/render/graphicshelpers/graphicshelpergl4.cpp
index 066603ab4..7e04d7a6c 100644
--- a/src/render/graphicshelpers/graphicshelpergl4.cpp
+++ b/src/render/graphicshelpers/graphicshelpergl4.cpp
@@ -298,14 +298,10 @@ void GraphicsHelperGL4::frontFace(GLenum mode)
 
 }
 
-void GraphicsHelperGL4::enableAlphaCoverage()
+void GraphicsHelperGL4::setAlphaCoverageEnabled(bool enabled)
 {
-    m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
-}
-
-void GraphicsHelperGL4::disableAlphaCoverage()
-{
-    m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+    enabled ? m_funcs->glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE)
+            : m_funcs->glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
 }
 
 GLuint GraphicsHelperGL4::createFrameBufferObject()
diff --git a/src/render/graphicshelpers/graphicshelpergl4_p.h b/src/render/graphicshelpers/graphicshelpergl4_p.h
index 0ab3ef5db..81553abc3 100644
--- a/src/render/graphicshelpers/graphicshelpergl4_p.h
+++ b/src/render/graphicshelpers/graphicshelpergl4_p.h
@@ -87,7 +87,6 @@ public:
     void cullFace(GLenum mode) Q_DECL_OVERRIDE;
     void depthMask(GLenum mode) Q_DECL_OVERRIDE;
     void depthTest(GLenum mode) Q_DECL_OVERRIDE;
-    void disableAlphaCoverage() Q_DECL_OVERRIDE;
     void disableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void disablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void disablePrimitiveRestart() Q_DECL_OVERRIDE;
@@ -97,7 +96,6 @@ public:
     void drawBuffers(GLsizei n, const int *bufs) Q_DECL_OVERRIDE;
     void drawElements(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLint baseVertex = 0) Q_DECL_OVERRIDE;
     void drawElementsInstanced(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void *indices, GLsizei instances, GLint baseVertex = 0,  GLint baseInstance = 0) Q_DECL_OVERRIDE;
-    void enableAlphaCoverage() Q_DECL_OVERRIDE;
     void enableClipPlane(int clipPlane) Q_DECL_OVERRIDE;
     void enablei(GLenum cap, GLuint index) Q_DECL_OVERRIDE;
     void enablePrimitiveRestart(int primitiveRestartIndex) Q_DECL_OVERRIDE;
@@ -112,6 +110,7 @@ public:
     QVector<ShaderUniform> programUniformsAndLocations(GLuint programId) Q_DECL_OVERRIDE;
     QVector<ShaderStorageBlock> programShaderStorageBlocks(GLuint programId) Q_DECL_OVERRIDE;
     void releaseFrameBufferObject(GLuint frameBufferId) Q_DECL_OVERRIDE;
+    void setAlphaCoverageEnabled(bool enable) Q_DECL_OVERRIDE;
     void setClipPlane(int clipPlane, const QVector3D &normal, float distance) Q_DECL_OVERRIDE;
     void setSeamlessCubemap(bool enable) Q_DECL_OVERRIDE;
     void setVerticesPerPatch(GLint verticesPerPatch) Q_DECL_OVERRIDE;
diff --git a/src/render/graphicshelpers/graphicshelperinterface_p.h b/src/render/graphicshelpers/graphicshelperinterface_p.h
index 584b68475..9f508876a 100644
--- a/src/render/graphicshelpers/graphicshelperinterface_p.h
+++ b/src/render/graphicshelpers/graphicshelperinterface_p.h
@@ -98,7 +98,6 @@ public:
     virtual void    cullFace(GLenum mode) = 0;
     virtual void    depthMask(GLenum mode) = 0;
     virtual void    depthTest(GLenum mode) = 0;
-    virtual void    disableAlphaCoverage() = 0;
     virtual void    disableClipPlane(int clipPlane) = 0;
     virtual void    disablei(GLenum cap, GLuint index) = 0;
     virtual void    disablePrimitiveRestart() = 0;
@@ -108,7 +107,6 @@ public:
     virtual void    drawBuffers(GLsizei n, const int *bufs) = 0;
     virtual void    drawElements(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void * indices, GLint baseVertex = 0) = 0;
     virtual void    drawElementsInstanced(GLenum primitiveType, GLsizei primitiveCount, GLint indexType, void * indices, GLsizei instances, GLint baseVertex = 0, GLint baseInstance = 0) = 0;
-    virtual void    enableAlphaCoverage() = 0;
     virtual void    enableClipPlane(int clipPlane) = 0;
     virtual void    enablei(GLenum cap, GLuint index) = 0;
     virtual void    enablePrimitiveRestart(int primitiveRestartIndex) = 0;
@@ -123,6 +121,7 @@ public:
     virtual QVector<ShaderUniformBlock> programUniformBlocks(GLuint programId) = 0;
     virtual QVector<ShaderStorageBlock> programShaderStorageBlocks(GLuint programId) = 0;
     virtual void    releaseFrameBufferObject(GLuint frameBufferId) = 0;
+    virtual void    setAlphaCoverageEnabled(bool enable) = 0;
     virtual void    setClipPlane(int clipPlane, const QVector3D &normal, float distance) = 0;
     virtual void    setSeamlessCubemap(bool enable) = 0;
     virtual void    setVerticesPerPatch(GLint verticesPerPatch) = 0;
diff --git a/src/render/renderstates/renderstates.cpp b/src/render/renderstates/renderstates.cpp
index 94e272cdd..bc84d9779 100644
--- a/src/render/renderstates/renderstates.cpp
+++ b/src/render/renderstates/renderstates.cpp
@@ -182,7 +182,13 @@ void StencilTest::apply(GraphicsContext *gc) const
 
