draw basic field over player when player is attacking

shell/gl-draw.sml

@@ -8,6 +8,9 @@ struct
     , playerVertexBuffer: Word32.word
     , playerProgram: Word32.word
     , playerLength: int
+    , fieldVertexBuffer: Word32.word
+    , fieldProgram: Word32.word
+    , fieldLength: int
     }
 
   fun createShader (shaderType, shaderString) =
@@ -38,12 +41,21 @@ struct
       val rgbFragmentShader = createShader
         (Gles3.FRAGMENT_SHADER, GlShaders.rgbFragmentShaderString)
 
+      val xyrgbaVertexShader = createShader
+        (Gles3.VERTEX_SHADER, GlShaders.xyrgbaVertexShaderString)
+
+      val rgbaFragmentShader = createShader
+        (Gles3.FRAGMENT_SHADER, GlShaders.rgbaFragmentShaderString)
+
       (* wall here includes both walls and platforms *)
       val wallVertexBuffer = Gles3.createBuffer ()
       val wallProgram = createProgram (xyrgbVertexShader, rgbFragmentShader)
 
       val playerVertexBuffer = Gles3.createBuffer ()
       val playerProgram = createProgram (xyrgbVertexShader, rgbFragmentShader)
+
+      val fieldVertexBuffer = Gles3.createBuffer ()
+      val fieldProgram = createProgram (xyrgbaVertexShader, rgbaFragmentShader)
     in
       { window = window
       , wallVertexBuffer = wallVertexBuffer
@@ -52,6 +64,9 @@ struct
       , playerVertexBuffer = playerVertexBuffer
       , playerProgram = playerProgram
       , playerLength = 0
+      , fieldVertexBuffer = fieldVertexBuffer
+      , fieldProgram = fieldProgram
+      , fieldLength = 0
       }
     end
 
@@ -62,6 +77,9 @@ struct
         , playerVertexBuffer
         , playerProgram
         , playerLength
+        , fieldVertexBuffer
+        , fieldProgram
+        , fieldLength
         , wallVertexBuffer
         , wallProgram
         , wallLength = _
@@ -75,6 +93,9 @@ struct
       , playerVertexBuffer = playerVertexBuffer
       , playerProgram = playerProgram
       , playerLength = playerLength
+      , fieldVertexBuffer = fieldVertexBuffer
+      , fieldProgram = fieldProgram
+      , fieldLength = fieldLength
       , wallVertexBuffer = wallVertexBuffer
       , wallProgram = wallProgram
       , wallLength = newWallLength
@@ -88,6 +109,9 @@ struct
         , wallVertexBuffer
         , wallProgram
         , wallLength
+        , fieldVertexBuffer
+        , fieldProgram
+        , fieldLength
         , playerVertexBuffer
         , playerProgram
         , playerLength = _
@@ -101,12 +125,47 @@ struct
       , wallVertexBuffer = wallVertexBuffer
       , wallProgram = wallProgram
       , wallLength = wallLength
+      , fieldVertexBuffer = fieldVertexBuffer
+      , fieldProgram = fieldProgram
+      , fieldLength = fieldLength
       , playerVertexBuffer = playerVertexBuffer
       , playerProgram = playerProgram
       , playerLength = newPlayerLength
       }
     end
 
+  fun uploadField (shellState: t, vec) =
+    let
+      val
+        { window
+        , wallVertexBuffer
+        , wallProgram
+        , wallLength
+        , playerVertexBuffer
+        , playerProgram
+        , playerLength
+        , fieldVertexBuffer
+        , fieldProgram
+        , fieldLength = _
+        } = shellState
+
+      val _ = Gles3.bindBuffer fieldVertexBuffer
+      val _ = Gles3.bufferData (vec, Vector.length vec, Gles3.STATIC_DRAW)
+      val newFieldLength = Vector.length vec div 6
+    in
+      { window = window
+      , wallVertexBuffer = wallVertexBuffer
+      , wallProgram = wallProgram
+      , wallLength = wallLength
+      , playerVertexBuffer = playerVertexBuffer
+      , playerProgram = playerProgram
+      , playerLength = playerLength
+      , fieldVertexBuffer = fieldVertexBuffer
+      , fieldProgram = fieldProgram
+      , fieldLength = newFieldLength
+      }
+    end
+
   fun drawXyrgb (vertexBuffer, program, drawLength) =
     if drawLength > 0 then
       let
@@ -126,16 +185,39 @@ struct
     else
       ()
 
+  fun drawXyrgba (vertexBuffer, program, drawLength) =
+    if drawLength > 0 then
+      let
+        val _ = Gles3.bindBuffer vertexBuffer
+        (* enable xy component from uploaded array *)
+        val _ = Gles3.vertexAttribPointer (0, 2, 6, 0)
+        val _ = Gles3.enableVertexAttribArray 0
+        (* enable rgb component from uploaded array *)
+        val _ = Gles3.vertexAttribPointer (1, 4, 6, 8)
+        val _ = Gles3.enableVertexAttribArray 1
+
+        val _ = Gles3.useProgram program
+        val _ = Gles3.drawArrays (Gles3.TRIANGLES, 0, drawLength)
+      in
+        ()
+      end
+    else
+      ()
+
   fun drawWall ({wallVertexBuffer, wallProgram, wallLength, ...}: t) =
     drawXyrgb (wallVertexBuffer, wallProgram, wallLength)
 
   fun drawPlayer ({playerVertexBuffer, playerProgram, playerLength, ...}: t) =
     drawXyrgb (playerVertexBuffer, playerProgram, playerLength)
 
+  fun drawField ({fieldVertexBuffer, fieldProgram, fieldLength, ...}) =
+    drawXyrgba (fieldVertexBuffer, fieldProgram, fieldLength)
+
   fun draw (shellState: t) =
     let
       val _ = drawWall shellState
       val _ = drawPlayer shellState
+      val _ = drawField shellState
     in
       ()
     end
@@ -147,12 +229,6 @@ struct
           val _ = Gles3.clearColor (1.0, 1.0, 1.0, 1.0)
           val _ = Gles3.clear ()
 
-          (* todo:
-           * - update game state
-           * - consume draw messages 
-           * - finally, draw 
-           * *)
-
           val input = InputState.getSnapshot ()
           val width = InputState.getWidth ()
           val height = InputState.getHeight ()
@@ -167,8 +243,11 @@ struct
           val platVec = Platform.getDrawVec (#platforms game, width, height)
           val wallVec = Vector.concat [wallVec, platVec]
 
+          val fieldVec = Player.getFieldVec (#player game, width, height)
+
           val shellState = uploadWall (shellState, wallVec)
           val shellState = uploadPlayer (shellState, playerVec)
+          val shellState = uploadField (shellState, fieldVec)
 
           val _ = draw shellState