Add TestPattern

example/game/testpattern/testpattern.go

@@ -0,0 +1,79 @@
+package testpattern
+
+import (
+	"github.com/hajimehoshi/go-ebiten"
+	"github.com/hajimehoshi/go-ebiten/graphics"
+	"github.com/hajimehoshi/go-ebiten/graphics/matrix"
+	"image"
+	_ "image/png"
+	"math"
+	"os"
+)
+
+type TestPattern struct {
+	textureId     graphics.TextureID
+	textureWidth  int
+	textureHeight int
+	geos          []matrix.Geometry
+}
+
+func New() *TestPattern {
+	return &TestPattern{}
+}
+
+func (game *TestPattern) Init(tf graphics.TextureFactory) {
+	file, err := os.Open("images/test_pattern.png")
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close()
+
+	img, _, err := image.Decode(file)
+	if err != nil {
+		panic(err)
+	}
+	if game.textureId, err = tf.NewTextureFromImage(img); err != nil {
+		panic(err)
+	}
+	size := img.Bounds().Size()
+	game.textureWidth = size.X
+	game.textureHeight = size.Y
+}
+
+func (game *TestPattern) Update(context ebiten.GameContext) {
+	geo := matrix.IdentityGeometry()
+	geo.Translate(13, 13)
+	game.geos = append(game.geos, geo)
+
+	geo = matrix.IdentityGeometry()
+	geo.Translate(float64(13+game.textureWidth), 13)
+	game.geos = append(game.geos, geo)
+
+	geo = matrix.IdentityGeometry()
+	geo.Translate(float64(13+game.textureWidth*2), 13)
+	game.geos = append(game.geos, geo)
+
+	geo = matrix.IdentityGeometry()
+	geo.Translate(float64(13+game.textureWidth*3), 13)
+	game.geos = append(game.geos, geo)
+
+	geo = matrix.IdentityGeometry()
+	geo.Scale(2, 2)
+	geo.Translate(13, float64(13+game.textureHeight))
+	game.geos = append(game.geos, geo)
+
+	geo = matrix.IdentityGeometry()
+	geo.Rotate(math.Pi)
+	geo.Scale(2, 2)
+	geo.Translate(float64(game.textureWidth*2),
+		float64(game.textureHeight*2))
+	geo.Translate(float64(13+game.textureWidth*2),
+		float64(13+game.textureHeight))
+	game.geos = append(game.geos, geo)
+}
+
+func (game *TestPattern) Draw(g graphics.Context) {
+	for _, geo := range game.geos {
+		g.DrawTexture(game.textureId, geo, matrix.IdentityColor())
+	}
+}

example/main.go

@@ -8,6 +8,7 @@ import (
 	"github.com/hajimehoshi/go-ebiten/example/game/rects"
 	"github.com/hajimehoshi/go-ebiten/example/game/rotating"
 	"github.com/hajimehoshi/go-ebiten/example/game/sprites"
+	"github.com/hajimehoshi/go-ebiten/example/game/testpattern"
 	"github.com/hajimehoshi/go-ebiten/ui"
 	"github.com/hajimehoshi/go-ebiten/ui/cocoa"
 	"github.com/hajimehoshi/go-ebiten/ui/glut"
@@ -43,6 +44,8 @@ func main() {
 		game = rotating.New()
 	case "sprites":
 		game = sprites.New()
+	case "testpattern":
+		game = testpattern.New()
 	}
 
 	const screenWidth = 256

graphics/graphics.go

@@ -19,7 +19,7 @@ type TexturePart struct {
 }
 
 type Context interface {
-	ToTexture(renderTargetID RenderTargetID) TextureID
+	ToTexture(id RenderTargetID) TextureID
 
 	Clear()
 	Fill(r, g, b uint8)

graphics/opengl/context.go

@@ -141,13 +141,6 @@ func (context *Context) ResetOffscreen() {
 	context.setOffscreen(context.screen)
 }
 
-func abs(x int) int {
-	if x < 0 {
-		return -x
-	}
-	return x
-}
-
 func (context *Context) SetOffscreen(renderTargetID graphics.RenderTargetID) {
 	renderTarget := context.textures[C.GLuint(renderTargetID)]
 	context.setOffscreen(renderTarget)
@@ -168,8 +161,8 @@ func (context *Context) setOffscreen(renderTarget *Texture) {
 	C.glBlendFuncSeparate(C.GL_SRC_ALPHA, C.GL_ONE_MINUS_SRC_ALPHA,
 		C.GL_ZERO, C.GL_ONE)
 
-	C.glViewport(0, 0, C.GLsizei(abs(renderTarget.textureWidth)),
-		C.GLsizei(abs(renderTarget.textureHeight)))
+	C.glViewport(0, 0, C.GLsizei(renderTarget.textureWidth),
+		C.GLsizei(renderTarget.textureHeight))
 }
 
 func (context *Context) setMainFramebufferOffscreen() {