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