GUI: improve sample type conversion

src/engine/sample.cpp

@@ -699,6 +699,40 @@ bool DivSample::insert(unsigned int pos, unsigned int length) {
   return false;
 }
 
+void DivSample::convert(DivSampleDepth newDepth) {
+  render();
+  depth=newDepth;
+  switch (depth) {
+    case DIV_SAMPLE_DEPTH_1BIT:
+      setSampleCount((samples+7)&(~7));
+      break;
+    case DIV_SAMPLE_DEPTH_1BIT_DPCM:
+      setSampleCount((1+((((samples+7)/8)+15)&(~15)))<<3);
+      break;
+    case DIV_SAMPLE_DEPTH_YMZ_ADPCM:
+      setSampleCount(((lengthZ+3)&(~0x03))*2);
+      break;
+    case DIV_SAMPLE_DEPTH_QSOUND_ADPCM: // QSound ADPCM
+      setSampleCount((samples+1)&(~1));
+      break;
+    case DIV_SAMPLE_DEPTH_ADPCM_A: // ADPCM-A
+      setSampleCount((samples+1)&(~1));
+      break;
+    case DIV_SAMPLE_DEPTH_ADPCM_B: // ADPCM-B
+      setSampleCount((samples+1)&(~1));
+      break;
+    case DIV_SAMPLE_DEPTH_BRR: // BRR
+      setSampleCount(16*(lengthBRR/9));
+      break;
+    case DIV_SAMPLE_DEPTH_VOX: // VOX
+      setSampleCount((samples+1)&(~1));
+      break;
+    default:
+      break;
+  }
+  render();
+}
+
 #define RESAMPLE_BEGIN \
   if (samples<1) return true; \
   int finalCount=(double)samples*(tRate/sRate); \

src/engine/sample.h

@@ -269,6 +269,13 @@ struct DivSample {
    */
   bool resample(double sRate, double tRate, int filter);
 
+  /**
+   * convert sample depth.
+   * @warning do not attempt to do this outside of a synchronized block!
+   * @param newDepth the new depth.
+   */
+  void convert(DivSampleDepth newDepth);
+
   /**
    * initialize the rest of sample formats for this sample.
    */

src/gui/sampleEdit.cpp

@@ -257,8 +257,7 @@ void FurnaceGUI::drawSampleEdit() {
               if (ImGui::Selectable(sampleDepths[i])) {
                 sample->prepareUndo(true);
                 e->lockEngine([this,sample,i]() {
-                  sample->render();
-                  sample->depth=(DivSampleDepth)i;
+                  sample->convert((DivSampleDepth)i);
                   e->renderSamples();
                 });
                 updateSampleTex=true;