Texture Sheets

Texture sheets are often used to collect many icons into a single texture. They are commonly used in GUIs where multiple components are composed dynamically. This normally requires UV coordinates hard-coded in the source.

To give resource packs more flexibility, DragonLib introduces a new section in texture.png.mcmeta files where sprites can be defined outside the code.

Creating the files

Assume you have a texture named sprite_sheet.png in your assets. Add a mcmeta file next to it:

sprite_sheet.png
sprite_sheet.png.mcmeta

In the mcmeta add a dragonlib-gui section:

{
  "dragonlib-gui": {
    "texture_size": [256, 256],   // Texture size in pixels
    "sprites": {
      // Sprite definitions with UVs and other properties
    }
  }
}

Defining sprites

Instead of hard-coding UVs, list sprites in this file. Resource packs can override it. Different sprite types determine rendering and available properties.

Example:

"custom_icon": {
  "type": "stretched",      // Rendering type
  "uv": [20, 5],            // UV start coordinates
  "size": [5, 5]            // Size on the texture sheet
}

stretched

The sprite is rendered stretched into the target area and may be distorted if sizes don't match.

Properties:

• uv (int[2]) — x, y start coordinates on the sheet.
• size (int[2]) — width, height on the sheet.

Example:

"icon": {
  "type": "stretched",
  "uv": [64, 128],
  "size": [16, 16]
}

tiled

The sprite is rendered at its original size and repeated or clipped to fill the target area. No distortion occurs.

Properties:

• uv (int[2])
• size (int[2])

Example:

"dirt_background": {
  "type": "tiled",
  "uv": [0, 0],
  "size": [16, 16]
}

nine_slice

A nine-slice sprite consists of 9 parts: corners, edges and center. This allows scalable framed sprites (e.g., buttons). The parts are arranged in a 3×3 grid.

Properties:

• uv (int[2]) — x, y start coordinates.
• size (int[2]) — width, height on the sheet.
• border (int[4]) — left, top, right, bottom border sizes in pixels.
• tiledContent (boolean) — if true, center is tiled; if false, center is stretched.
• tiledBorder (boolean) — if true, borders are tiled; if false, borders are stretched.

Example:

"button_selected": {
  "type": "nine_slice",
  "uv": [10, 5],
  "size": [5, 5],
  "border": [2, 2, 2, 2],
  "tiledContent": true,
  "tiledBorder": false
}

Example (full file):

{
  "dragonlib-gui": {
    "texture_size": [256, 256],
    "sprites": {
      "button_gray_disabled": {
        "type": "nine_slice",
        "uv": [20, 5],
        "size": [5, 5],
        "border": [2, 2, 2, 2]
      },
      "button_gray_normal": {
        "type": "nine_slice",
        "uv": [0, 5],
        "size": [5, 5],
        "border": [2, 2, 2, 2]
      },
      "button_gray_selected": {
        "type": "nine_slice",
        "uv": [5, 5],
        "size": [5, 5],
        "border": [2, 2, 2, 2]
      },
      "button_gray_down_selected": {
        "type": "nine_slice",
        "uv": [10, 5],
        "size": [5, 5],
        "border": [2, 2, 2, 2]
      },
      "button_gray_down": {
        "type": "nine_slice",
        "uv": [15, 5],
        "size": [5, 5],
        "border": [2, 2, 2, 2]
      }
    }
  }
}

Usage

Create a DLTextureSheet with the texture resource location:

DLTextureSheet sheet = new DLTextureSheet(new ResourceLocation("examplemod", "textures/gui/texture_sheet.png"));

Load a sprite by name:

AbstractSprite sprite = sheet.getSprite("my_sprite");

AbstractSprite provides common properties. Specific types (e.g., StretchedSprite) inherit from it. The variants are inner classes of DLTextureSheetData.

Render a sprite:

sprite.render(graphics, 0, 0, 16, 16);  // position and rendered size

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Categories: DragonLib