Refactoring

graphics/opengl/context.go

@@ -56,8 +56,6 @@ func (context *Context) Init() {
 		panic("creating main framebuffer failed: " + err.Error())
 	}
 
-	shader.Init()
-
 	context.screenId, err = context.NewRenderTarget(
 		context.screenWidth, context.screenHeight)
 	if err != nil {
@@ -83,36 +81,30 @@ func (context *Context) Fill(r, g, b uint8) {
 	C.glClear(C.GL_COLOR_BUFFER_BIT)
 }
 
-type TextureDrawing struct {
-	projectionMatrix [16]float32
-	geometryMatrix   matrix.Geometry
-	colorMatrix      matrix.Color
-}
-
-func (t *TextureDrawing) Draw(native interface{}, quads []texture.Quad) {
-	shader.DrawTexture(uint(native.(C.GLuint)), t.projectionMatrix, quads, t.geometryMatrix, t.colorMatrix)
-}
-
 func (context *Context) DrawTexture(
 	textureId graphics.TextureId,
 	geometryMatrix matrix.Geometry, colorMatrix matrix.Color) {
-	texture, ok := context.textures[textureId]
+	tex, ok := context.textures[textureId]
 	if !ok {
 		panic("invalid texture ID")
 	}
-	drawing := &TextureDrawing{context.projectionMatrix, geometryMatrix, colorMatrix}
+	tex.Draw(func(native interface{}, quads []texture.Quad) {
-	texture.Draw(drawing.Draw)
+		shader.DrawTexture(uint(native.(C.GLuint)), context.projectionMatrix, quads,
+			geometryMatrix, colorMatrix)
+	})
 }
 
 func (context *Context) DrawTextureParts(
 	textureId graphics.TextureId, parts []graphics.TexturePart,
 	geometryMatrix matrix.Geometry, colorMatrix matrix.Color) {
-	texture, ok := context.textures[textureId]
+	tex, ok := context.textures[textureId]
 	if !ok {
 		panic("invalid texture ID")
 	}
-	drawing := &TextureDrawing{context.projectionMatrix, geometryMatrix, colorMatrix}
+	tex.DrawParts(parts, func(native interface{}, quads []texture.Quad) {
-	texture.DrawParts(parts, drawing.Draw)
+		shader.DrawTexture(uint(native.(C.GLuint)), context.projectionMatrix, quads,
+			geometryMatrix, colorMatrix)
+	})
 }
 
 func (context *Context) ResetOffscreen() {
@@ -170,8 +162,6 @@ func (v *viewportSetter) Set(x, y, width, height int) {
 			v.context.projectionMatrix[i+j*4] = float32(matrix[i][j])
 		}
 	}
-
-	// TODO: call 'setShaderProgram' here?
 }
 
 func (context *Context) setMainFramebufferOffscreen() {
@@ -204,7 +194,7 @@ func (context *Context) NewRenderTarget(width, height int) (
 
 func (context *Context) NewTextureFromImage(img image.Image) (
 	graphics.TextureId, error) {
-	texture, err := texture.NewFromImage(img, &NativeTextureCreator{})
+	texture, err := texture.NewFromImage(img, createFromImage)
 	if err != nil {
 		return 0, err
 	}

graphics/opengl/shader/shader.go

@@ -114,7 +114,11 @@ func createProgram(shaders ...*shader) C.GLuint {
 	return program
 }
 
-func Init() {
+var (
+	initialized = false
+)
+
+func initialize() {
 	// TODO: when should this function be called?
 	vertexShader.id = C.glCreateShader(C.GL_VERTEX_SHADER)
 	if vertexShader.id == 0 {
@@ -139,6 +143,8 @@ func Init() {
 	C.glDeleteShader(vertexShader.id)
 	C.glDeleteShader(fragmentShader.id)
 	C.glDeleteShader(colorMatrixShader.id)
+
+	initialized = true
 }
 
 const (
@@ -246,6 +252,10 @@ func use(projectionMatrix [16]float32, geometryMatrix matrix.Geometry, colorMatr
 
 func DrawTexture(native uint, projectionMatrix [16]float32, quads []texture.Quad,
 	geometryMatrix matrix.Geometry, colorMatrix matrix.Color) {
+	if !initialized {
+		initialize()
+	}
+
 	if len(quads) == 0 {
 		return
 	}

graphics/opengl/texture.go

@@ -36,19 +36,17 @@ func createNativeTexture(textureWidth, textureHeight int, pixels []uint8) C.GLui
 	return nativeTexture
 }
 
-type NativeTextureCreator struct{}
+func create(textureWidth, textureHeight int) (interface{}, error) {
-
-func (creator *NativeTextureCreator) Create(textureWidth, textureHeight int) (interface{}, error) {
 	return createNativeTexture(textureWidth, textureHeight, nil), nil
 }
 
-func (creator *NativeTextureCreator) CreateFromImage(img *image.NRGBA) (interface{}, error) {
+func createFromImage(img *image.NRGBA) (interface{}, error) {
 	size := img.Bounds().Size()
 	return createNativeTexture(size.X, size.Y, img.Pix), nil
 }
 
 func newRenderTarget(width, height int) (*rendertarget.RenderTarget, error) {
-	texture, err := texture.New(width, height, &NativeTextureCreator{})
+	texture, err := texture.New(width, height, create)
 	if err != nil {
 		return nil, err
 	}
@@ -57,7 +55,7 @@ func newRenderTarget(width, height int) (*rendertarget.RenderTarget, error) {
 }
 
 func newRenderTargetWithFramebuffer(width, height int, framebuffer C.GLuint) (*rendertarget.RenderTarget, error) {
-	texture, err := texture.New(width, height, &NativeTextureCreator{})
+	texture, err := texture.New(width, height, create)
 	if err != nil {
 		return nil, err
 	}

graphics/texture/texture.go

@@ -23,24 +23,20 @@ type Texture struct {
 	height int
 }
 
-func New(width, height int, creator interface {
+func New(width, height int, create func(textureWidth, textureHeight int) (interface{}, error)) (*Texture, error) {
-	Create(textureWidth, textureHeight int) (interface{}, error)
-}) (*Texture, error) {
 	texture := &Texture{
 		width:  width,
 		height: height,
 	}
 	var err error
-	texture.native, err = creator.Create(texture.textureWidth(), texture.textureHeight())
+	texture.native, err = create(texture.textureWidth(), texture.textureHeight())
 	if err != nil {
 		return nil, err
 	}
 	return texture, nil
 }
 
-func NewFromImage(img image.Image, creator interface {
+func NewFromImage(img image.Image, create func(img *image.NRGBA) (interface{}, error)) (*Texture, error) {
-	CreateFromImage(img *image.NRGBA) (interface{}, error)
-}) (*Texture, error) {
 	size := img.Bounds().Size()
 	width, height := size.X, size.Y
 	texture := &Texture{
@@ -58,7 +54,7 @@ func NewFromImage(img image.Image, creator interface {
 	}
 	draw.Draw(adjustedImage, dstBound, img, image.ZP, draw.Src)
 	var err error
-	texture.native, err = creator.CreateFromImage(adjustedImage)
+	texture.native, err = create(adjustedImage)
 	if err != nil {
 		return nil, err
 	}