From e7a3bca3e3950a91072e5fbc2b5682738ca4c5d7 Mon Sep 17 00:00:00 2001
From: EriKWDev <ErikWDev@gmail.com>
Date: Tue, 6 Apr 2021 11:59:04 +0200
Subject: [PATCH] Fixes #3. Adds Entity Style. Begins work on #6

---
 src/nanim/core.nim          | 103 ++++++++++++++++++++++++++++++++----
 src/nanim/drawing.nim       |  63 +++++++++++++---------
 src/nanim/entities/text.nim |  11 ++--
 src/nanim/rendering.nim     |   2 +
 tests/nim.cfg               |   3 +-
 5 files changed, 138 insertions(+), 44 deletions(-)

diff --git a/src/nanim/core.nim b/src/nanim/core.nim
index dcdff17..fd80e16 100644
--- a/src/nanim/core.nim
+++ b/src/nanim/core.nim
@@ -17,11 +17,30 @@ type
   AngleMode* = enum
     amDegrees, amRadians
 
+  StyleMode* = enum
+    smSolidColor, smPaintPattern, smNone
+
+  Style* = ref tuple
+    fillMode: StyleMode
+    fillColor: Color
+    fillPattern: proc(context: NVGContext): Paint
+
+    strokeMode: StyleMode
+    strokeColor: Color
+    strokePattern: proc(context: NVGContext): Paint
+    strokeWidth: float
+
+    winding: PathWinding
+    lineCap: LineCapJoin
+    lineJoin: LineCapJoin
+    compositeOperation: CompositeOperation
+
   Entity* = ref object of RootObj
     points*: seq[Vec3[float]]
 
     tension*: float
     cornerRadius*: float
+    style*: Style
 
     position*: Vec3[float]
     rotation*: float
@@ -58,6 +77,62 @@ type
     done*: bool
 
 
+func newStyle*(): Style =
+  new(result)
+  result.fillMode = smPaintPattern
+  result.fillColor = rgb(255, 56, 116)
+  result.fillPattern = defaultPattern
+
+  result.strokeMode = smSolidColor
+  result.strokeColor = rgb(230, 26, 94)
+  result.strokePattern = defaultPattern
+  result.strokeWidth = 2.0
+
+  result.winding = pwCCW
+  result.lineCap = lcjRound
+  result.lineJoin = lcjMiter
+  result.compositeOperation = coSourceOver
+
+
+proc setStyle*(context: NVGContext, style: Style) =
+  case style.fillMode:
+  of smSolidColor:
+    context.fillColor(style.fillColor)
+  of smPaintPattern:
+    context.fillPaint(style.fillPattern(context))
+  of smNone: discard
+
+  context.strokeWidth(style.strokeWidth)
+  case style.strokeMode:
+  of smSolidColor:
+    context.strokeColor(style.strokeColor)
+  of smPaintPattern:
+    context.strokePaint(style.strokePattern(context))
+  of smNone: context.strokeWidth(0.0)
+
+  context.pathWinding(style.winding)
+  context.lineJoin(style.lineJoin)
+  context.lineCap(style.lineCap)
+  context.globalCompositeOperation(style.compositeOperation)
+
+
+proc executeStyle*(context: NVGContext, style: Style) =
+  case style.fillMode:
+  of smSolidColor, smPaintPattern:
+    context.fill()
+  of smNone: discard
+
+  case style.strokeMode:
+  of smSolidColor, smPaintPattern:
+    context.stroke()
+  of smNone: discard
+
+
+proc applyStyle*(context: NVGContext, style: Style) =
+  context.setStyle(style)
+  context.executeStyle(style)
+
+
 const
   defaultTrackId* = 0
   defaultAngleMode*: AngleMode = amDegrees
@@ -75,26 +150,22 @@ proc `$`*(entity: Entity): string =
 
 method draw*(entity: Entity, scene: Scene) {.base.} =
   let context = scene.context
-  context.beginPath()
+  context.save()
 
