Refactoring

graphics/graphics.go

@@ -1,5 +1,9 @@
 package graphics
 
+import (
+	"image/color"
+)
+
 type Rect struct {
 	X      int
 	Y      int
@@ -13,6 +17,12 @@ type TexturePart struct {
 	Source    Rect
 }
 
+type Line struct {
+	X1, Y1 int
+	X2, Y2 int
+	Color color.Color
+}
+
 type TextureId int
 
 // A render target is essentially same as a texture, but it is assumed that the

graphics/opengl/canvas.go

@@ -38,14 +38,16 @@ func newCanvas(ids *ids, screenWidth, screenHeight, screenScale int) *Canvas {
 }
 
 func (canvas *Canvas) update(draw func(graphics.Canvas)) {
-	canvas.init()
+	C.glEnable(C.GL_TEXTURE_2D)
+	C.glEnable(C.GL_BLEND)
+
 	canvas.ResetOffscreen()
 	canvas.Clear()
 
 	draw(canvas)
 
-	canvas.flush()
+	C.glFlush()
-	canvas.setMainFramebufferOffscreen()
+	canvas.offscreen.SetMainFramebuffer()
 	canvas.Clear()
 
 	scale := float64(canvas.screenScale)
@@ -53,7 +55,7 @@ func (canvas *Canvas) update(draw func(graphics.Canvas)) {
 	geometryMatrix.Scale(scale, scale)
 	canvas.DrawRenderTarget(canvas.screenId,
 		geometryMatrix, matrix.IdentityColor())
-	canvas.flush()
+	C.glFlush()
 }
 
 func (canvas *Canvas) Clear() {
@@ -96,10 +98,8 @@ func (canvas *Canvas) DrawRenderTargetParts(
 	canvas.DrawTextureParts(canvas.ids.ToTexture(id), parts, geometryMatrix, colorMatrix)
 }
 
-// init initializes the canvas. The initial state is saved for each GL canvas.
+func (canvas *Canvas) DrawLines(lines []graphics.Line) {
-func (canvas *Canvas) init() {
+	canvas.offscreen.DrawLines(lines)
-	C.glEnable(C.GL_TEXTURE_2D)
-	C.glEnable(C.GL_BLEND)
 }
 
 func (canvas *Canvas) ResetOffscreen() {
@@ -110,11 +110,3 @@ func (canvas *Canvas) SetOffscreen(renderTargetId graphics.RenderTargetId) {
 	renderTarget := canvas.ids.RenderTargetAt(renderTargetId)
 	canvas.offscreen.Set(renderTarget)
 }
-
-func (canvas *Canvas) setMainFramebufferOffscreen() {
-	canvas.offscreen.SetMainFramebuffer()
-}
-
-func (canvas *Canvas) flush() {
-	C.glFlush()
-}

graphics/opengl/offscreen/offscreen.go

@@ -63,6 +63,10 @@ func (o *Offscreen) DrawTextureParts(texture *gtexture.Texture,
 	texture.DrawParts(parts, &drawable{o, geometryMatrix, colorMatrix})
 }
 
+func (o *Offscreen) DrawLines(lines []graphics.Line) {
+	// TODO: Implement!
+}
+
 type setter struct {
 	offscreen            *Offscreen
 	usingMainFramebuffer bool

graphics/opengl/shader/program.go

@@ -103,9 +103,6 @@ func getUniformLocation(program C.GLuint, name string) C.GLint {
 	return getLocation(program, name, qualifierVariableTypeUniform)
 }
 
-func program() {
-}
-
 func use(projectionMatrix [16]float32,
 	geometryMatrix matrix.Geometry, colorMatrix matrix.Color) C.GLuint {
 	program := programRegular