Moved all into one package, added png loader.

loader.go

@@ -0,0 +1,58 @@
+package goga
+
+import (
+	"github.com/go-gl/gl/v4.5-core/gl"
+	"image"
+	"image/draw"
+	"image/png"
+	"os"
+)
+
+// Loads textures from png files.
+// If keepData is set to true,
+// pixel data will be stored inside the texture
+// (additionally to VRAM).
+type PngLoader struct {
+	Filter   int32
+	KeepData bool
+}
+
+func (p *PngLoader) Load(file string) (Res, error) {
+	// load texture
+	imgFile, err := os.Open(file)
+
+	if err != nil {
+		return nil, err
+	}
+
+	img, err := png.Decode(imgFile)
+
+	if err != nil {
+		return nil, err
+	}
+
+	rgba := image.NewRGBA(img.Bounds())
+	draw.Draw(rgba, rgba.Bounds(), img, image.Point{0, 0}, draw.Src)
+
+	// create GL texture
+	tex := NewTex(gl.TEXTURE_2D)
+	tex.Bind()
+	tex.SetDefaultParams(p.Filter)
+	tex.Texture2D(0,
+		gl.RGBA,
+		int32(rgba.Rect.Size().X),
+		int32(rgba.Rect.Size().Y),
+		gl.RGBA,
+		gl.UNSIGNED_BYTE,
+		rgba.Pix)
+
+	if p.KeepData {
+		tex.SetRGBA(rgba)
+	}
+
+	return tex, nil
+}
+
+func (p *PngLoader) Ext() string {
+	return "png"
+}