# Geometry

I2Djs provides a way to define custom geometry using a set of inbuilt geometry APIs. Geometries are used along with custom shader to create out of the box effects.

I2Djs provides APIs for **Mesh**, **line,** and **points** geometry.

### Mesh Geometry:

Used for rendering mesh geometrical polygons. Default drawType is '**TRIANGLES**'. Possible values are '**TRIANGLES**' , '**TRIANGLE\_STRIP**' and '**TRIANGLE\_FAN**'.

```
meshInstance = new MeshGeometry();
```

Example of Mesh Geometry:

```
meshInstance = new MeshGeometry();

geometry.setAttr('a_position', {
		value: new Float32Array([]),
		size: 2
	});
	
geometry.setDrawRange(0, 6);
```

### Line Geometry:

Used for rendering Line geometrical entities like lines, polylines. Default drayType is '**LINE**'. Possible values are '**LINE**', '**LINE\_STRIP**' and '**LINE\_LOOP**'.

```
lineInstance = new LineGeometry();
```

Example of Line Geometry :

```
lineInstance = new LineGeometry();

geometry.setAttr('a_position', {
		value: new Float32Array([]),
		size: 2
	});
	
geometry.setDrawRange(0, 6);
```

### Points Geometry:

Used in rendering points. Default drawType is '**POINT**'.

```
geometry = new PointsGeometry();
```

Example of Points Geometry :

```
geometry = new PointsGeometry();
geometry.setAttr('a_color', {
		value: new Float32Array([255,255,255,255]),
		size: 4
	});
geometry.setAttr('a_size', {
		value: new Float32Array([10]),
		size: 1
	});
geometry.setAttr('a_position', {
		value: new Float32Array([30,40]),
		size: 2
	});
```

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