Mi³ Engine is a very basic and lightweight rendering engine written in Java intended to render Minecraft elements such as resource pack models.

Table of Contents

• Performances
• Usage :
  • Manual
  • Model Parser Tool
  • Skin Render Tool
  • Auto Framer Tool
• Future

Performances

Performances are not adapted to video or live preview but are still suitable for efficient image generation. Generating an image of 1287x1287 for a large model containing 400 cubes takes about 100ms (depends of the hardware of course).

Usage

This engine is written in Java 17 (maybe compatible with Java 15 but not tested). It can be added to your project using Maven:

<dependency>
    <groupId>io.github.mrmiumo</groupId>
    <artifactId>mi3engine</artifactId>
    <version>1.1.2</version>
</dependency>

Once imported in your project, you can use it by yourself (creating and adding cubes one by one) or using tools.

Manual Usage

This technique enabled you to have full control over what is used to generate your images. It is adapted when no tool already exist for your use case.
Here is a small example:

/* Step 1. Create the engine */
RenderEngine engine = RenderEngine.from(1920, 1080);

/* Step 2. Setup the camera */
engine.camera()
    .setRotation(25, -145, 0)
    .setTranslation(1, 0)
    .setZoom(0.32);

/* Step 3. Load your textures */
Texture texture = Texture.from(Path.of("myTexture.png"));

/* Step 4. Create the cubes */
Cube.from(new Vec(16, 0, 16), new Vec(32, 8,  32))
    .rotation(0, Axis.Y)
    .pivot(8, 0, 16)
    .texture(Face.NORTH, texture, 0, 8, 16, 16, 0)
    .texture(Face.EAST, texture, 0, 8, 16, 16, 1)
    .texture(Face.SOUTH, texture, 0, 8, 16, 16, 1)
    .texture(Face.WEST, texture, 0, 8, 16, 16, 1)
    .texture(Face.UP, texture, 0, 0, 16, 16, 1)
    .texture(Face.DOWN, texture, 0, 0, 16, 16, 0)
    .render(engine);

/* Step 5. Render the image */
BufferedImage output = engine.render();

/* Step 6. Save the image */
ImageIO.write(output, "PNG", Files.newOutputStream("MyImage.png"));

Model Parser Tool

This method make the rendering way much easier. Tools are built-in classes that enabled to generate images for some Minecraft components such as pack models. Here is an example:

/* Step 1. Create a new parser with an engine */
ModelParser engine = new ModelParser(RenderEngine.from(1287, 1287));

/* Step 2. Setup the camera */
engine.camera()
    .setRotation(25, -145, 0)
    .setTranslation(1, 0)
    .setZoom(0.32);

/* Step 3. Use the tool to convert a file and collect the created cubes */
engine.parse(pack.resolve("assets/minecraft/models/item/boat.json"));

/* Step 4. Render the image */
BufferedImage output = engine.render();

/* Step 5. Save the image */
ImageIO.write(output, "PNG", Files.newOutputStream("MyImage.png"));

IMPORTANT: When using the ModelParser, you must define a property called 'default.minecraft.pack' in your application.properties file to give the path to a folder corresponding to the default minecraft resource pack. If your project does not have such a file yet, add it in the src/main/resources folder and add the line:

default.minecraft.pack=/myApp/assets/minecraftDefaultTextures

This configuration is important since most models rely on default game's textures and those are not embedded in the engine.

Skin Render Tool

This tools enables to create skin render with custom poses. This module is not perfect yet and lacks a few features. Here is the list of features support:

Feature	Description	Supported since
Basic Poses	Move head, arms and legs	v1.1.0
Arm bending	Curvate each arm at elbows	v1.1.0
Leg bending	Curvate each leg at knees	:v1.1.3:
Second layer	Upper skin layer is rendered	v1.1.0
3D Second layer	Improved second layer with true depth	❌
Slim skin	'Alex' skin with 3px large arms	v1.1.1
Hat	Enable to add model on head	v1.1.1
Item holding	Enable to add model in hands	❌
Armor	Equip armor pieces on the player	Not planned yet

Here is an example of usage:

/* Step 1. Create a new parser with an engine */
Path mySkin = Path.of("path/to/myskin.png");
SkinRender engine = new SkinRender(RenderEngine.from(1287, 1287), mySkin);

/* Step 2. Setup the camera */
engine.camera()
    .setRotation(5, 25, 0)
    .setTranslation(0, 0)
    .setZoom(0.4)
    .setAmbientLight(0.25f)
    .setSpotLight(7)
    .setSpotDirection(new Vec(1, 1, .15));

/* Step 3. Use the tool to create a pose */
engine.head(new Vec(-5, -8, 3))
    .rightArm(new Vec(-70, 75, 30), 75)
    .leftArm(new Vec(0, 0, 0), 0)
    .leftArm(new Vec(0, 25, 10), 35)
    .rightLeg(new Vec(5, -20, -5))
    .leftLeg(new Vec(25, -10, 15));

/* Step 4. Render the image */
BufferedImage output = engine.render();

/* Step 5. Save the image */
ImageIO.write(output, "PNG", Files.newOutputStream("MyImage.png"));

To equip models on the skin, use the equip function as bellow:

// We use a small trick to avoid creating a real engine here!
var hat = new ModelParser(new Group().asEngine())
    .parse(pack.resolve("models/hatDemo1.json"));
engine.equip(Slot.HEAD, hat);

AutoFramer Tool

The AutoFramer tool is a patch above the render engine. It can be used alongside with any other tool!
Its goal is to center the object and adjust the zoom automatically to make the object fill the final image.

/* Step 1. Create the engine with AutoFramer */
RenderEngine engine = new AutoFramer(RenderEngine.from(1287, 1287));

/* Step 2. Setup the camera */
engine.camera().setRotation(25, -145, 0);

/* Step 3. Add the cubes to the engine */
engine.addCubes(myCubes);

/* Step 5. Render the image */
BufferedImage output = engine.render();

/* Step 6. Save the image */
ImageIO.write(output, "PNG", Files.newOutputStream("MyImage.png"));