Easy 3D camera management

SceneCamera manages the camera for 3D applications. It provides the V, in the GL trinity MVP. And if needed, the P as well.

It comes with 3 convenient modes, museum mode, first person mode, and RTS (Real Time Strategy) mode.

It is designed to work with OpenGL, but does not rely on any graphics libraries (just a matrix lib). It could be used with other graphics libraries, but you may have to copy the matrices into your graphics library's matrix format.

An example program is included in the examples directory. It can be run with

cd examples go run . 

Museum mode is a simple camera that orbits around a point, and can zoom in and out. Draw your object at the origin, and the camera will orbit around it. It is useful for inspecting 3D models from all angles.

The classic game mode. Move forwards, backwards, strafe and turn. It can also pitch, roll, and yaw, making it useful for flight simulators.

The camera floats over a ground plane. Forwards, backwards and strafe slide the camera along the ground plane. It can also spin around a point on the the map, using the pitch and yaw.

SceneCamera provides the correct matrices for rendering in SBS (or twin display) mode. Rather than taking control of the render like many graphics libraries, sceneCamera just hands you the matrices so that you can use them in your own render. See the example directory for more details.

a quick summary:

func RenderStereoFrame(state *State) { // Set the inter-pupilary distance. Not critical, but the wrong value will make you feel sick.	camera.SetIPD(2.0)	//get window width and height	width, height := MainWin.GetSize()	camera.Screenwidth = float32(width)/2	camera.Screenheight = float32(height) //Get the view matrix for the left eye	LeftviewMatrix := camera.LeftEyeViewMatrix() //Get the projection matrix for the left eye	LeftEyeFrustrum := camera.LeftEyeFrustrum()	// Set the viewport to left half of the window	gl.Viewport(0, 0, int32(width/2), int32(height)) //Render the scene to the left eye	RenderFrame(state, LeftviewMatrix, LeftEyeFrustrum) //Get the matrices for the right eye	viewMatrix := camera.RightEyeViewMatrix()	RightProjectionMatrix := camera.RightEyeFrustrum() //Set the viewport to right half of the window	gl.Viewport(int32(width/2), 0, int32(width/2), int32(height)) Draw the scene to the right eye display	RenderFrame(state, viewMatrix, RightProjectionMatrix)	//Set viewport to whole window	gl.Viewport(0, 0, int32(width), int32(height)) } 

The camera starts at z=5 (0,0,5), looking at the origin(0,0,0). Positive Y is up (0,1,0).

In RTS mode, the camera starts at (10,10,10), looking at the origin(0,0,0). Positive Z is up (0,0,1). The ground plane is at z=0, covering the x and y axes. i.e. the ground normal vector is (0,0,1).

All these settings can be changed by setting the appropriate field.

import "github.com/donomii/sceneCamera" //Create a new camera camera := sceneCamera.New(2) //FPS mode camera.Move(0,0.5) //Move forwards 0.5 world units viewMatrix := camera.ViewMatrix() //Get the view matrix for the camera cameraUniform := gl.GetUniformLocation(state.Program, gl.Str("camera\x00")) gl.UniformMatrix4fv(cameraUniform, 1, false, &viewMatrix[0]) // Draw your scene