opengl: track state of active and bound textures in context

Add TextureState which is responsible to track the state of
texture binding (and unbinding) and changing the current active
texture unit. This is necessary because all GL calls reset the
internal state without checking what the current state actually
is and this can accumulate to a large amount of overhead.

We also unbound the textures (glBindTexture with 0 as ID) after
every operation which is also a major unneeded overhead which is
fixed by this commit.

Change-Id: I770a6a744c0c41850c576b928f027375962088aa
Reviewed-on: https://gerrit.libreoffice.org/24503
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

3 files changed, 44 insertions, 47 deletions

diff --git a/vcl/opengl/program.cxx b/vcl/opengl/program.cxx
index c8b0583f56a2..c4f5c0e5ec02 100644
--- a/vcl/opengl/program.cxx
+++ b/vcl/opengl/program.cxx
@@ -7,9 +7,11 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-#include <opengl/program.hxx>
+#include "opengl/program.hxx"
+#include "opengl/RenderState.hxx"
 
 #include <vcl/opengl/OpenGLHelper.hxx>
+#include <vcl/opengl/OpenGLContext.hxx>
 
 #include <glm/glm.hpp>
 #include <glm/gtc/type_ptr.hpp>
@@ -62,19 +64,11 @@ bool OpenGLProgram::Use()
 bool OpenGLProgram::Clean()
 {
     // unbind all textures
-    if( !maTextures.empty() )
+    for (OpenGLTexture& rTexture : maTextures)
     {
-        int nIndex( maTextures.size() - 1 );
-        TextureList::reverse_iterator it( maTextures.rbegin() );
-        while( it != maTextures.rend() )
-        {
-            glActiveTexture( GL_TEXTURE0 + nIndex-- );
-            CHECK_GL_ERROR();
-            it->Unbind();
-            ++it;
-        }
-        maTextures.clear();
+        rTexture.Unbind();
     }
+    maTextures.clear();
 
     // disable any enabled vertex attrib array
     if( mnEnabledAttribs )
@@ -252,10 +246,12 @@ void OpenGLProgram::SetTexture( const OString& rName, OpenGLTexture& rTexture )
 
     glUniform1i( nUniform, nIndex );
     CHECK_GL_ERROR();
-    glActiveTexture( GL_TEXTURE0 + nIndex );
-    CHECK_GL_ERROR();
+
+    std::unique_ptr<RenderState>& rState = OpenGLContext::getVCLContext()->state();
+    rState->texture().active(nIndex);
+
     rTexture.Bind();
-    maTextures.push_back( rTexture );
+    maTextures.push_back(rTexture);
 }
 
 void OpenGLProgram::SetTransform(
diff --git a/vcl/opengl/texture.cxx b/vcl/opengl/texture.cxx
index 232b2cd002f0..e9fca75befa1 100644
--- a/vcl/opengl/texture.cxx
+++ b/vcl/opengl/texture.cxx
@@ -29,6 +29,8 @@
 #include "opengl/framebuffer.hxx"
 #include "opengl/texture.hxx"
 #include "opengl/zone.hxx"
+#include "opengl/RenderState.hxx"
+
 namespace
 {
 
@@ -47,10 +49,11 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nWidth, int nHeight, bool bAllocate )
 {
     OpenGLVCLContextZone aContextZone;
 
-    glGenTextures( 1, &mnTexture );
-    CHECK_GL_ERROR();
-    glBindTexture( GL_TEXTURE_2D, mnTexture );
-    CHECK_GL_ERROR();
+    auto& rState = OpenGLContext::getVCLContext()->state();
+    rState->texture().generate(mnTexture);
+    rState->texture().active(0);
+    rState->texture().bind(mnTexture);
+
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
     CHECK_GL_ERROR();
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
@@ -64,8 +67,6 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nWidth, int nHeight, bool bAllocate )
         glTexImage2D( GL_TEXTURE_2D, 0, constInternalFormat, nWidth, nHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr );
         CHECK_GL_ERROR();
     }
-    glBindTexture( GL_TEXTURE_2D, 0 );
-    CHECK_GL_ERROR();
 
     VCL_GL_INFO( "OpenGLTexture " << mnTexture << " " << nWidth << "x" << nHeight << " allocate" );
 }
@@ -84,10 +85,11 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nX, int nY, int nWidth, int nHeight )
     // FIXME We need the window height here
     // nY = GetHeight() - nHeight - nY;
 
-    glGenTextures( 1, &mnTexture );
-    CHECK_GL_ERROR();
-    glBindTexture( GL_TEXTURE_2D, mnTexture );
-    CHECK_GL_ERROR();
+    auto& rState = OpenGLContext::getVCLContext()->state();
+    rState->texture().generate(mnTexture);
+    rState->texture().active(0);
+    rState->texture().bind(mnTexture);
+
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
     CHECK_GL_ERROR();
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
@@ -98,8 +100,6 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nX, int nY, int nWidth, int nHeight )
     CHECK_GL_ERROR();
     glCopyTexImage2D( GL_TEXTURE_2D, 0, constInternalFormat, nX, nY, nWidth, nHeight, 0 );
     CHECK_GL_ERROR();
-    glBindTexture( GL_TEXTURE_2D, 0 );
-    CHECK_GL_ERROR();
 
