Use sRGBA on GPU as PNG/JPEG generally uses that nowadays

assets/textures.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"image"
-	"image/color"
 	"image/jpeg"
 	"image/png"
 	"io"
@@ -14,6 +13,7 @@ import (
 	"unsafe"
 
 	"github.com/go-gl/gl/v4.1-core/gl"
+	"github.com/mandykoh/prism"
 )
 
 type ColorFormat int
@@ -67,17 +67,20 @@ func LoadTexturePNG(file string, loadOptions *TextureLoadOptions) (Texture, erro
 		return Texture{}, err
 	}
 
-	img, err := png.Decode(bytes.NewReader(fileBytes))
+	bytesReader := bytes.NewReader(fileBytes)
+	img, err := png.Decode(bytesReader)
 	if err != nil {
 		return Texture{}, err
 	}
 
+	nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
 	tex := Texture{
 		Path:   file,
+		Pixels: nrgbaImg.Pix,
+		Height: int32(nrgbaImg.Bounds().Dy()),
+		Width:  int32(nrgbaImg.Bounds().Dx()),
 	}
 
-	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
-
 	//Prepare opengl stuff
 	gl.GenTextures(1, &tex.TexID)
 	gl.BindTexture(gl.TEXTURE_2D, tex.TexID)
@@ -89,7 +92,7 @@ func LoadTexturePNG(file string, loadOptions *TextureLoadOptions) (Texture, erro
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.SRGB8_ALPHA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 
 	if loadOptions.GenMipMaps {
 		gl.GenerateMipmap(tex.TexID)
@@ -112,8 +115,13 @@ func LoadTextureInMemPngImg(img image.Image, loadOptions *TextureLoadOptions) (T
 		loadOptions = &TextureLoadOptions{}
 	}
 
-	tex := Texture{}
+	nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
-	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
+	tex := Texture{
+		Path:   "",
+		Pixels: nrgbaImg.Pix,
+		Height: int32(nrgbaImg.Bounds().Dy()),
+		Width:  int32(nrgbaImg.Bounds().Dx()),
+	}
 
 	//Prepare opengl stuff
 	gl.GenTextures(1, &tex.TexID)
@@ -126,7 +134,7 @@ func LoadTextureInMemPngImg(img image.Image, loadOptions *TextureLoadOptions) (T
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.SRGB8_ALPHA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 
 	if loadOptions.GenMipMaps {
 		gl.GenerateMipmap(tex.TexID)
@@ -166,12 +174,14 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 		return Texture{}, err
 	}
 
+	nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
 	tex := Texture{
 		Path:   file,
+		Pixels: nrgbaImg.Pix,
+		Height: int32(nrgbaImg.Bounds().Dy()),
+		Width:  int32(nrgbaImg.Bounds().Dx()),
 	}
 
-	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
-
 	//Prepare opengl stuff
 	gl.GenTextures(1, &tex.TexID)
 	gl.BindTexture(gl.TEXTURE_2D, tex.TexID)
@@ -183,7 +193,7 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.SRGB8_ALPHA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 
 	if loadOptions.GenMipMaps {
 		gl.GenerateMipmap(tex.TexID)
@@ -200,65 +210,14 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 	return tex, nil
 }
 
-func pixelsFromNrgbaPng(img image.Image) (pixels []byte, width, height int32) {
-
-	//NOTE: Load bottom left to top right because this is the texture coordinate system used by OpenGL
-	//NOTE: We only support 8-bit channels (32-bit colors) for now
-	i := 0
-	width, height = int32(img.Bounds().Dx()), int32(img.Bounds().Dy())
-	pixels = make([]byte, img.Bounds().Dx()*img.Bounds().Dy()*4)
-	for y := img.Bounds().Dy() - 1; y >= 0; y-- {
-		for x := 0; x < img.Bounds().Dx(); x++ {
-
-			c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
-
-			pixels[i] = c.R
-			pixels[i+1] = c.G
-			pixels[i+2] = c.B
-			pixels[i+3] = c.A
-
-			i += 4
-		}
-	}
-
-	return pixels, width, height
-}
-
-func pixelsFromNrgbaJpg(img image.Image) (pixels []byte, width, height int32) {
-
-	//NOTE: Load bottom left to top right because this is the texture coordinate system used by OpenGL
-	//NOTE: We only support 8-bit channels (32-bit colors) for now
-	i := 0
-	width, height = int32(img.Bounds().Dx()), int32(img.Bounds().Dy())
-	pixels = make([]byte, img.Bounds().Dx()*img.Bounds().Dy()*4)
-	for y := img.Bounds().Dy() - 1; y >= 0; y-- {
-		for x := 0; x < img.Bounds().Dx(); x++ {
-
-			c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
-
-			pixels[i] = c.R
-			pixels[i+1] = c.G
-			pixels[i+2] = c.B
-			pixels[i+3] = c.A
-
-			i += 4
-		}
-	}
-
-	return pixels, width, height
-}
-
 func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex string) (Cubemap, error) {
 