+  context.beginPath()
   if entity.tension > 0:
     context.drawPointsWithTension(entity.points, entity.tension)
   else:
     context.drawPointsWithRoundedCornerRadius(entity.points, entity.cornerRadius)
-
   context.closePath()
 
-  # context.fillColor(rgb(255, 56, 116))
-  context.fillPaint(context.gridPattern())
-  context.fill()
-
-  context.strokeColor(rgb(230, 26, 94))
-  context.strokeWidth(5)
-  context.stroke()
+  context.applyStyle(entity.style)
+  context.restore()
 
 
 func init*(entity: Entity) =
   entity.points = @[]
+  entity.style = newStyle()
   entity.children = @[]
   entity.tension = 0.0
   entity.cornerRadius = 20.0
@@ -343,6 +414,16 @@ proc setCornerRadius*(entity: Entity, cornerRadius: float = 0.0): Tween =
   result = newTween(interpolators)
 
 
+proc fill(context: NVGContext, width: cfloat, height: cfloat, color: Color = rgb(255, 255, 255)) =
+  context.save()
+  context.fillColor(color)
+  context.beginPath()
+  context.resetTransform()
+  context.rect(0, 0, width, height)
+  context.closePath()
+  context.fill()
+  context.restore()
+
 proc init(scene: Scene) =
   scene.time = 0.0
   scene.restartTime = 0.0
@@ -356,7 +437,9 @@ proc init(scene: Scene) =
                                           vec4[float](0,0,1,0),
                                           vec4[float](0,0,0,1))
   scene.done = false
-  scene.background = proc(scene: Scene) = clearWithColor(rgb(255, 255, 255))
+  scene.background =
+    proc(scene: Scene) = scene.context.fill(scene.width.cfloat, scene.height.cfloat, rgb(255, 255, 255))
+
   scene.foreground = proc(scene: Scene) = discard
 
 
diff --git a/src/nanim/drawing.nim b/src/nanim/drawing.nim
index 82fe60e..8ecb145 100644
--- a/src/nanim/drawing.nim
+++ b/src/nanim/drawing.nim
@@ -2,6 +2,7 @@
 import
   nanovg,
   opengl,
+  glfw,
   glm
 
 
@@ -57,9 +58,9 @@ proc drawPointsWithRoundedCornerRadius*(context: NVGContext, points: seq[Vec], c
     context.arcTo(p1.x, p1.y, midPoint.x, midPoint.y, cornerRadius)
 
 
-proc defaultPattern(context: NVGContext) =
+proc defaultPatternDrawer(context: NVGContext, width: float, height: float) =
   context.beginPath()
-  context.circle(5, 1440-5, 3)
+  context.circle(width/2, height/2, width/2)
   context.closePath()
 
   context.fillColor(rgb(20, 20, 20))
@@ -70,45 +71,57 @@ var
   patternPaint: Paint
   hasGatheredPattern = false
 
-proc gridPattern*(context: NVGContext, patternDrawer: proc(context: NVGContext) = defaultPattern, width: cint = 10, height: cint = 10): Paint =
+
+proc offset(some: pointer; b: int): pointer {.inline.} =
+  result = cast[pointer](cast[int](some) + b)
+
+
+proc gridPattern*(context: NVGContext, patternDrawer: proc(context: NVGContext, width: float, height: float) = defaultPatternDrawer, width: cint = 10, height: cint = 10): Paint =
   # Impure, but worth it for the performance benefit...
   if hasGatheredPattern:
     return patternPaint
 
   let
-    bufferSize = width*height*4
-    oldTransformMatrix = context.currentTransform()
+    bufferSize = width * height * 4
+    tempContext = nvgCreateContext({nifStencilStrokes, nifDebug})
 
-  var
-    oldData = alloc0(bufferSize)
-    imageData = alloc0(bufferSize)
+  var imageData = alloc0(bufferSize)
 
-  context.endFrame()
-
-  glPixelStorei(GL_PACK_ALIGNMENT, 1)
-  glReadBuffer(GL_BACK)
-
-  glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, oldData)
+  # clear the region
   glDrawPixels(width, height, GL_RGBA, GL_UNSIGNED_BYTE, imageData)
 
