fdo#81182: glTF window size does not match with the scene size after resizing

When viewport changed it is necessary to resize the whole scene.
Calling releasFbo removes size dependent objects and triggers
creating the new ones with the new size.

Change-Id: Ibd8be1e92be92da31add4a30aa799f0995b1cc88
(cherry picked from commit 3cd7c0f6b6cdb8ebc6c72d2ffe1e0bc18968e27b)
Reviewed-on: https://gerrit.libreoffice.org/10352
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

2 files changed, 72 insertions, 0 deletions

diff --git a/external/libgltf/UnpackedTarball_libgltf.mk b/external/libgltf/UnpackedTarball_libgltf.mk
index 176c1d15246b..a7565ea09efc 100644
--- a/external/libgltf/UnpackedTarball_libgltf.mk
+++ b/external/libgltf/UnpackedTarball_libgltf.mk
@@ -16,6 +16,7 @@ $(eval $(call gb_UnpackedTarball_set_patchflags,libgltf,--binary))
 $(eval $(call gb_UnpackedTarball_set_patchlevel,libgltf,1))
 
 $(eval $(call gb_UnpackedTarball_add_patches,libgltf,\
+	external/libgltf/pathces/fix_rendering_of_resized_model.patch \
 ))
 
 # vim: set noet sw=4 ts=4:
diff --git a/external/libgltf/pathces/fix_rendering_of_resized_model.patch b/external/libgltf/pathces/fix_rendering_of_resized_model.patch
new file mode 100644
index 000000000000..57af9f9e08eb
--- /dev/null
+++ b/external/libgltf/pathces/fix_rendering_of_resized_model.patch
@@ -0,0 +1,71 @@
+diff -ur libgltf.org/src/RenderScene.cpp libgltf/src/RenderScene.cpp
+--- libgltf.org/src/RenderScene.cpp	2014-07-15 17:33:12.615059856 +0200
++++ libgltf/src/RenderScene.cpp	2014-07-15 22:24:20.862307666 +0200
+@@ -639,7 +639,7 @@
+     , pScene(0)
+     , mLoadJson()
+     , mBindBufferMap()
+-    , viewport()
++    , mCurrentViewport()
+     , fbo()
+     , mEnableTransparency(false)
+     , mEnableRotation(false)
+@@ -1555,10 +1555,9 @@
+         pFPSCounter->timeStamp();
+     }
+ #endif
+-    viewport = *((glTFViewport*)lpParam);
+     {
+         TRACE_TIME;
+-        status = initSSAAFrameBuf(&viewport);
++        status = initSSAAFrameBuf(((glTFViewport*)lpParam));
+         if (LIBGLTF_SUCCESS != status)
+             return status;
+     }
+@@ -1569,6 +1568,15 @@
+ {
+     if (0 == pViewport->width)
+         return LIBGLTF_INVALID_SIZE;
++
++    // When viewport changes we need to release fbo and create a new one
++    if( mCurrentViewport.x != pViewport->x || mCurrentViewport.y != pViewport->y ||
++        mCurrentViewport.width != pViewport->width || mCurrentViewport.height != pViewport->height )
++    {
++        fbo.releaseFbo();
++        mCurrentViewport = *pViewport;
++    }
++
+ #if DEFAULT_VIEW
+     unsigned int width  = SSAA * DEFAULT_VIEW;
+     unsigned int height = (SSAA * DEFAULT_VIEW *
+@@ -1730,14 +1738,14 @@
+ #if ENABLE_FPS
+     if (0 != pFPSCounter)
+     {
+-        pFPSCounter->printFPS(&viewport);
++        pFPSCounter->printFPS(&mCurrentViewport);
+     }
+ #endif
+ 
+     {
+         TRACE_TIME;
+-        glViewport(viewport.x, viewport.y,
+-                   viewport.width, viewport.height);
++        glViewport(mCurrentViewport.x, mCurrentViewport.y,
++                   mCurrentViewport.width, mCurrentViewport.height);
+         glBindFramebuffer(GL_FRAMEBUFFER, 0);
+         fbo.renderFboTexture();
+     }
+Only in libgltf/src: RenderScene.cpp~
+diff -ur libgltf.org/src/RenderScene.h libgltf/src/RenderScene.h
+--- libgltf.org/src/RenderScene.h	2014-07-15 17:33:12.615059856 +0200
++++ libgltf/src/RenderScene.h	2014-07-15 22:18:01.306324010 +0200
+@@ -349,7 +349,7 @@
+     std::map<std::string, BindBufferInfo> mBindBufferMap;
+ 
+     static ShaderProgram mShaderProgram;
+-    glTFViewport viewport;
++    glTFViewport mCurrentViewport;
+     RenderWithFBO fbo;
+ 
+     bool mEnableTransparency;