...

src/cmd/test/main.go

@@ -143,7 +143,7 @@ func main() {
 			gx.MaxColorV,
 		},
 		Visible: true,
-		//Shader: gx.SolidWhiteColorShader,
+		Shader: gx.SolidWhiteColorShader,
 	})
 	e.Run()
 }

src/gx/rect.go

@@ -79,10 +79,11 @@ func (r DrawableRectangle) Draw(
 		return
 	}
 	
+	v := 1
 	opts := &ebiten.DrawRectShaderOptions{
 		GeoM: m,
 		Images: [4]*Image{
-			NewImage(1, 1),
+			NewImage(v, v),
 			nil,
 			nil,
 			nil,
@@ -92,6 +93,6 @@ func (r DrawableRectangle) Draw(
 	//w := int(r.W * r.T.S.X)
 	//h := int(r.H * r.T.S.Y)
 	
-	i.DrawRectShader(1, 1, r.Shader, opts)
+	i.DrawRectShader(v, v, r.Shader, opts)
 }
 

src/gx/shader.go

@@ -8,12 +8,37 @@ import (
 type Shader = ebiten.Shader
 
 var (
-	// The shader does not 
+	// The shader is for example only.
 	SolidWhiteColorShader = MustNewShader([]byte(`
 		package main
 		
-		func Fragment(p vec4, coord vec2, color vec4) vec4 {
-			return vec4(1, 1, 1, 1)
+		func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
+			//ts := imageSrcTextureSize()
+			
+			_, size := imageSrcRegionOnTexture()
+			/*return vec4(
+				position.y/size.y,
+				position.y/size.y,
+				position.y/size.y,
+				position.y/size.y,
+			)*/
+			py := int(position.y / size.y) % 5
+			px := int(position.x / size.x) % 5
+			if py >= 1 && px >= 1 {
+				return vec4(
+					1,
+					0,
+					0,
+					1,
+				)
+			}
+			
+			return vec4(
+				0,
+				1,
+				0,
+				1,
+			)
 		}
 	`))
 )