Textures + basic asset loading system+ uvs

assets/textures.go

@@ -0,0 +1,84 @@
+package assets
+
+import (
+	"bytes"
+	"image/color"
+	"image/png"
+	"os"
+	"unsafe"
+
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+type ColorFormat int
+
+const (
+	ColorFormat_RGBA8 ColorFormat = iota
+)
+
+type Texture struct {
+	Path   string
+	TexID  uint32
+	Width  int32
+	Height int32
+	Pixels []byte
+}
+
+func LoadPNG(file string) (Texture, error) {
+
+	if tex, ok := GetTexturePath(file); ok {
+		return tex, nil
+	}
+
+	//Load from disk
+	fileBytes, err := os.ReadFile(file)
+	if err != nil {
+		return Texture{}, err
+	}
+
+	img, err := png.Decode(bytes.NewReader(fileBytes))
+	if err != nil {
+		return Texture{}, err
+	}
+
+	tex := Texture{
+		Path:   file,
+		Width:  int32(img.Bounds().Dx()),
+		Height: int32(img.Bounds().Dy()),
+		Pixels: make([]byte, img.Bounds().Dx()*img.Bounds().Dy()*4),
+	}
+
+	//NOTE: We only support 8-bit channels (32-bit colors) for now
+	i := 0
+	for y := 0; y < img.Bounds().Dy(); y++ {
+		for x := 0; x < img.Bounds().Dx(); x++ {
+
+			c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
+
+			tex.Pixels[i] = c.R
+			tex.Pixels[i+1] = c.G
+			tex.Pixels[i+2] = c.B
+			tex.Pixels[i+3] = c.A
+
+			i += 4
+		}
+	}
+
+	//Prepare opengl stuff
+	gl.GenTextures(1, &tex.TexID)
+	gl.BindTexture(gl.TEXTURE_2D, tex.TexID)
+
+	// set the texture wrapping/filtering options (on the currently bound texture object)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
+
+	// load and generate the texture
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
+	gl.GenerateMipmap(gl.TEXTURE_2D)
+
+	SetTexture(tex)
+
+	return tex, nil
+}