Implement better pushContext()/popContext()

header.lua

@@ -1,7 +1,7 @@
 !if LOVE2D then
 require("playbit.graphics")
 
---[[ since there is no CoreLibs/playdate, this file should always 
+--[[ since there is no CoreLibs/playdate, this file should always
 be included here so the methods are always available ]]--
 require("playdate.playdate")
 --[[ not really a way around including this one, but probably doesn't really
@@ -35,6 +35,8 @@ math.randomseed(os.time())
 local font = playdate.graphics.font.new("fonts/Phozon/Phozon")
 playdate.graphics.setFont(font)
 
+local updateCoroutine
+
 function love.draw()
   -- must be changed at start of frame when canvas is not active
   local newCanvasWidth, newCanvasHeight = playbit.graphics.getCanvasSize()
@@ -66,9 +68,8 @@ function love.draw()
 
   -- render to canvas to allow 2x scaling
   love.graphics.setCanvas(playbit.graphics.canvas)
-  love.graphics.setShader(playbit.graphics.shader)
 
-  --[[ 
+  --[[
     Love2d won't allow a canvas to be set outside of the draw function, so we need to do this on the first frame of draw.
     Otherwise setting the bg color outside of playdate.update() won't be consistent with PD.
   --]]
@@ -86,7 +87,14 @@ function love.draw()
   love.graphics.translate(playbit.graphics.drawOffset.x, playbit.graphics.drawOffset.y)
 
   -- main update
-  playdate.update()
+  if not updateCoroutine or coroutine.status(updateCoroutine) == "dead" then
+    updateCoroutine = coroutine.create(playdate.update)
+  end
+
+  local ok, err = coroutine.resume(updateCoroutine)
+  if not ok then
+    error(err)
+  end
 
   -- debug draw
   if playdate.debugDraw then
@@ -102,19 +110,16 @@ function love.draw()
   love.graphics.setCanvas()
 
   -- clear shader so that canvas is rendered normally
-  love.graphics.setShader()
-
-  -- always render pure white so its not tinted
-  local r, g, b = love.graphics.getColor()
-  love.graphics.setColor(1, 1, 1, 1)
+  local shader = love.graphics.getShader()
+  love.graphics.setShader(playbit.graphics.shaders.final)
 
   -- draw canvas to screen
   local currentCanvasScale = playbit.graphics.getCanvasScale()
   local x, y = playbit.graphics.getCanvasPosition()
   love.graphics.draw(playbit.graphics.canvas, x, y, 0, currentCanvasScale, currentCanvasScale)
 
-  -- reset back to set color
-  love.graphics.setColor(r, g, b, 1)
+  -- reset back the shader
+  love.graphics.setShader(shader)
 
   -- update emulated input
   playdate.updateInput()

playbit/graphics.lua

@@ -10,20 +10,37 @@ module.COLOR_BLACK = { 49 / 255, 47 / 255, 40 / 255, 1 }
 
 module.colorWhite = module.COLOR_WHITE
 module.colorBlack = module.COLOR_BLACK
+
+module.shaders =
+{
+  final   = love.graphics.newShader("playbit/shaders/final.glsl"),
+  color   = love.graphics.newShader("playbit/shaders/color.glsl"),
+  pattern = love.graphics.newShader("playbit/shaders/pattern.glsl"),
+  image   = { }
+}
+
+local shader = love.filesystem.read("playbit/shaders/image.glsl")
+for i = 0, 9 do
+  local src = "#define DRAW_MODE " .. i .. "\n" .. shader
+  module.shaders.image[i] = love.graphics.newShader(src)
+end
+
 module.shader = love.graphics.newShader("playdate/shader")
 module.drawOffset = { x = 0, y = 0}
 module.drawColorIndex = 1
 module.drawColor = module.colorWhite
 module.backgroundColorIndex = 0
 module.backgroundColor = module.colorBlack
 module.activeFont = {}
-module.drawMode = "copy"
+module.imageDrawMode = 0
+module.drawMode = nil
 module.canvas = love.graphics.newCanvas()
 module.contextStack = {}
 -- shared quad to reduce gc
 module.quad = love.graphics.newQuad(0, 0, 1, 1, 1, 1)
 module.lastClearColor = module.colorWhite
-module.drawPattern = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
+module.drawPattern = nil
+module.lineWidth = 1
 
 local canvasScale = 1
 local canvasWidth = 400
@@ -107,44 +124,33 @@ end
 ---@param white table An array of 4 values that correspond to RGBA that range from 0 to 1.
 ---@param black table An array of 4 values that correspond to RGBA that range from 0 to 1.
 function module.setColors(white, black)
-  if white == nil then
-    white = module.COLOR_WHITE
-  end
-  if black == nil then
-    black = module.COLOR_BLACK
-  end
-
-  module.colorWhite = white
-  module.colorBlack = black
-  module.shader:send("white", white)
-  module.shader:send("black", black)
-
-  if module.backgroundColorIndex == 1 then
-    module.backgroundColor = module.colorWhite
-  else
-    module.backgroundColor = module.colorBlack
-  end
-
-  if module.drawColorIndex == 1 then
-    module.drawColor = module.colorWhite
-  else
-    module.drawColor = module.colorBlack
-  end
+  module.colorWhite = white or module.COLOR_WHITE
+  module.colorBlack = black or module.COLOR_BLACK
+  module.shaders.final:send("white", white)
+  module.shaders.final:send("black", black)
 end
 
