From 6a8c7a87059c279bf7aba0a5092b5de41ff9b815 Mon Sep 17 00:00:00 2001
From: Enrico Turri <enricoturri@seznam.cz>
Date: Mon, 3 Jun 2019 13:53:30 +0200
Subject: [PATCH] Fixed race condition while compressing texture data and
 sending them to the GPU

---
 src/slic3r/GUI/GLTexture.cpp | 8 ++++++--
 src/slic3r/GUI/GLTexture.hpp | 3 ++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/slic3r/GUI/GLTexture.cpp b/src/slic3r/GUI/GLTexture.cpp
index 469e192b5..78de38d54 100644
--- a/src/slic3r/GUI/GLTexture.cpp
+++ b/src/slic3r/GUI/GLTexture.cpp
@@ -55,7 +55,7 @@ bool GLTexture::Compressor::unsent_compressed_data_available() const
 {
     for (const Level& level : m_levels)
     {
-        if (!level.sent_to_gpu && (level.compressed_data.size() > 0))
+        if (!level.sent_to_gpu && level.compressed)
             return true;
     }
 
@@ -64,12 +64,14 @@ bool GLTexture::Compressor::unsent_compressed_data_available() const
 
 void GLTexture::Compressor::send_compressed_data_to_gpu()
 {
+    // this method should be called inside the main thread of Slicer or a new OpenGL context (sharing resources) would be needed
+
     glsafe(::glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
     glsafe(::glBindTexture(GL_TEXTURE_2D, m_texture.m_id));
     for (int i = 0; i < (int)m_levels.size(); ++i)
     {
         Level& level = m_levels[i];
-        if (!level.sent_to_gpu && (level.compressed_data.size() > 0))
+        if (!level.sent_to_gpu && level.compressed)
         {
             glsafe(::glCompressedTexSubImage2D(GL_TEXTURE_2D, (GLint)i, 0, 0, (GLsizei)level.w, (GLsizei)level.h, GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, (GLsizei)level.compressed_data.size(), (const GLvoid*)level.compressed_data.data()));
             glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, i));
@@ -77,6 +79,7 @@ void GLTexture::Compressor::send_compressed_data_to_gpu()
             level.sent_to_gpu = true;
             // we are done with the compressed data, we can discard it
             level.compressed_data.clear();
+            level.compressed = false;
         }
     }
     glsafe(::glBindTexture(GL_TEXTURE_2D, 0));
@@ -100,6 +103,7 @@ void GLTexture::Compressor::compress()
 
         // we are done with the source data, we can discard it
         level.src_data.clear();
+        level.compressed = true;
     }
 
     m_is_compressing = false;
diff --git a/src/slic3r/GUI/GLTexture.hpp b/src/slic3r/GUI/GLTexture.hpp
index ed2070a44..d1ff366c3 100644
--- a/src/slic3r/GUI/GLTexture.hpp
+++ b/src/slic3r/GUI/GLTexture.hpp
@@ -20,9 +20,10 @@ namespace GUI {
                 unsigned int h;
                 std::vector<unsigned char> src_data;
                 std::vector<unsigned char> compressed_data;
+                bool compressed;
                 bool sent_to_gpu;
 
-                Level(unsigned int w, unsigned int h, const std::vector<unsigned char>& data) : w(w), h(h), src_data(data), sent_to_gpu(false) {}
+                Level(unsigned int w, unsigned int h, const std::vector<unsigned char>& data) : w(w), h(h), src_data(data), compressed(false), sent_to_gpu(false) {}
             };
 
             GLTexture& m_texture;