Openlierox sprites code#

Note that we store both the position and texture-coordinate data in a single vec4 variable. Gl_Position = projection * model * vec4(vertex.xy, 0.0, 1.0) To transform a sprite, we use the following vertex shader: Using the projection matrix we can directly transform the world-space coordinates to normalized device coordinates. Since Breakout is a single-scene game, there is no need for a view/camera matrix. We create a textured quad that we can transform with a model matrix, after which we project it using the previously defined orthographic projection matrix. Rendering an actual sprite shouldn't be too complicated. This allows us to specify all vertex coordinates equal to the pixel coordinates they end up in on the screen, which is rather intuitive for 2D games. The result is that the top-left coordinate of the scene will be at ( 0,0) and the bottom-right part of the screen is at coordinate ( 800,600), just like screen coordinates the world-space coordinates directly correspond to the resulting pixel coordinates. Here we specified that the top of the frustum has a y coordinate of 0, while the bottom has a y coordinate of 600. This projection matrix transforms all x coordinates between 0 and 800 to -1 and 1, and all y coordinates between 0 and 600 to -1 and 1. The first four arguments specify in order the left, right, bottom, and top part of the projection frustum. Because an orthographic projection matrix directly transforms all coordinates to normalized device coordinates, we can choose to specify the world coordinates as screen coordinates by defining the projection matrix as follows: We don't need any perspective applied to the coordinates, since the game is entirely in 2D, so an orthographic projection matrix would suit the rendering quite well. By generating the appropriate projection matrix we can work with different coordinates that are easier to work with, compared to directly specifying all coordinates as normalized device coordinates. We know from the coordinate systems chapter that a projection matrix converts all view-space coordinates to clip-space (and then to normalized device) coordinates. First, we have to set up a proper projection matrix though.

Openlierox sprites code#

This way, we're abstracting the gameplay code from the gritty OpenGL rendering code as is commonly done in larger projects. In this chapter we'll define a rendering class that allows us to render a large amount of unique sprites with a minimal amount of code. If we were to manually define these shapes and transformations for each object, it'll quickly get messy. However, in a larger application like this we rather have some abstractions on rendering 2D shapes. We can, just like we did in previous chapters, create a 2D shape out of vertex data, pass all data to the GPU, and transform it all by hand.

Basically, sprites are the render-able image/texture objects we use in a 2D game. A sprite has many definitions, but it's effectively not much more than a 2D image used together with some data to position it in a larger world (e.g. To bring some life to the currently black abyss of our game world, we will render sprites to fill the void. Rendering Sprites In-Practice/2D-Game/Rendering-Sprites