 	var imgDecoder func(r io.Reader) (image.Image, error)
-	var pixelDecoder func(image.Image) ([]byte, int32, int32)
 	ext := strings.ToLower(path.Ext(rightTex))
 	if ext == ".jpg" || ext == ".jpeg" {
 		imgDecoder = jpeg.Decode
-		pixelDecoder = pixelsFromNrgbaJpg
 	} else if ext == ".png" {
 		imgDecoder = png.Decode
-		pixelDecoder = pixelsFromNrgbaPng
 	} else {
 		return Cubemap{}, fmt.Errorf("unknown image extension: %s. Expected one of: .jpg, .jpeg, .png", ext)
 	}
@@ -292,9 +251,11 @@ func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex st
 			return Cubemap{}, err
 		}
 
-		pixels, width, height := pixelDecoder(img)
+		nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
+		height := int32(nrgbaImg.Bounds().Dy())
+		width := int32(nrgbaImg.Bounds().Dx())
 
-		gl.TexImage2D(uint32(gl.TEXTURE_CUBE_MAP_POSITIVE_X)+i, 0, gl.RGBA8, int32(width), int32(height), 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&pixels[0]))
+		gl.TexImage2D(uint32(gl.TEXTURE_CUBE_MAP_POSITIVE_X)+i, 0, gl.RGBA8, int32(width), int32(height), 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&nrgbaImg.Pix[0]))
 	}
 
 	// set the texture wrapping/filtering options (on the currently bound texture object)

go.mod

@@ -12,3 +12,8 @@ require (
 )
 
 require github.com/AllenDang/cimgui-go v0.0.0-20230720025235-f2ff398a66b2
+
+require (
+	github.com/mandykoh/go-parallel v0.1.0 // indirect
+	github.com/mandykoh/prism v0.35.1 // indirect
+)

go.sum

@@ -6,5 +6,34 @@ github.com/bloeys/gglm v0.43.0 h1:ZpOghR3PHfpkigTDh+FqxLsF0gN8CD6s/bWoei6LyxI=
 github.com/bloeys/gglm v0.43.0/go.mod h1:qwJQ0WzV191wAMwlGicbfbChbKoSedMk7gFFX6GnyOk=
 github.com/go-gl/gl v0.0.0-20211210172815-726fda9656d6 h1:zDw5v7qm4yH7N8C8uWd+8Ii9rROdgWxQuGoJ9WDXxfk=
 github.com/go-gl/gl v0.0.0-20211210172815-726fda9656d6/go.mod h1:9YTyiznxEY1fVinfM7RvRcjRHbw2xLBJ3AAGIT0I4Nw=
+github.com/mandykoh/go-parallel v0.1.0 h1:7vJMNMC4dsbgZdkAb2A8tV5ENY1v7VxIO1wzQWZoT8k=
+github.com/mandykoh/go-parallel v0.1.0/go.mod h1:lkYHqG1JNTaSS6lG+PgFCnyMd2VDy8pH9jN9pY899ig=
+github.com/mandykoh/prism v0.35.1 h1:JbQfQarANxSWlgJEpjv+E7DvtrqBaVP1YgJfZPvo6ME=
+github.com/mandykoh/prism v0.35.1/go.mod h1:3miB3EAJ0IggYl/4eBB5MmawRbyJI1gKDtbrVvk8Q9I=
 github.com/veandco/go-sdl2 v0.4.35 h1:NohzsfageDWGtCd9nf7Pc3sokMK/MOK+UA2QMJARWzQ=
 github.com/veandco/go-sdl2 v0.4.35/go.mod h1:OROqMhHD43nT4/i9crJukyVecjPNYYuCofep6SNiAjY=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/image v0.5.0/go.mod h1:FVC7BI/5Ym8R25iw5OLsgshdUBbT1h5jZTpA+mvAdZ4=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
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