ENABLE_THUMBNAIL_GENERATOR -> Generate thumbnails using GLEW_EXT_framebuffer_object on graphic cards supporting it

src/slic3r/GUI/GLCanvas3D.cpp

@@ -1653,10 +1653,12 @@ void GLCanvas3D::render()
 #if ENABLE_THUMBNAIL_GENERATOR
 void GLCanvas3D::render_thumbnail(ThumbnailData& thumbnail_data, unsigned int w, unsigned int h, bool printable_only, bool parts_only, bool transparent_background)
 {
-    if (GLCanvas3DManager::are_framebuffers_supported())
+    switch (GLCanvas3DManager::get_framebuffers_type())
-        _render_thumbnail_framebuffer(thumbnail_data, w, h, printable_only, parts_only, transparent_background);
+    {
-    else
+    case GLCanvas3DManager::FB_Arb: { _render_thumbnail_framebuffer(thumbnail_data, w, h, printable_only, parts_only, transparent_background); break; }
-        _render_thumbnail_legacy(thumbnail_data, w, h, printable_only, parts_only, transparent_background);
+    case GLCanvas3DManager::FB_Ext: { _render_thumbnail_framebuffer_ext(thumbnail_data, w, h, printable_only, parts_only, transparent_background); break; }
+    default: { _render_thumbnail_legacy(thumbnail_data, w, h, printable_only, parts_only, transparent_background); break; }
+    }
 }
 #endif // ENABLE_THUMBNAIL_GENERATOR
 
@@ -3772,6 +3774,110 @@ void GLCanvas3D::_render_thumbnail_framebuffer(ThumbnailData& thumbnail_data, un
         glsafe(::glDisable(GL_MULTISAMPLE));
 }
 
+void GLCanvas3D::_render_thumbnail_framebuffer_ext(ThumbnailData& thumbnail_data, unsigned int w, unsigned int h, bool printable_only, bool parts_only, bool transparent_background)
+{
+    thumbnail_data.set(w, h);
+    if (!thumbnail_data.is_valid())
+        return;
+
+    bool multisample = m_multisample_allowed;
+    if (multisample)
+        glsafe(::glEnable(GL_MULTISAMPLE));
+
+    GLint max_samples;
+    glsafe(::glGetIntegerv(GL_MAX_SAMPLES_EXT, &max_samples));
+    GLsizei num_samples = max_samples / 2;
+
+    GLuint render_fbo;
+    glsafe(::glGenFramebuffersEXT(1, &render_fbo));
+    glsafe(::glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, render_fbo));
+
+    GLuint render_tex = 0;
+    GLuint render_tex_buffer = 0;
+    if (multisample)
+    {
+        // use renderbuffer instead of texture to avoid the need to use glTexImage2DMultisample which is available only since OpenGL 3.2
+        glsafe(::glGenRenderbuffersEXT(1, &render_tex_buffer));
+        glsafe(::glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, render_tex_buffer));
+        glsafe(::glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, num_samples, GL_RGBA8, w, h));
+        glsafe(::glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_RENDERBUFFER_EXT, render_tex_buffer));
+    }
+    else
+    {
+        glsafe(::glGenTextures(1, &render_tex));
+        glsafe(::glBindTexture(GL_TEXTURE_2D, render_tex));
+        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr));
+        glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
+        glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
+        glsafe(::glFramebufferTexture2D(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, render_tex, 0));
+    }
+
+    GLuint render_depth;
+    glsafe(::glGenRenderbuffersEXT(1, &render_depth));
+    glsafe(::glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, render_depth));
+    if (multisample)
+        glsafe(::glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, num_samples, GL_DEPTH_COMPONENT24, w, h));
+    else
+        glsafe(::glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, w, h));
+
+    glsafe(::glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, render_depth));
+
+    GLenum drawBufs[] = { GL_COLOR_ATTACHMENT0 };
+    glsafe(::glDrawBuffers(1, drawBufs));
+
+    if (::glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) == GL_FRAMEBUFFER_COMPLETE_EXT)
+    {
+        render_volumes_in_thumbnail(m_shader, m_volumes.volumes, thumbnail_data, printable_only, parts_only, transparent_background);
+
+        if (multisample)
+        {
+            GLuint resolve_fbo;
+            glsafe(::glGenFramebuffersEXT(1, &resolve_fbo));
+            glsafe(::glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, resolve_fbo));
+
+            GLuint resolve_tex;
+            glsafe(::glGenTextures(1, &resolve_tex));
+            glsafe(::glBindTexture(GL_TEXTURE_2D, resolve_tex));
+            glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr));
+            glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
+            glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
+            glsafe(::glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, resolve_tex, 0));
+
+            glsafe(::glDrawBuffers(1, drawBufs));
+
+            if (::glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) == GL_FRAMEBUFFER_COMPLETE_EXT)
+            {
+                glsafe(::glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, render_fbo));
+                glsafe(::glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, resolve_fbo));
+                glsafe(::glBlitFramebufferEXT(0, 0, w, h, 0, 0, w, h, GL_COLOR_BUFFER_BIT, GL_LINEAR));
+
+                glsafe(::glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, resolve_fbo));
+                glsafe(::glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, (void*)thumbnail_data.pixels.data()));
+            }
+
+            glsafe(::glDeleteTextures(1, &resolve_tex));
+            glsafe(::glDeleteFramebuffersEXT(1, &resolve_fbo));
+        }
+        else
+            glsafe(::glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, (void*)thumbnail_data.pixels.data()));
+
+#if ENABLE_THUMBNAIL_GENERATOR_DEBUG_OUTPUT
+        debug_output_thumbnail(thumbnail_data);
+#endif // ENABLE_THUMBNAIL_GENERATOR_DEBUG_OUTPUT
+    }
+
+    glsafe(::glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0));
+    glsafe(::glDeleteRenderbuffersEXT(1, &render_depth));
+    if (render_tex_buffer != 0)
+        glsafe(::glDeleteRenderbuffersEXT(1, &render_tex_buffer));
+    if (render_tex != 0)
+        glsafe(::glDeleteTextures(1, &render_tex));
+    glsafe(::glDeleteFramebuffersEXT(1, &render_fbo));
+
+    if (multisample)
+        glsafe(::glDisable(GL_MULTISAMPLE));
+}
+
 void GLCanvas3D::_render_thumbnail_legacy(ThumbnailData& thumbnail_data, unsigned int w, unsigned int h, bool printable_only, bool parts_only, bool transparent_background)
 {
     // check that thumbnail size does not exceed the default framebuffer size