-function module.updateContext()
-  if #module.contextStack == 0 then
-    return
-  end
+local function getShader(mode)
+  if mode == "line" then
+    return module.shaders.color
 
-  local activeContext = module.contextStack[#module.contextStack]
+  elseif mode == "fill" then
+    if module.drawPattern then
+      return module.shaders.pattern
+    else
+      return module.shaders.color
+    end
 
-  -- love2d doesn't allow calling newImageData() when canvas is active
-  love.graphics.setCanvas()
-  local imageData = activeContext._canvas:newImageData()
-  love.graphics.setCanvas(activeContext._canvas)
+  elseif mode == "image" then
+    return module.shaders.image[module.imageDrawMode]
+  end
+end
 
-  -- update image
-  activeContext.data:replacePixels(imageData)
+function module.setDrawMode(mode)
+  if module.drawMode ~= mode then
+    module.drawMode = mode
+    local shader = getShader(mode)
+    love.graphics.setShader(shader)
+  end
 end
-!end
+!end

playbit/shaders/color.glsl

@@ -0,0 +1,11 @@
+#pragma language glsl3
+
+extern vec4 drawColor;
+
+vec4 effect(vec4 color, Image tex, vec2 tex_coords, vec2 screen_coords)
+{
+    float outColor = drawColor.r;
+    float outAlpha = drawColor.a;
+
+    return vec4(outColor, outColor, outColor, outAlpha);
+}

playbit/shaders/final.glsl

@@ -0,0 +1,15 @@
+#pragma language glsl3
+
+extern vec4 white = vec4(176.0f / 255.0f, 174.0f / 255.0f, 167.0f / 255.0f, 1);
+extern vec4 black = vec4( 49.0f / 255.0f,  47.0f / 255.0f,  40.0f / 255.0f, 1);
+
+vec4 effect(vec4 color, Image tex, vec2 tex_coords, vec2 screen_coords)
+{
+    vec4 inColor = Texel(tex, tex_coords) * color;
+
+    vec4 outColor;
+    outColor.rgb = mix(black.rgb, white.rgb, inColor.r);
+    outColor.a   = 1;
+
+    return outColor;
+}

playbit/shaders/image.glsl

@@ -0,0 +1,49 @@
+#pragma language glsl3
+
+extern Image canvas;
+
+vec4 effect(vec4 color, Image tex, vec2 tex_coords, vec2 screen_coords)
+{
+    vec4  texColor   = Texel(tex, tex_coords);
+    float grayscale  = dot(texColor.rgb, vec3(0.2126, 0.7152, 0.0722));
+    float inColor    = step(0.5, grayscale);
+    float inAlpha    = step(0.5, texColor.a);
+
+#if DRAW_MODE == 1   // White Transparent
+    float outColor   = inColor;
+    float outAlpha   = inAlpha * (1.0 - inColor);
+
+#elif DRAW_MODE == 2 // Black Transparent
+    float outColor   = inColor;
+    float outAlpha   = inAlpha * inColor;
+
+#elif DRAW_MODE == 3 // Fill White
+    float outColor   = 1;
+    float outAlpha   = inAlpha;
+
+#elif DRAW_MODE == 4 // Fill Black
+    float outColor   = 0;
+    float outAlpha   = inAlpha;
+
+#elif DRAW_MODE == 5 // XOR
+    vec4 canvasColor = Texel(canvas, screen_coords / love_ScreenSize.xy);
+    float outColor   = abs(canvasColor.r - inColor);
+    float outAlpha   = inAlpha;
+
+#elif DRAW_MODE == 6 // NXOR
+    vec4 canvasColor = Texel(canvas, screen_coords / love_ScreenSize.xy);
+    float outColor   = 1.0 - abs(canvasColor.r - inColor);
+    float outAlpha   = inAlpha;
+
+#elif DRAW_MODE == 7 // Inverted
+    float outColor   = 1.0 - inColor;
+    float outAlpha   = inAlpha;
+
+#else                // Copy
+    float outColor   = inColor;
+    float outAlpha   = inAlpha;
+
+#endif
+
+    return vec4(outColor, outColor, outColor,  outAlpha);
+}

playbit/shaders/pattern.glsl

@@ -0,0 +1,15 @@
+#pragma language glsl3
+
+extern float pattern[64];
+
+vec4 effect(vec4 color, Image tex, vec2 tex_coords, vec2 screen_coords)
+{
+    // Use mod() to get the position of the current pixel within the 8x8 pattern
+    int x = int(mod(screen_coords.x, 8.0));
+    int y = int(mod(screen_coords.y, 8.0));
+
+    float outColor = pattern[x + y * 8];
+    float outAlpha = 1;
+
+    return vec4(outColor, outColor, outColor, outAlpha);
+}

playbit/util.lua

@@ -23,4 +23,24 @@ function module.sign(a)
   else
     return 0
   end
+end
+
+function module.clamp01(x)
+  if x <= 0 then
+    return 0
+  elseif x >= 1 then
+    return 1
+  else
+    return x
+  end
+end
+
+function module.clamp(x, min, max)
+  if x <= min then
+    return min
+  elseif x >= max then
+    return max
+  else
+    return x
+  end
 end