原始提交

model/texture.go

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2022. Gardel <sunxinao@hotmail.com> and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package model
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"image"
+	"image/color"
+	"time"
+)
+
+type Texture struct {
+	Hash      string `gorm:"size:64;primaryKey"`
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	Data      []byte `gorm:"not null"`
+	Used      uint   `gorm:"not null"`
+}
+
+func ComputeTextureId(img image.Image) string {
+	digest := sha256.New()
+	bound := img.Bounds()
+	width := bound.Dx()
+	height := bound.Dy()
+	var buf [4096]byte
+
+	putInt(buf[:], int32(width))
+	putInt(buf[4:], int32(height))
+	var pos = 8
+	for x := 0; x < width; x++ {
+		for y := 0; y < height; y++ {
+			rgba := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
+			if rgba.A == 0 {
+				copy(buf[pos:], []byte{0, 0, 0, 0})
+			} else {
+				copy(buf[pos:], []byte{rgba.A, rgba.R, rgba.G, rgba.B})
+			}
+			pos += 4
+			if pos == len(buf) {
+				pos = 0
+				digest.Write(buf[:])
+			}
+		}
+	}
+	if pos > 0 {
+		digest.Write(buf[:pos])
+	}
+	return hex.EncodeToString(digest.Sum(nil))
+}
+
+func putInt(buf []byte, n int32) {
+	buf[0] = byte(n >> 24 & 0xff)
+	buf[1] = byte(n >> 16 & 0xff)
+	buf[2] = byte(n >> 8 & 0xff)
+	buf[3] = byte(n & 0xff)
+}