drawing a grid

blokus/blokus.go

@@ -1,10 +1,11 @@
-package blockus
+package blokus
 
 const BoardSize = 20
 
 // order of players
 const (
-	Blue = iota
+	Empty = iota
+	Blue
 	Yellow
 	Red
 	Green
@@ -91,3 +92,5 @@ var Tiles = [][][]bool{
 		{false, true, false},
 	},
 }
+
+var Board [BoardSize][BoardSize]int

main.go

@@ -3,21 +3,30 @@ package main
 import (
 	"sdl"
 	"fmt"
-	// TODO: why is the explicit name required?
-	blokus "blokus"
+	"blokus"
 )
 
 var running = true
+var screen *sdl.Surface
+
+var cellSize int
+var offsetX int
+var offsetY int
+
+const margin = 4
+const borderWidth = 1
+const boardStart = margin + borderWidth
+const gridSize = 2*margin + 2*borderWidth + blokus.BoardSize
+
+const emptyCellColor = 0x0
 
 func main() {
 	fmt.Println("loaded", len(blokus.Tiles), "shapes")
+	blokus.Board[2][4] = blokus.Red
 	if sdl.Init(sdl.INIT_EVERYTHING) != 0 {
 		panic(sdl.GetError())
 	}
-	var screen = sdl.SetVideoMode(640, 480, 32, sdl.RESIZABLE)
-	if screen == nil {
-		panic(sdl.GetError())
-	}
+	resize(640, 480)
 	sdl.WM_SetCaption("Blokus", "")
 
 	for running {
@@ -34,50 +43,97 @@ func main() {
 			case sdl.MOUSEBUTTONDOWN:
 				mouseDown(e.MouseButton())
 			case sdl.VIDEORESIZE:
-				screen = sdl.SetVideoMode(int(e.Resize().W), int(e.Resize().H), 32, sdl.RESIZABLE)
-				if screen == nil {
-					panic(sdl.GetError())
-				}
+				r := e.Resize()
+				resize(int(r.W), int(r.H))
 			default:
 			}
 			if !running {
 				break
 			}
 		}
 
-		draw(screen)
+		draw()
 
 		sdl.Delay(25)
 	}
 
 	sdl.Quit()
 }
+func resize(width int, height int) {
+	screen = sdl.SetVideoMode(width, height, 32, sdl.RESIZABLE)
+	if screen == nil {
+		panic(sdl.GetError())
+	}
+
+	gridSizePixels := min(width, height)
+	cellSize = gridSizePixels / gridSize
+	offsetX = (width - gridSizePixels) / 2
+	offsetY = (height - gridSizePixels) / 2
+}
+
+func min(a int, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
 
 func stop() {
 	running = false
 }
 
-func draw(screen *sdl.Surface) {
+func draw() {
 	screen.FillRect(nil, 0xa0a0a0)
+	drawBorder()
 	screen.Flip()
 }
 
+func drawBorder() {
+	for y := 0; y < blokus.BoardSize; y++ {
+		for x := 0; x < blokus.BoardSize; x++ {
+			var color uint32
+			switch blokus.Board[x][y] {
+			case blokus.Empty:
+				color = 0x0
+			case blokus.Blue:
+				color = 0x0000ff
+			case blokus.Yellow:
+				color = 0xffff00
+			case blokus.Red:
+				color = 0xff0000
+			case blokus.Green:
+				color = 0x00ff00
+			}
+			screen.FillRect(rect(pixelX(x)+1, pixelY(y)+1, cellSize-2, cellSize-2), color)
+		}
+	}
+}
+func pixelX(cellX int) int {
+	return offsetX + cellSize*(boardStart+cellX)
+}
+func pixelY(cellY int) int {
+	return offsetY + cellSize*(boardStart+cellY)
+}
+
+func rect(x int, y int, w int, h int) *sdl.Rect {
+	return &sdl.Rect{int16(x), int16(y), uint16(w), uint16(h)}
+}
+
 func keyUp(k *sdl.KeyboardEvent) {
-	debugKeyboardEvent(k)
+	//debugKeyboardEvent(k)
 }
 func keyDown(k *sdl.KeyboardEvent) {
-	debugKeyboardEvent(k)
+	//debugKeyboardEvent(k)
+	if k.Keysym.Sym == 27 {
+		stop()
+	}
 }
 func debugKeyboardEvent(k *sdl.KeyboardEvent) {
 	println("")
 	println(k.Keysym.Sym, ": ", sdl.GetKeyName(sdl.Key(k.Keysym.Sym)))
 
 	fmt.Printf("Type: %02x Which: %02x State: %02x Pad: %02x\n", k.Type, k.Which, k.State, k.Pad0[0])
 	fmt.Printf("Scancode: %02x Sym: %08x Mod: %04x Unicode: %04x\n", k.Keysym.Scancode, k.Keysym.Sym, k.Keysym.Mod, k.Keysym.Unicode)
-
-	if k.Keysym.Sym == 27 {
-		stop()
-	}
 }
 
 func mouseDown(mouseButton *sdl.MouseButtonEvent) {