Simple Shapes

When you're quickly prototyping something or just getting started with LÖVR, it can be helpful to draw some simple shapes. These are sometimes called "graphics primitives". Note that all units for positions, sizes, etc. are in meters.

Colors

To change the color of a primitive, call lovr.graphics.setColor(r, g, b) before you draw the primitive. The r, g, b parameters are the red, green, and blue components of the color, like you would find in Photoshop. (255, 255, 255) is white, (0, 0, 0) is black, and (0, 0, 128) is darkish blue. Note that the color will remain active until it's changed again.

Points

lovr.graphics.points(x, y, z)

This draws a single point at an x, y, z position in 3D space. If you try it out and draw a point at (0, 0, 0), the point will be really hard to see because it's only 1 pixel big! To change this, have a look at the lovr.graphics.setPointSize function. You can also draw more than one point by passing in more point coordinates after the first. Finally, you can also pass in a table:

local points = {
  0, 0, 0,
  1, 1, 1
}

lovr.graphics.points(points)

Lines

lovr.graphics.line(x1, y1, z1, x2, y2, z2, ...)

This function draws lines between points. Here's how you would draw a square on the floor:

lovr.graphics.line(
  -1, 0, -1,
  -1, 0,  1,
   1, 0,  1,
   1, 0, -1
)

Triangles

lovr.graphics.triangle(mode, x1, y1, z1, x2, y2, z2, x3, y3, z3)

This function draws a triangle from the specified 3 points. mode can either be line for a wireframe triangle or fill for a solid triangle.

Planes

A plane is a flat rectangle. They can be used for simple floors and walls.

lovr.graphics.plane(mode, x, y, z, size, nx, ny, nz)

This draws a plane size meters big centered at (x, y, z). To control the direction the plane is facing, you gotta specify a normal vector. The normal vector is a direction specified using 3 numbers (x, y, and z). The normal vector (0, 1, 0) is a vector that points straight up, because the x and z parts of the direction are zero and the y direction of the vector is positive 1, which is straight up.

Cubes

Finally, cubes, the pinnacle of primitives.

lovr.graphics.cube(mode, x, y, z, size, angle, ax, ay, az)

This function draws a cube. You can draw it as a wireframe or as a filled cube using the mode parameter, similar to triangles and planes. The x, y, and z parameters control the position. The size parameter controls how big it is. Finally, the last four parameters control the cube's rotation. The first number is the number of radians to rotate the cube around its axis of rotation, and the last three numbers define the x, y, and z components of the axis of rotation. This is called "angle axis representation". It's honestly pretty confusing, but LÖVR plans to add some utilities to make this easier in the future!

Bonus!!

Planes and cubes can have textures applied to them. Here's how you would draw a plane on the ground with a ground texture applied to it:

function lovr.load()
  texture = lovr.graphics.newTexture('ground.png')
end

function lovr.draw()
  lovr.graphics.plane(texture, 0, 0, 0, 2, 0, 1, 0)
end

For this to work, put an image named ground.png in the same folder that main.lua is in.

Woohoo, let's take this a step further and start drawing 3D Models!

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