src/slic3r/GUI/GLCanvas3D.hpp

@@ -685,7 +685,9 @@ private:
 #if ENABLE_THUMBNAIL_GENERATOR
     // render thumbnail using an off-screen framebuffer
     void _render_thumbnail_framebuffer(ThumbnailData& thumbnail_data, unsigned int w, unsigned int h, bool printable_only, bool parts_only, bool transparent_background);
-        // render thumbnail using the default framebuffer
+    // render thumbnail using an off-screen framebuffer when GLEW_EXT_framebuffer_object is supported
+    void _render_thumbnail_framebuffer_ext(ThumbnailData& thumbnail_data, unsigned int w, unsigned int h, bool printable_only, bool parts_only, bool transparent_background);
+    // render thumbnail using the default framebuffer
     void _render_thumbnail_legacy(ThumbnailData& thumbnail_data, unsigned int w, unsigned int h, bool printable_only, bool parts_only, bool transparent_background);
 #endif // ENABLE_THUMBNAIL_GENERATOR
 

src/slic3r/GUI/GLCanvas3DManager.cpp

@@ -189,7 +189,7 @@ std::string GLCanvas3DManager::GLInfo::to_string(bool format_as_html, bool exten
 
 GLCanvas3DManager::EMultisampleState GLCanvas3DManager::s_multisample = GLCanvas3DManager::MS_Unknown;
 bool GLCanvas3DManager::s_compressed_textures_supported = false;
-bool GLCanvas3DManager::s_framebuffers_supported = false;
+GLCanvas3DManager::EFramebufferType GLCanvas3DManager::s_framebuffers_type = GLCanvas3DManager::FB_None;
 GLCanvas3DManager::GLInfo GLCanvas3DManager::s_gl_info;
 
 GLCanvas3DManager::GLCanvas3DManager()
@@ -270,10 +270,12 @@ void GLCanvas3DManager::init_gl()
         else
             s_compressed_textures_supported = false;
 
-        if (s_gl_info.is_version_greater_or_equal_to(3, 0) && GLEW_ARB_framebuffer_object)
+        if (GLEW_ARB_framebuffer_object)
-            s_framebuffers_supported = true;
+            s_framebuffers_type = FB_Arb;
+        else if (GLEW_EXT_framebuffer_object)
+            s_framebuffers_type = FB_Ext;
         else
-            s_framebuffers_supported = false;
+            s_framebuffers_type = FB_None;
 
         if (! s_gl_info.is_version_greater_or_equal_to(2, 0)) {
         	// Complain about the OpenGL version.

src/slic3r/GUI/GLCanvas3DManager.hpp

@@ -30,6 +30,13 @@ struct Camera;
 class GLCanvas3DManager
 {
 public:
+    enum EFramebufferType : unsigned char
+    {
+        FB_None,
+        FB_Arb,
+        FB_Ext
+    };
+
     class GLInfo
     {
         mutable bool m_detected;
@@ -77,7 +84,7 @@ private:
     bool m_gl_initialized;
     static EMultisampleState s_multisample;
     static bool s_compressed_textures_supported;
-    static bool s_framebuffers_supported;
+    static EFramebufferType s_framebuffers_type;
 
 public:
     GLCanvas3DManager();
@@ -98,7 +105,8 @@ public:
 
     static bool can_multisample() { return s_multisample == MS_Enabled; }
     static bool are_compressed_textures_supported() { return s_compressed_textures_supported; }
-    static bool are_framebuffers_supported() { return s_framebuffers_supported; }
+    static bool are_framebuffers_supported() { return (s_framebuffers_type != FB_None); }
+    static EFramebufferType get_framebuffers_type() { return s_framebuffers_type; }
 
     static wxGLCanvas* create_wxglcanvas(wxWindow *parent);