Replace glFinish with OpenGL fences.

[mlt] / src / modules / opengl / filter_glsl_manager.cpp

diff --git a/src/modules/opengl/filter_glsl_manager.cpp b/src/modules/opengl/filter_glsl_manager.cpp
index 3cf7568347b76b605f546f1cdaf70bfe3399ab1c..68ef63dc4f56a013fe47fe8d0f96324202e92c4b 100644 (file)
--- a/src/modules/opengl/filter_glsl_manager.cpp
+++ b/src/modules/opengl/filter_glsl_manager.cpp
@@ -51,6 +51,7 @@ GlslManager::GlslManager()
        , pbo(0)
        , initEvent(0)
        , closeEvent(0)
+       , prev_sync(NULL)
 {
        mlt_filter filter = get_filter();
        if ( filter ) {
@@ -76,6 +77,9 @@ GlslManager::~GlslManager()
 //             delete (glsl_texture) texture_list.pop_back();
        delete initEvent;
        delete closeEvent;
+       if (prev_sync != NULL) {
+               glDeleteSync( prev_sync );
+       }
 }
 
 GlslManager* GlslManager::get_instance()
@@ -194,6 +198,11 @@ void GlslManager::release_texture(glsl_texture texture)
        texture->used = 0;
 }
 
+void GlslManager::delete_sync(GLsync sync)
+{
+       glDeleteSync(sync);
+}
+
 glsl_pbo GlslManager::get_pbo(int size)
 {
        lock();
@@ -408,9 +417,18 @@ int GlslManager::render_frame_texture(mlt_service service, mlt_frame frame, int
        glBindFramebuffer( GL_FRAMEBUFFER, 0 );
        check_error();
 
+       // Make sure we never have more than one frame pending at any time.
+       // This ensures we do not swamp the GPU with so much work
+       // that we cannot actually display the frames we generate.
+       if (prev_sync != NULL) {
+               glFlush();
+               glClientWaitSync( prev_sync, 0, GL_TIMEOUT_IGNORED );
+               glDeleteSync( prev_sync );
+       }
        render_fbo( service, chain, fbo->fbo, width, height );
+       prev_sync = glFenceSync( GL_SYNC_GPU_COMMANDS_COMPLETE, 0 );
+       GLsync sync = glFenceSync( GL_SYNC_GPU_COMMANDS_COMPLETE, 0 );
 
-       glFinish();
        check_error();
        glBindFramebuffer( GL_FRAMEBUFFER, 0 );
        check_error();
@@ -420,6 +438,8 @@ int GlslManager::render_frame_texture(mlt_service service, mlt_frame frame, int
        mlt_frame_set_image( frame, *image, 0, NULL );
        mlt_properties_set_data( MLT_FRAME_PROPERTIES(frame), "movit.convert.texture", texture, 0,
                (mlt_destructor) GlslManager::release_texture, NULL );
+       mlt_properties_set_data( MLT_FRAME_PROPERTIES(frame), "movit.convert.fence", sync, 0,
+               (mlt_destructor) GlslManager::delete_sync, NULL );
 
        return 0;
 }