FIx 0 acceleration for reprap

#4048

src/libslic3r/GCodeWriter.cpp

@@ -311,23 +311,34 @@ std::string GCodeWriter::write_acceleration(){
 	//try to set only printing acceleration, travel should be untouched if possible
     if (FLAVOR_IS(gcfRepetier)) {
         // M201: Set max printing acceleration
-        gcode << "M201 X" << m_current_acceleration << " Y" << m_current_acceleration;
+        if (m_current_acceleration > 0)
+            gcode << "M201 X" << m_current_acceleration << " Y" << m_current_acceleration;
     } else if(FLAVOR_IS(gcfLerdge) || FLAVOR_IS(gcfSprinter)){
         // M204: Set printing acceleration
         // This is new MarlinFirmware with separated print/retraction/travel acceleration.
         // Use M204 P, we don't want to override travel acc by M204 S (which is deprecated anyway).
-        gcode << "M204 P" << m_current_acceleration;
+        if (m_current_acceleration > 0)
+            gcode << "M204 P" << m_current_acceleration;
     } else if (FLAVOR_IS(gcfMarlinFirmware) || FLAVOR_IS(gcfRepRap)) {
         // M204: Set printing & travel acceleration
-        gcode << "M204 P" << m_current_acceleration << " T" << (m_current_travel_acceleration > 0 ? m_current_travel_acceleration : m_current_acceleration);
+        if (m_current_acceleration > 0)
+            gcode << "M204 P" << m_current_acceleration << " T" << (m_current_travel_acceleration > 0 ? m_current_travel_acceleration : m_current_acceleration);
+        else if(m_current_travel_acceleration > 0)
+            gcode << "M204 T" << m_current_travel_acceleration;
     } else { // gcfMarlinLegacy
         // M204: Set default acceleration
-        gcode << "M204 S" << m_current_acceleration;
+        if (m_current_acceleration > 0)
+            gcode << "M204 S" << m_current_acceleration;
     }
-    if (this->config.gcode_comments) gcode << " ; adjust acceleration";
-    gcode << "\n";
-
-    return gcode.str();
+    //if at least something, add comment and line return
+    if (gcode.tellp() != std::streampos(0)) {
+        if (this->config.gcode_comments)
+            gcode << " ; adjust acceleration";
+        gcode << "\n";
+        return gcode.str();
+    }
+    assert(gcode.str().empty());
+    return "";
 }
 
 std::string GCodeWriter::reset_e(bool force)

src/libslic3r/GCodeWriter.hpp

@@ -17,13 +17,7 @@ class GCodeWriter {
     // override from region
     const PrintRegionConfig* config_region = nullptr;
 
-    GCodeWriter() : 
-        multiple_extruders(false), m_extrusion_axis("E"), m_tool(nullptr),
-        m_single_extruder_multi_material(false),
-        m_last_acceleration(0), m_current_acceleration(0), m_current_speed(0),
-        m_last_bed_temperature(0), m_last_bed_temperature_reached(true), 
-        m_lifted(0)
-        {}
+    GCodeWriter() {}
     Tool*               tool()             { return m_tool; }
     const Tool*         tool()     const   { return m_tool; }
 
@@ -96,25 +90,25 @@ class GCodeWriter {
 	// Extruders are sorted by their ID, so that binary search is possible.
     std::vector<Extruder> m_extruders;
     std::vector<Mill> m_millers;
-    std::string     m_extrusion_axis;
-    bool            m_single_extruder_multi_material;
-    Tool*           m_tool;
-    uint32_t        m_last_acceleration;
-    uint32_t        m_last_travel_acceleration;
-    uint32_t        m_current_acceleration;
-    uint32_t        m_current_travel_acceleration;
-    double          m_current_speed;
-    uint8_t         m_last_fan_speed;
-    int16_t         m_last_temperature;
-    int16_t         m_last_temperature_with_offset;
-    int16_t         m_last_bed_temperature;
-    bool            m_last_bed_temperature_reached;
+    std::string     m_extrusion_axis = "E";
+    bool            m_single_extruder_multi_material = false;
+    Tool*           m_tool = nullptr;
+    uint32_t        m_last_acceleration = 0;
+    uint32_t        m_last_travel_acceleration = 0;
+    uint32_t        m_current_acceleration = 0;
+    uint32_t        m_current_travel_acceleration = 0;
+    double          m_current_speed = 0;
+    uint8_t         m_last_fan_speed = 0;
+    int16_t         m_last_temperature = 0;
+    int16_t         m_last_temperature_with_offset = 0;
+    int16_t         m_last_bed_temperature = 0;
+    bool            m_last_bed_temperature_reached = true;
     // if positive, it's set, and the next lift wil have this extra lift
     double          m_extra_lift = 0;
     // current lift, to remove from m_pos to have the current height.
-    double          m_lifted;
+    double          m_lifted = 0;
     Vec3d           m_pos = Vec3d::Zero();
-
+    
     std::string _travel_to_z(double z, const std::string &comment);
     std::string _retract(double length, std::optional<double> restart_extra, std::optional<double> restart_extra_toolchange, const std::string &comment);