 void AlphaCoverage::apply(GraphicsContext *gc) const
 {
-    gc->enableAlphaCoverage();
+    gc->setAlphaCoverageEnabled(m_1);
+}
+
+void AlphaCoverage::updateProperty(const char *name, const QVariant &value)
+{
+    if (name == QByteArrayLiteral("enabled"))
+        m_1 = value.toBool();
 }
 
 void PointSize::apply(GraphicsContext *gc) const
diff --git a/src/render/renderstates/renderstates_p.h b/src/render/renderstates/renderstates_p.h
index aed7e2ee1..308f1957b 100644
--- a/src/render/renderstates/renderstates_p.h
+++ b/src/render/renderstates/renderstates_p.h
@@ -168,10 +168,11 @@ public:
     virtual void apply(GraphicsContext *gc) const Q_DECL_OVERRIDE;
 };
 
-class Q_AUTOTEST_EXPORT AlphaCoverage : public MaskedRenderState<AlphaCoverage, AlphaCoverageStateMask>
+class Q_AUTOTEST_EXPORT AlphaCoverage : public GenericState1<AlphaCoverage, AlphaCoverageStateMask, GLboolean>
 {
 public:
     void apply(GraphicsContext *gc) const Q_DECL_OVERRIDE;
+    void updateProperty(const char *name, const QVariant &value) Q_DECL_OVERRIDE;
 };
 
 class Q_AUTOTEST_EXPORT PointSize : public GenericState2<PointSize, PointSizeMask, bool, GLfloat>
diff --git a/src/render/renderstates/renderstateset.cpp b/src/render/renderstates/renderstateset.cpp
index 187017ddb..d68600aeb 100644
--- a/src/render/renderstates/renderstateset.cpp
+++ b/src/render/renderstates/renderstateset.cpp
@@ -229,7 +229,7 @@ void RenderStateSet::resetMasked(StateMaskSet maskOfStatesToReset, GraphicsConte
     }
 
     if (maskOfStatesToReset & AlphaCoverageStateMask) {
-        gc->disableAlphaCoverage();
+        gc->setAlphaCoverageEnabled(false);
     }
 
     if (maskOfStatesToReset & PointSizeMask) {
@@ -374,6 +374,10 @@ RenderStateImpl* RenderStateImpl::getOrCreateState(QRenderState *renderState)
 RenderStateImpl* RenderStateImpl::getOrCreateState(const Qt3DRender::QRenderStateCreatedChangeBasePtr change)
 {
     switch (change->type()) {
+    case QRenderStatePrivate::AlphaCoverage: {
+        return getOrCreateRenderStateImpl<AlphaCoverage>(change->isNodeEnabled());
+    }
+
     case QRenderStatePrivate::AlphaTest: {
         const auto typedChange = qSharedPointerCast<Qt3DRender::QRenderStateCreatedChange<QAlphaTestData>>(change);
         const auto &data = typedChange->data;
@@ -412,8 +416,7 @@ RenderStateImpl* RenderStateImpl::getOrCreateState(const Qt3DRender::QRenderStat
         return getOrCreateRenderStateImpl<DepthTest>(data.depthFunction);
     }
 
-    // TODO: Fix AlphaCoverage and Dithering states
-    case QRenderStatePrivate::AlphaCoverage:
+    // TODO: Fix Dithering state
     case QRenderStatePrivate::Dithering:
     case QRenderStatePrivate::FrontFace: {
         const auto typedChange = qSharedPointerCast<Qt3DRender::QRenderStateCreatedChange<QFrontFaceData>>(change);