Files
nmage/assets/textures.go
2022-10-14 07:55:48 +04:00

309 lines
7.6 KiB
Go
Executable File

package assets
import (
"bytes"
"fmt"
"image"
"image/color"
"image/jpeg"
"image/png"
"io"
"os"
"path"
"strings"
"unsafe"
"github.com/go-gl/gl/v4.1-core/gl"
)
type ColorFormat int
const (
ColorFormat_RGBA8 ColorFormat = iota
)
type Texture struct {
//Path only exists for textures loaded from disk
Path string
TexID uint32
Width int32
Height int32
Pixels []byte
}
type TextureLoadOptions struct {
TryLoadFromCache bool
WriteToCache bool
GenMipMaps bool
KeepPixelsInMem bool
}
type Cubemap struct {
// These only exists for textures loaded from disk
RightPath string
LeftPath string
TopPath string
BotPath string
FrontPath string
BackPath string
TexID uint32
}
func LoadTexturePNG(file string, loadOptions *TextureLoadOptions) (Texture, error) {
if loadOptions == nil {
loadOptions = &TextureLoadOptions{}
}
if loadOptions.TryLoadFromCache {
if tex, ok := GetTextureFromCachePath(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,
}
tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
//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)
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]))
if loadOptions.GenMipMaps {
gl.GenerateMipmap(tex.TexID)
}
if loadOptions.WriteToCache {
AddTextureToCache(tex)
}
if !loadOptions.KeepPixelsInMem {
tex.Pixels = nil
}
return tex, nil
}
func LoadTextureInMemPngImg(img image.Image, loadOptions *TextureLoadOptions) (Texture, error) {
if loadOptions == nil {
loadOptions = &TextureLoadOptions{}
}
tex := Texture{}
tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
//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)
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]))
if loadOptions.GenMipMaps {
gl.GenerateMipmap(tex.TexID)
}
if loadOptions.WriteToCache {
AddTextureToCache(tex)
}
if !loadOptions.KeepPixelsInMem {
tex.Pixels = nil
}
return tex, nil
}
func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, error) {
if loadOptions == nil {
loadOptions = &TextureLoadOptions{}
}
if loadOptions.TryLoadFromCache {
if tex, ok := GetTextureFromCachePath(file); ok {
return tex, nil
}
}
//Load from disk
fileBytes, err := os.ReadFile(file)
if err != nil {
return Texture{}, err
}
img, err := jpeg.Decode(bytes.NewReader(fileBytes))
if err != nil {
return Texture{}, err
}
tex := Texture{
Path: file,
}
tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
//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)
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]))
if loadOptions.GenMipMaps {
gl.GenerateMipmap(tex.TexID)
}
if loadOptions.WriteToCache {
AddTextureToCache(tex)
}
if !loadOptions.KeepPixelsInMem {
tex.Pixels = nil
}
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)
}
cmap := Cubemap{
RightPath: rightTex,
LeftPath: leftTex,
TopPath: topTex,
BotPath: botTex,
FrontPath: frontTex,
BackPath: backTex,
}
gl.GenTextures(1, &cmap.TexID)
gl.BindTexture(gl.TEXTURE_CUBE_MAP, cmap.TexID)
// The order here matters
texturePaths := []string{rightTex, leftTex, topTex, botTex, frontTex, backTex}
for i := uint32(0); i < uint32(len(texturePaths)); i++ {
fPath := texturePaths[i]
//Load from disk
fileBytes, err := os.ReadFile(fPath)
if err != nil {
return Cubemap{}, err
}
img, err := imgDecoder(bytes.NewReader(fileBytes))
if err != nil {
return Cubemap{}, err
}
pixels, width, height := pixelDecoder(img)
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]))
}
// set the texture wrapping/filtering options (on the currently bound texture object)
gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE)
return cmap, nil
}