     VCL_GL_INFO( "OpenGLTexture " << mnTexture << " " << nWidth << "x" << nHeight << " from x" << nX << ", y" << nY );
 }
@@ -115,10 +115,11 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nWidth, int nHeight, int nFormat, int
 {
     OpenGLVCLContextZone aContextZone;
 
-    glGenTextures( 1, &mnTexture );
-    CHECK_GL_ERROR();
-    glBindTexture( GL_TEXTURE_2D, mnTexture );
-    CHECK_GL_ERROR();
+    auto& rState = OpenGLContext::getVCLContext()->state();
+    rState->texture().generate(mnTexture);
+    rState->texture().active(0);
+    rState->texture().bind(mnTexture);
+
     glPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
     CHECK_GL_ERROR();
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
@@ -131,8 +132,6 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nWidth, int nHeight, int nFormat, int
     CHECK_GL_ERROR();
     glTexImage2D( GL_TEXTURE_2D, 0, constInternalFormat, mnWidth, mnHeight, 0, nFormat, nType, pData );
     CHECK_GL_ERROR();
-    glBindTexture( GL_TEXTURE_2D, 0 );
-    CHECK_GL_ERROR();
 
     VCL_GL_INFO( "OpenGLTexture " << mnTexture << " " << nWidth << "x" << nHeight << " from data" );
 }
@@ -187,8 +186,8 @@ void ImplOpenGLTexture::Dispose()
                 glDeleteRenderbuffers( 1, &mnOptStencil );
                 mnOptStencil = 0;
             }
-            glDeleteTextures( 1, &mnTexture );
-
+            auto& rState = pContext->state();
+            rState->texture().unbindAndDelete(mnTexture);
             mnTexture = 0;
         }
         else
@@ -203,14 +202,15 @@ bool ImplOpenGLTexture::InsertBuffer(int nX, int nY, int nWidth, int nHeight, in
 {
     if (!pData || mnTexture == 0)
         return false;
-    glBindTexture(GL_TEXTURE_2D, mnTexture);
-    CHECK_GL_ERROR();
+
+    rtl::Reference<OpenGLContext> xContext = OpenGLContext::getVCLContext();
+    xContext->state()->texture().active(0);
+    xContext->state()->texture().bind(mnTexture);
+
     glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
     CHECK_GL_ERROR();
     glTexSubImage2D(GL_TEXTURE_2D, 0, nX, mnHeight - nY - nHeight, nWidth, nHeight, nFormat, nType, pData);
     CHECK_GL_ERROR();
-    glBindTexture(GL_TEXTURE_2D, 0);
-    CHECK_GL_ERROR();
 
     VCL_GL_INFO( "OpenGLTexture " << mnTexture << " Insert buff. to " << nX << " " << nY
                                              << " size " << nWidth << "x" << nHeight << " from data" );
@@ -492,10 +492,10 @@ void OpenGLTexture::SetFilter( GLenum nFilter )
 
 void OpenGLTexture::Bind()
 {
-    if( mpImpl )
+    if (mpImpl)
     {
-        glBindTexture( GL_TEXTURE_2D, mpImpl->mnTexture );
-        CHECK_GL_ERROR();
+        std::unique_ptr<RenderState>& rState = OpenGLContext::getVCLContext()->state();
+        rState->texture().bind(mpImpl->mnTexture);
     }
     else
         VCL_GL_INFO( "OpenGLTexture::Binding invalid texture" );
@@ -505,10 +505,10 @@ void OpenGLTexture::Bind()
 
 void OpenGLTexture::Unbind()
 {
-    if( mpImpl )
+    if (mpImpl)
     {
-        glBindTexture( GL_TEXTURE_2D, 0 );
-        CHECK_GL_ERROR();
+        std::unique_ptr<RenderState>& rState = OpenGLContext::getVCLContext()->state();
+        rState->texture().unbind(mpImpl->mnTexture);
     }
 }
 
diff --git a/vcl/opengl/x11/gdiimpl.cxx b/vcl/opengl/x11/gdiimpl.cxx
index fc49e2520e58..61dba9b78db3 100644
--- a/vcl/opengl/x11/gdiimpl.cxx
+++ b/vcl/opengl/x11/gdiimpl.cxx
@@ -22,6 +22,7 @@
 #include <opengl/texture.hxx>
 #include <opengl/x11/gdiimpl.hxx>
 #include <opengl/x11/salvd.hxx>
+#include "opengl/RenderState.hxx"
 
 #include <vcl/opengl/OpenGLContext.hxx>
 #include <vcl/opengl/OpenGLHelper.hxx>
@@ -144,8 +145,8 @@ bool X11OpenGLSalGraphicsImpl::RenderPixmap(X11Pixmap* pPixmap, X11Pixmap* pMask
 
     rCombo.mpTexture.reset(new OpenGLTexture(pPixmap->GetWidth(), pPixmap->GetHeight(), false));
 
-    glActiveTexture( GL_TEXTURE0 );
-    CHECK_GL_ERROR();
+    mpContext->state()->texture().active(0);
+
     rCombo.mpTexture->Bind();
     glXBindTexImageEXT( pDisplay, pGlxPixmap, GLX_FRONT_LEFT_EXT, nullptr );
     rCombo.mpTexture->Unbind();