From 84d4ca63c2e92407c30aee78a915f0978ec2ed39 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Sun, 29 May 2022 02:13:08 -0500
Subject: [PATCH] GUI: sample editor preview in selection

---
 TODO.md                 |  1 -
 src/engine/engine.cpp   |  6 ++++--
 src/engine/engine.h     |  7 +++++--
 src/engine/playback.cpp | 10 +++++-----
 src/gui/gui.cpp         | 15 ++++++++++++++-
 5 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/TODO.md b/TODO.md
index c8d7684a..bb039549 100644
--- a/TODO.md
+++ b/TODO.md
@@ -6,7 +6,6 @@
 - the last three compat flags
 - add OPL drum instrument type
 - Game Boy envelope macro/sequence
-- sample editor preview in selection
 - rewrite the system name detection function anyway
 - unified data view
 - volume commands should work on Game Boy
diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 14694415..812159e7 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -1471,8 +1471,10 @@ int DivEngine::getEffectiveSampleRate(int rate) {
   return rate;
 }
 
-void DivEngine::previewSample(int sample, int note) {
+void DivEngine::previewSample(int sample, int note, int pStart, int pEnd) {
   BUSY_BEGIN;
+  sPreview.pBegin=pStart;
+  sPreview.pEnd=pEnd;
   if (sample<0 || sample>=(int)song.sample.size()) {
     sPreview.sample=-1;
     sPreview.pos=0;
@@ -1488,7 +1490,7 @@ void DivEngine::previewSample(int sample, int note) {
   if (rate<100) rate=100;
   blip_set_rates(samp_bb,rate,got.rate);
   samp_prevSample=0;
-  sPreview.pos=0;
+  sPreview.pos=(sPreview.pBegin>=0)?sPreview.pBegin:0;
   sPreview.sample=sample;
   sPreview.wave=-1;
   BUSY_END;
diff --git a/src/engine/engine.h b/src/engine/engine.h
index ceb786a7..1ad8eb2e 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -339,10 +339,13 @@ class DivEngine {
     int sample;
     int wave;
     unsigned int pos;
+    int pBegin, pEnd;
     SamplePreview():
       sample(-1),
       wave(-1),
-      pos(0) {}
+      pos(0),
+      pBegin(-1),
+      pEnd(-1) {}
   } sPreview;
 
   short vibTable[64];
@@ -525,7 +528,7 @@ class DivEngine {
     void syncReset();
 
     // trigger sample preview
-    void previewSample(int sample, int note=-1);
+    void previewSample(int sample, int note=-1, int pStart=-1, int pEnd=-1);
     void stopSamplePreview();
 
     // trigger wave preview
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 3b11ab49..73e12238 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1159,7 +1159,7 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
       DivSample* s=song.sample[sPreview.sample];
 
       for (size_t i=0; i<prevtotal; i++) {
-        if (sPreview.pos>=s->samples) {
+        if (sPreview.pos>=s->samples || (sPreview.pEnd>=0 && (int)sPreview.pos>=sPreview.pEnd)) {
           samp_temp=0;
         } else {
           samp_temp=s->data16[sPreview.pos++];
@@ -1167,15 +1167,15 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
         blip_add_delta(samp_bb,i,samp_temp-samp_prevSample);
         samp_prevSample=samp_temp;
 
-        if (sPreview.pos>=s->samples) {
-          if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
+        if (sPreview.pos>=s->samples || (sPreview.pEnd>=0 && (int)sPreview.pos>=sPreview.pEnd)) {
+          if (s->loopStart>=0 && s->loopStart<(int)s->samples && (int)sPreview.pos>=s->loopStart) {
             sPreview.pos=s->loopStart;
           }
         }
       }
 
-      if (sPreview.pos>=s->samples) {
-        if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
+      if (sPreview.pos>=s->samples || (sPreview.pEnd>=0 && (int)sPreview.pos>=sPreview.pEnd)) {
+        if (s->loopStart>=0 && s->loopStart<(int)s->samples && (int)sPreview.pos>=s->loopStart) {
           sPreview.pos=s->loopStart;
         } else {
           sPreview.sample=-1;
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 2bf6888f..d4c56ded 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -2243,7 +2243,20 @@ int FurnaceGUI::processEvent(SDL_Event* ev) {
             int key=noteKeys.at(ev->key.keysym.scancode);
             int num=12*curOctave+key;
             if (key!=100 && key!=101 && key!=102) {
-              e->previewSample(curSample,num);
+              int pStart=-1;
+              int pEnd=-1;
+              if (curWindow==GUI_WINDOW_SAMPLE_EDIT) {
+                if (sampleSelStart!=sampleSelEnd) {
+                  pStart=sampleSelStart;
+                  pEnd=sampleSelEnd;
+                  if (pStart>pEnd) {
+                    pStart^=pEnd;
+                    pEnd^=pStart;
+                    pStart^=pEnd;
+                  }
+                }
+              }
+              e->previewSample(curSample,num,pStart,pEnd);
               samplePreviewOn=true;
               samplePreviewKey=ev->key.keysym.scancode;
               samplePreviewNote=num;