Add initial wrapping code and example

examples/perf.nim

@@ -0,0 +1,123 @@
+import nanovg
+import strformat
+
+const GRAPH_HISTORY_COUNT = 100
+
+type
+  RenderStyle* {.pure.} = enum
+    FPS,
+    MS,
+    PERCENT
+
+  PerfGraph* = ref object
+    style: RenderStyle
+    name: string
+    values: array[GRAPH_HISTORY_COUNT, float]
+    head: int
+
+
+proc newGraph*(style: RenderStyle, name: string): PerfGraph =
+  new(result)
+  result.style = style
+  result.name = name
+
+proc update*(graph: PerfGraph, frameTime: float) =
+  graph.head = (graph.head + 1) mod GRAPH_HISTORY_COUNT
+  graph.values[graph.head] = frameTime
+
+proc getGraphAverage(graph: PerfGraph): float =
+  var avg: float = 0.0
+  for i in 0 ..< GRAPH_HISTORY_COUNT:
+    avg += graph.values[i]
+
+  return avg / GRAPH_HISTORY_COUNT.float
+
+proc render*(graph: PerfGraph, x, y: float) =
+  let
+    avg = getGraphAverage(graph)
+    width: float = 200
+    height: float = 35
+
+  nanovg.beginPath()
+  nanovg.pathRect(x, y, width, height)
+  nanovg.setFillColor(0, 0, 0, 128)
+  nanovg.pathFill()
+
+  nanovg.beginPath()
+  nanovg.pathMoveTo(x, y+height)
+
+  case graph.style:
+    of RenderStyle.FPS:
+      for i in 0 ..< GRAPH_HISTORY_COUNT:
+        var v: float = 1.0 / (0.00001 + graph.values[(graph.head+i) mod GRAPH_HISTORY_COUNT])
+        var vx, vy: float
+
+        if v > 80:
+          v = 80
+
+        vx = x + (i/(GRAPH_HISTORY_COUNT-1)) * width
+        vy = y + height - ((v / 80) * height)
+
+        nanovg.pathLineTo(vx, vy)
+
+    of RenderStyle.PERCENT:
+      for i in 0 ..< GRAPH_HISTORY_COUNT:
+        var v: float = graph.values[(graph.head+i) mod GRAPH_HISTORY_COUNT]
+        var vx, vy: float
+
+        if v > 100:
+          v = 100
+
+        vx = x + (i/(GRAPH_HISTORY_COUNT-1)) * width
+        vy = y + height - ((v / 100) * height)
+
+        nanovg.pathLineTo(vx, vy)
+
+    of RenderStyle.MS:
+      for i in 0 ..< GRAPH_HISTORY_COUNT:
+        var v: float = graph.values[(graph.head+i) mod GRAPH_HISTORY_COUNT] * 1000
+        var vx, vy: float
+
+        if v > 20:
+          v = 20
+
+        vx = x + (i/(GRAPH_HISTORY_COUNT-1)) * width
+        vy = y + height - ((v / 20) * height)
+
+        nanovg.pathLineTo(vx, vy)
+
+  nanovg.pathLineTo(x+width, y+height)
+  nanovg.setFillColor(255, 192, 0, 128)
+  nanovg.pathFill()
+
+  nanovg.setFont("sans")
+
+  if graph.name.len() > 0:
+    nanovg.setFontSize(14)
+    nanovg.textAlign("top left")
+    nanovg.setFillColor(240, 240, 240, 192)
+    nanovg.text(x+3, y+1, graph.name)
+
+  nanovg.setFontSize(18)
+  nanovg.textAlign("top right")
+  nanovg.setFillColor(240, 240, 240, 255)
+
+  case graph.style:
+    of RenderStyle.FPS:
+      var str = fmt"{1.0/avg:.2f} FPS"
+
+      nanovg.text(x+width-3, y+1, str)
+      nanovg.setFontSize(15)
+      nanovg.textAlign("bottom right")
+      nanovg.setFillColor(240, 240, 240, 160)
+
+      str = fmt"{avg*1000:.2f} ms"
+      nanovg.text(x+width-3, y+height-1, str)
+
+    of RenderStyle.PERCENT:
+      let str = fmt"{avg:.1f} %"
+      nanovg.text(x+width-3, y+1, str)
+
+    of RenderStyle.MS:
+      let str = fmt"{avg*1000:.2f} ms"
+      nanovg.text(x+width-3, y+1, str)