![]() We've used what's called c olumn notation to describe this vector, but row notation works just as well. Notice how the blue arrow starts at one location (in this case, the origin) and stretches out to the vertex. Vertices are actually described using vectors, based on the Cartesian coordinates, in this manner: Rather than simply change the coordinates, the vast majority of 3D graphics rendering systems use a specific mathematical tool to get the job done: we're talking about vectors.Ī vector can be thought of as an arrow that points towards a particular location in space and can be of any length required. You'd naturally expect the ( x, y, z) numbers for each vertex to change accordingly and they are however, how this is done may seem a little unusual. Imagine you have a triangle on the screen and you push a key to move it to the left. Ready for some math? Good! Because this is how these things get done. Put simply, one or two of things are done to them: Microsoft provides a quick introduction to the use of this buffer in their online documents resource.įor now, let's concentrate on what gets done to these vertices in a 3D game, every time a new frame is rendered (if you're not sure what that means, have a quick scan again of our rendering 101). an in-game NPC model, then it's best to use something called a mesh - this is another block of memory but it consists multiple buffers (vertex, index, etc) and the texture resources for the model. If you want to handle a larger collection of vertices, e.g. In the example below, we can see that only 4 vertices are needed to make 2 triangles joined together - if they were separate, we'd need 6 vertices.įrom left to right: a point list, a line list, and a triangle strip Used correctly, triangle strips use vertices for more than one triangle, helping to boost performance. In the case of the former, the different shapes that can be formed from the vertices are called primitives and Direct3D offers list, strips, and fans in the form of points, lines, and triangles. All of the vertex data is stored in a contiguous block of memory called a vertex buffer the information about the shape they will make is either directly coded into the rendering programme or stored in another block of memory called an index buffer. Note that the lines shown aren't really necessary - we can just have the points and tell the system that these 3 vertices make a triangle. This is commonly written in the form of 3 values together, for example (1, 8, -3), or more generally ( x, y, z).įrom here, we can add in two more vertices to get a triangle: Since we're based in a 3D geometrical world, we use the Cartesian coordinate system for the points. The proper name for a corner is a vertex (vertices being the plural word) and each one is described by a point. The name triangle tells us that the shape has 3 interior angles to have this, we need 3 corners and 3 lines joining the corners together. There are significant performance gains to be made by working on groups of points together, especially in the form of triangles, so let's begin a closer look with these. ![]() Some of these calculations are very quick and easy to do others are much harder. Some are just a handful of lines, such as the rocks in the foreground, whereas others have so many lines that they appear solid.Įvery point at the start and end of each line has been processed by doing a whole bunch of math. Set like this, the 3D rendering engine skips textures and effects done in the pixel stage, and draws nothing but the colored lines connecting the points together.Įverything looks very different now, but we can see all of the lines that go together to make up the various objects, environment, and background. It might be a bit hard to see how this is all just a big pile of points and lines, so we'll show you how the same scene looks in 'wireframe' mode. The image below is a screenshot from Bethesda's 2015 release Fallout 4: There's nothing smaller than a point, as it has no size, so they can be used to clearly define where objects such as lines, planes, and volumes start and end.įor 3D graphics, this information is crucial for setting out how everything will look because everything displayed is a collection of lines, planes, etc. ![]() In the world of math, a point is simply a location within a geometric space. ![]() SSAA, MSAA, FXAA, TAA, and Others What's the point? The Math of Lighting, SSR, Ambient Occlusion, Shadow Mapping Part 4: 3D Game Rendering: Lighting and Shadows Part 2: 3D Game Rendering: Rasterization and Ray Tracingīilinear, Trilinear, Anisotropic Filtering, Bump Mapping, More Part 1: 3D Game Rendering: Vertex ProcessingĪ Deeper Dive Into the World of 3D Graphics
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