feat: initial commit

internal/render/gif.go

@@ -0,0 +1,63 @@
+package render
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	"image/color/palette"
+	"image/draw"
+	"image/gif"
+
+	"github.com/hytale-tools/blockymodel-merger/pkg/texture"
+)
+
+// RenderGIF renders a GLB model to an animated GIF rotating 360 degrees
+func RenderGIF(glbBytes []byte, atlas *texture.Atlas, background string, frames, width, height, delay int) ([]byte, error) {
+	// Parse background color
+	bgColor, err := ParseHexColor(background)
+	if err != nil {
+		return nil, fmt.Errorf("invalid background color: %w", err)
+	}
+
+	// Get atlas image
+	var atlasImage = atlas.Image
+
+	// Convert GLB to mesh
+	mesh, err := GLBToMesh(glbBytes, atlasImage)
+	if err != nil {
+		return nil, fmt.Errorf("converting GLB to mesh: %w", err)
+	}
+
+	// Calculate rotation per frame
+	rotationPerFrame := 360.0 / float64(frames)
+
+	// Create GIF structure
+	g := &gif.GIF{
+		Image:     make([]*image.Paletted, frames),
+		Delay:     make([]int, frames),
+		LoopCount: 0, // 0 = infinite loop
+	}
+
+	// Render each frame
+	for i := 0; i < frames; i++ {
+		rotation := float64(i) * rotationPerFrame
+
+		// Render frame
+		img := RenderScene(mesh, atlasImage, rotation, width, height, bgColor)
+
+		// Quantize to palette
+		paletted := image.NewPaletted(img.Bounds(), palette.Plan9)
+		draw.FloydSteinberg.Draw(paletted, img.Bounds(), img, image.Point{})
+
+		g.Image[i] = paletted
+		g.Delay[i] = delay
+	}
+
+	// Encode GIF
+	var buf bytes.Buffer
+	if err := gif.EncodeAll(&buf, g); err != nil {
+		return nil, fmt.Errorf("encoding GIF: %w", err)
+	}
+
+	return buf.Bytes(), nil
+}