Tank fixes (#892)

* fixing turnration computation

* updated tank computation

* fix rendering glitch

* restore tank computation

* rounding errors

docs/reference/motors/synced/steer.md

@@ -86,6 +86,51 @@ for (let i = 0; i < 4; i++) {
 motors.stopAll()
 ```
 
+### Steer tester
+
+This program lets you change the values of speed and turn ratio with the buttons.
+
+```typescript
+let speed = 0;
+let turnRatio = 0;
+
+brick.showString(`steer tester`, 1)
+brick.showString(`connect motors BC`, 7)
+brick.showString(`up/down for speed`, 8)
+brick.showString(`left/right for turn ratio`, 9)
+
+forever(function () {
+    brick.showString(`motor B speed ${motors.largeB.speed()}%`, 4)
+    brick.showString(`motor C speed ${motors.largeC.speed()}%`, 5)
+    pause(100)
+})
+
+function updateSteer() {
+    motors.largeBC.steer(turnRatio, speed);
+    brick.showString(`speed ${speed}%`, 2)
+    brick.showString(`turnRatio ${turnRatio}`, 3)
+}
+
+brick.buttonUp.onEvent(ButtonEvent.Pressed, function () {
+    speed += 10
+    updateSteer()
+})
+brick.buttonDown.onEvent(ButtonEvent.Pressed, function () {
+    speed -= 10
+    updateSteer()
+})
+brick.buttonLeft.onEvent(ButtonEvent.Pressed, function () {
+    turnRatio -= 10
+    updateSteer()
+})
+brick.buttonRight.onEvent(ButtonEvent.Pressed, function () {
+    turnRatio += 10
+    updateSteer()
+})
+
+updateSteer()
+```
+
 ## See also
 
 [tank](/reference/motors/synced/tank), [run](/reference/motors/motor/run)

docs/reference/motors/synced/tank.md

@@ -82,6 +82,51 @@ pause(5000)
 motors.stopAll()
 ```
 
+### Tank tester
+
+This program lets you change the tank values using the brick buttons
+
+```typescript
+let tankB = 0;
+let tankC = 0;
+
+brick.showString(`tank tester`, 1)
+brick.showString(`connect motors BC`, 7)
+brick.showString(`up/down for tank B`, 8)
+brick.showString(`left/right for tank C`, 9)
+
+forever(function () {
+    brick.showString(`motor B speed ${motors.largeB.speed()}%`, 4)
+    brick.showString(`motor C speed ${motors.largeC.speed()}%`, 5)
+    pause(100)
+})
+
+function updateTank() {
+    brick.showString(`tank A: ${tankB}%`, 2)
+    brick.showString(`tank B: ${tankC}%`, 3)
+    motors.largeBC.tank(tankB, tankC);
+}
+
+brick.buttonUp.onEvent(ButtonEvent.Pressed, function () {
+    tankB += 10
+    updateTank();
+})
+brick.buttonDown.onEvent(ButtonEvent.Pressed, function () {
+    tankB -= 10
+    updateTank();
+})
+brick.buttonRight.onEvent(ButtonEvent.Pressed, function () {
+    tankC += 10
+    updateTank();
+})
+brick.buttonLeft.onEvent(ButtonEvent.Pressed, function () {
+    tankC -= 10
+    updateTank();
+})
+
+updateTank();
+```
+
 ## See also
 
 [steer](/reference/motors/synced/steer), [run](/reference/motors/motor/run)