Opengl 2d game code

It is an integral part of all computer user interfaces and is indispensable for visualizing 2D, 3D, and higher-dimensional objects. Creating 3D objects, rotations and any other manipulations is a laborious process with graphics implementation using a text editor. OpenGL provides more features for developing 3D objects with few lines by built-in functions. The geometric objects are the building blocks of any individual.

Thereby developing, manipulating, applying any transformation, rotation, scaling on them is the major task of any image development. Thereby we have put our tiny effort to develop 2D objects and perform different operations on them by using OpenGL utilities.

There aren't many snippets published as snippet, since they're basically useless. Snippets only make sense in presence of a large surrounding network of other snippets. It's much like asking for car parts to construct a car. While technically it's possible, it's not the generally recommended way of doing things.

I somewhat suspect you never programmed before, or at least not a game. If that's the case, you may want to head over to the Beginners forum, and read the FAQ for how to start programming or start programming games. I want to see how other people handled rendering, movement, etc, by putting into practise what I've learning in tutorials I've looked through for OpenGL. You can take a look at the Godot engine. It's only in OpenGL, and it's cross platform compatible.

There's also the Flare game which uses SDL. In the "In Practice" section at learnopengl. You should address the two concerns separately. First you should learn how to draw sprites and text I assume you'll want text in your game.

If you want to use OpenGL then go for it. There are many tutorials online that will help you with that. Creating a game of any kind is a different thing though. My suggestion is you keep your rendering engine abstracted away from the game logic. You can design your RPG without even knowing which library will you end up using to render sprites on screen.

How you implement that interface won't change the design of the rest of the project in any way. That is, display runs when the window first appears and whenever there is a request to re-paint the window. We call the initGL to perform all the one-time initialization operations. In this example, we set the clearing background color once, and use it repeatably in the display function. We then put the program into the event-handling loop, awaiting for events such as window-paint request to trigger off the respective event handlers such as display.

We use glColor function to set the foreground color , and glClearColor function to set the background or clearing color.

In display , we set the vertex color via glColor3f for subsequent vertices. In OpenGL, an object is made up of geometric primitives such as triangle, quad, line segment and point. A primitive is made up of one or more vertices. OpenGL supports the following primitives:. A geometric primitive is defined by specifying its vertices via glVertex function, enclosed within a pair glBegin and glEnd. The vertices are usually specified in float precision.

It is because integer is not suitable for trigonometric operations needed to carry out transformations such as rotation. Precision of float is sufficient for carrying out intermediate operations, and render the objects finally into pixels on screen with resolution of says x, integral precision. All subsequent vertices will have the color of red. Take note that in OpenGL, color and many properties is applied to vertices rather than primitive shapes.

The color of the a primitive shape is interpolated from its vertices. For the third quad as follows , the vertices have different color.

The color of the quad surface is interpolated from its vertices, resulting in a shades of white to dark gray, as shown in the output. The following diagram shows the OpenGL 2D Coordinate System, which corresponds to the everyday 2D Cartesian coordinates with origin located at the bottom-left corner.

The default OpenGL 2D clipping-area i. This clipping-area is mapped to the viewport on the screen. Viewport is measured in pixels. Study the above example to convince yourself that the 2D shapes created are positioned correctly on the screen. Try dragging the corner of the window to make it bigger or smaller.

Observe that all the shapes are distorted. We can handle the re-sizing of window via a callback handler reshape , which can be programmed to adjust the OpenGL clipping-area according to the window's aspect ratio. Clipping Area : Clipping area refers to the area that can be seen i. The function gluOrtho2D can be used to set the clipping area of 2D orthographic view.

Objects outside the clipping area will be clipped away and cannot be seen. To set the clipping area, we need to issue a series of commands as follows: we first select the so-called projection matrix for operation, and reset the projection matrix to identity. We then choose the 2D orthographic view with the desired clipping area, via gluOrtho2D. Viewport : Viewport refers to the display area on the window screen , which is measured in pixels in screen coordinates excluding the title bar.

The clipping area is mapped to the viewport. We can use glViewport function to configure the viewport. Suppose the the clipping area's left, right, bottom, top is It is obvious that if the aspect ratios for the clipping area and the viewport are not the same, the shapes will be distorted.

Related Articles. Table of Contents. Improve Article. Save Article. Like Article. Using this, we can make a lot of design as well as animations. Below is a simple Game made using OpenGL.