What makes your game idea great? For me, this is the most important to write down. But I can give suggestions on what to write about: Others, like me, write a page of badly-written notes, unreadable to anyone else.
Java game dvelopment smart pixel rendering how to#
By Angela He From Zero to Game Designer: how to start building video games even if you don’t have any experienceĢ years ago I was just 17 year old high school student who knew nothing about coding. Let's assume that x is any point contained within the range. We now need to remap the left and right screen coordinates (l, r) to -1 and 1 and do the same for the bottom and right coordinates. We will name these screen coordinates l, r, t, b which stand for left, right, top and bottom. Remember also that the canvas or screen is centred around the screen coordinate system origin (figure 2).įigure 2: setting up the screen coordinates from the scene bounding box.
Java game dvelopment smart pixel rendering code#
You need to potentially extend the projection of the minimum and maximum extents of the bounding box onto the screen in order for the screen window itself to be either square or have the same ratio than the image aspect ratio (check the code of the test program below to see how this can be done). The x- and y-coordinates of any point expressed in camera space and the x- and y-coordinates of the same points projected on the image plane are the same. In the case of an orthographic projection (or parallel projection) this is trivial. Once we have computed the scene bounding box, we need to project the minimum and maximum extents of this bounding box onto the image plane of the camera. All points contained in the scene bounding volume have their projected xy coordinates "normalized" (they lie within the range ). Note that both bounding boxes (the scene bounding box and the canonical view volume) are AABBs (axis-aligned bounding boxes) which simplifies the remapping process a lot.įigure 1: the orthographic projection matrix remaps the scene bounding volume to the canonical view volume. The z-coordinate is remapped to the range (or ). In other words, the x- and y-coordinate of the projected point are remapped from wherever they were before the projection, to the range. This volume is a box which minimum and maximum extents are respectively (-1, -1, -1) and (1, 1, 1) (or (-1,-1,0) and (1,1,1) depending on the convention you are using). Once you have the bounding box for the scene, then the goal of the orthographic matrix is to remap it to a canonical view volume. Very simply, you can loop over all the objects in your scene, compute there bounding box and extent the dimensions of the global bounding box so that it contains all the bounding volumes of these objects.
If you wonder what that original box is, then just imagine that this is a bounding box surrounding all the objects contained in your scene. The goal of this orthographic projection matrix is to actually remap all coordinates contained within a certain bounding box in 3D space into the canonical viewing volume (we introduced this concept already in chapter 2). In this chapter we will learn how to create a matrix that project a point in camera space to a point projected onto the image plane of an orthographic camera.
Orthographic projection can also be used to render shadow maps, or render orthographic views of a 3D model for practical reasons: an architect for example may need to produce blueprints from the 3D model of a house or building designed in a CAD software. Famous games such the Sims or Sim City adopted this look. Why bother then with learning about parallel projection? Images rendered with an orthographic camera can give a certain look to a video game that is better (sometimes) than the more natural look produced with perspective projection. Indeed, what people strive for whether in films or games, is photorealism for which perspective projection is generally used. You might think that orthographic projections are of no use today. The orthographic projection (also sometimes called oblique projection) is simpler than the other type of projections and learning about it is a good way of apprehending how the perspective projection matrix works. Source Code What Do I Need Orthographic Projection For?