-  context.beginFrame(2880.cfloat, 1440.cfloat, 1)
-  patternDrawer(context)
-  context.endFrame()
+  # draw the pattern
+  let
+    window = currentContext()
+    (frameBufferWidth, frameBufferHeight) = window.framebufferSize
+
+  tempContext.beginFrame(frameBufferWidth.cfloat, frameBufferHeight.cfloat, 1)
+  clearWithColor()
+  tempContext.translate(0, frameBufferHeight.float - height.float)
+  patternDrawer(tempContext, width.float, height.float)
+  tempContext.endFrame()
 
+  # read the region
   glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, imageData)
-  var pixels: seq[uint8] = newSeq[uint8](bufferSize)
-  copyMem(pixels[0].unsafeAddr, imageData, bufferSize)
+
+  var pixels = newSeq[uint8](bufferSize)
+
+  # Flip the image
+  for y in 0..<height:
+    let
+      lineSize = width * 4
+      yDest = y * lineSize
+      ySrc = bufferSize - yDest - lineSize
+    copyMem(pixels[yDest].unsafeAddr, imageData.offset(ySrc), lineSize)
+
   let image = context.createImageRGBA(width, height, {ifRepeatX, ifRepeatY, ifFlipY}, pixels)
 
   patternPaint = context.imagePattern(0, 0, width.cfloat, height.cfloat, 0, image, 1.0)
   hasGatheredPattern = true
   result = patternPaint
 
-  context.beginFrame(2880.cfloat, 1440.cfloat, 1)
-  glDrawPixels(width, height, GL_RGBA, GL_UNSIGNED_BYTE, oldData)
-
-  dealloc(oldData)
   dealloc(imageData)
 
-  context.transform(oldTransformMatrix.m[0], oldTransformMatrix.m[1], oldTransformMatrix.m[2],
-                    oldTransformMatrix.m[3], oldTransformMatrix.m[4], oldTransformMatrix.m[5])
+
+proc defaultPattern*(context: NVGContext): Paint =
+  context.gridPattern(defaultPatternDrawer, 10, 10)
diff --git a/src/nanim/entities/text.nim b/src/nanim/entities/text.nim
index 4664164..3f2f0d6 100644
--- a/src/nanim/entities/text.nim
+++ b/src/nanim/entities/text.nim
@@ -16,6 +16,7 @@ type
 proc init*(text: Text) =
   init(text.Entity)
   text.message = ""
+  text.style.fillMode = smSolidColor
 
 
 method draw*(text: Text, scene: Scene) =
@@ -24,17 +25,11 @@ method draw*(text: Text, scene: Scene) =
   context.fontSize(text.fontSize * 10)
   context.fontFace(text.font)
 
-  context.beginPath()
-
-  context.fillColor(rgb(255, 56, 116))
-
-  context.strokeColor(rgb(230, 26, 94))
-  context.strokeWidth(20)
+  context.setStyle(text.style)
 
+  context.beginPath()
   discard context.text(0, 0, text.message)
   context.closePath()
-  context.stroke()
-  context.fill()
 
 
 proc newText*(message: string = "",
diff --git a/src/nanim/rendering.nim b/src/nanim/rendering.nim
index 4e49ad6..6473305 100644
--- a/src/nanim/rendering.nim
+++ b/src/nanim/rendering.nim
@@ -59,6 +59,8 @@ proc setupRendering(userScene: Scene, resizable: bool = true, width: int = 1920,
   doAssert glInit()
 
   glEnable(GL_MULTISAMPLE)
+  glEnable(GL_BLEND)
+  # glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
 
   makeContextCurrent(scene.window)
 
diff --git a/tests/nim.cfg b/tests/nim.cfg
index ac5825b..da671db 100644
--- a/tests/nim.cfg
+++ b/tests/nim.cfg
@@ -1 +1,2 @@
---path:"../src/"
\ No newline at end of file
+--path:"../src/"
+-d:glfwStaticLib
\ No newline at end of file