replay now allows seek to frame 0

src/common/recorder.ts

@@ -85,6 +85,10 @@ export class StateRecorderImpl implements EmuRecorder {
     }
 
     getStateAtOrBefore(frame : number) : {frame : number, state : EmuState} {
+        // initial frame?
+        if (frame <= 0 && this.checkpoints.length > 0)
+          return {frame:0, state:this.checkpoints[0]};
+
         var bufidx = Math.floor(frame / this.checkpointInterval);
         var foundidx = bufidx < this.checkpoints.length ? bufidx : this.checkpoints.length-1;
         var foundframe = foundidx * this.checkpointInterval;
@@ -111,6 +115,11 @@ export class StateRecorderImpl implements EmuRecorder {
                 frame++;
                 numSteps = this.platform.advance(frame < seekframe); // TODO: infinite loop?
             }
+            // TODO: if first frame, we must figure out # of steps
+            if (frame == 0) {
+              numSteps = this.platform.advance(true);
+              this.platform.loadState(state);
+            }
             // seek to step index
             // TODO: what if advance() returns clocks, but steps use insns?
             if (seekstep > 0 && this.platform.advanceFrameClock) { 
@@ -122,7 +131,7 @@ export class StateRecorderImpl implements EmuRecorder {
             this.lastStepCount = numSteps;
             return seekframe;
         } else {
-            return 0;
+            return -1;
         }
     }
     

src/ide/ui.ts

@@ -1638,7 +1638,7 @@ function setupReplaySlider() {
       _pause();
       var frame : number = parseInt(replayslider.val().toString());
       var step : number = parseInt(clockslider.val().toString());
-      if (stateRecorder.loadFrame(frame, step)) {
+      if (stateRecorder.loadFrame(frame, step) >= 0) {
         clockslider.attr('min', 0);
         clockslider.attr('max', stateRecorder.lastStepCount);
         updateFrameNo();
@@ -1647,7 +1647,7 @@ function setupReplaySlider() {
     };
     var setFrameTo = (frame:number) => {
       _pause();
-      if (stateRecorder.loadFrame(frame)) {
+      if (stateRecorder.loadFrame(frame) >= 0) {
         replayslider.val(frame);
         updateFrameNo();
         uiDebugCallback(platform.saveState());
@@ -1656,14 +1656,14 @@ function setupReplaySlider() {
     var setClockTo = (clock:number) => {
       _pause();
       var frame : number = parseInt(replayslider.val().toString());
-      if (stateRecorder.loadFrame(frame, clock)) {
+      if (stateRecorder.loadFrame(frame, clock) >= 0) {
         clockslider.val(clock);
         updateFrameNo();
         uiDebugCallback(platform.saveState());
       }
     };
     stateRecorder.callbackStateChanged = () => {
-      replayslider.attr('min', 1);
+      replayslider.attr('min', 0);
       replayslider.attr('max', stateRecorder.numFrames());
       replayslider.val(stateRecorder.currentFrame());
       clockslider.val(stateRecorder.currentStep());

test/cli/testplatforms.js

@@ -157,6 +157,7 @@ async function testPlatform(platid, romname, maxframes, callback) {
     var state1 = platform.saveState();
     platform.loadState(state1);
     assert.deepEqual(state1, platform.saveState());
+    assert.equal(0, rec.loadFrame(0));
     assert.equal(1, rec.loadFrame(1));
     assert.equal(maxframes, rec.loadFrame(maxframes));
     var state2 = platform.saveState();