// Initialize enough of the opengl context that some OpenGL information
// can be dumped to screen along with the bindings. This is a basic graphics
// package test that checks if the underlying OpenGL functions are available.
// Columns of function names marked [+]:available or [ ]:missing will
// be written the the console.
func dg() {
app := device.New("Dump", 400, 100, 600, 600)
gl.Dump() // gets graphic context to properly bind.
fmt.Printf("%s %s", gl.GetString(gl.RENDERER), gl.GetString(gl.VERSION))
fmt.Printf(" GLSL %s\n", gl.GetString(gl.SHADING_LANGUAGE_VERSION))
app.Dispose()
}
// ld loads a mesh model that has been exported from another tool -
// in this case an .obj file from Blender. It is testing the vu/load package
// with the key line being:
// meshes, _ := ldr.Obj("monkey")
// This example renders using OpenGL from package vu/render/gl.
func ld() {
ld := &ldtag{}
dev := device.New("Load Model", 400, 100, 800, 600)
ld.initScene()
dev.Open()
for dev.IsAlive() {
ld.update(dev)
ld.render()
dev.SwapBuffers()
}
dev.Dispose()
}
// sf demonstrates one example of shader only rendering. This shows the power
// of shaders using an example from shadertoy.com. Specifically:
// https://www.shadertoy.com/view/Xsl3zN
// For more shader examples also check out:
// http://glsl.heroku.com
// The real star of this demo is found in ./source/fire.fsh. Kudos to @301z
// and the other contributors to shadertoy and heroku.
//
// This example renders using OpenGL calls from package vu/render/gl.
func sf() {
sf := new(sftag)
dev := device.New("Shader Fire", 400, 100, 500, 500)
sf.initScene()
dev.Open()
for dev.IsAlive() {
sf.update(dev)
sf.drawScene()
dev.SwapBuffers()
}
dev.Dispose()
}
// tr demonstrates basic OpenGL by drawing a triangle. If anything this example
// shows that basic OpenGL is not all that basic. Check out the following methods:
// • initData() creates a triangle mesh that includes verticies, faces, and colours.
// • initScene() makes the data available to the graphics card.
// • initShader() uses render.BindProgram to load and prepare the shader programs.
// • drawScene() is called to render and spin the triangle.
func tr() {
tag := &trtag{}
dev := device.New("Triangle", 400, 100, 600, 600)
tag.initScene()
dev.Open()
tag.resize(600, 600)
for dev.IsAlive() {
dev.Update()
tag.drawScene()
dev.SwapBuffers()
}
dev.Dispose()
}
// rt helps to understand ray tracing basics. Real time hardware supported ray
// tracing is a possible future rendering alternative. Ray tracing is sufficiently
// different from standard rasterization it would likely need its own 3D engine.
//
// The code in this example is broken into two sections:
// 1. OpenGL based code that displays a single texture on a quad mesh.
// 2. Ray trace code that generates a ray trace image.
//
// Some general ray tracing reading ...
// http://www.ics.uci.edu/~gopi/CS211B/RayTracing%20tutorial.pdf
// http://www.gamasutra.com/blogs/AlexandruVoica/20140318/213148/Practical_techniques_for_ray_tracing_in_games.php?print=1
// http://www.igorsevo.com/Article.aspx?article=A+simple+real-time+raytracer+in+CUDA+and+OpenGL
// http://www.researchgate.net/publication/220183679_OptiX_A_General_Purpose_Ray_Tracing_Engine
func rt() {
rt := new(rtrace)
dev := device.New("Ray Trace", 400, 400, 512, 512)
rt.scene = rt.createScene() // create the scene for the ray tracer.
rt.img = rt.rayTrace() // create the ray traced image.
rt.initRender() // initialize opengl.
dev.Open()
for dev.IsAlive() {
rt.update(dev)
rt.drawScene()
dev.SwapBuffers()
}
dev.Dispose()
}
// sh is used to test and showcase the vu/device package. Just getting a window
// to appear demonstrates that the majority of the functionality is working.
// The remainder of the example dumps keyboard and mouse events showing that
// user input is being processed.
func sh() {
sh := &shtag{}
dev := device.New("Shell", 400, 100, 800, 600)
gl.Init()
fmt.Printf("%s %s", gl.GetString(gl.RENDERER), gl.GetString(gl.VERSION))
fmt.Printf(" GLSL %s\n", gl.GetString(gl.SHADING_LANGUAGE_VERSION))
dev.Open()
gl.ClearColor(0.3, 0.6, 0.4, 1.0)
for dev.IsAlive() {
sh.update(dev)
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
dev.SwapBuffers()
// slow things down so that the loop is closer
// to the engine update loop timing.
time.Sleep(10 * time.Millisecond)
}
dev.ShowCursor(true)
dev.Dispose()
}
// New creates the Engine and initializes the underlying resources needed
// by the engine. It then starts application callbacks through the engine
// App interface. This is expected to be called once on application startup.
func New(app App, name string, wx, wy, ww, wh int) (err error) {
m := &machine{} // main thread and device facing handler.
if app == nil {
return fmt.Errorf("No application. Shutting down.")
}
m.counts = map[uint32]*meshCount{}
// initialize the os specific shell, graphics context, and input tracker.
name, wx, wy, ww, wh = m.vet(name, wx, wy, ww, wh)
m.dev = device.New(name, wx, wy, ww, wh)
// initialize the audio layer.
m.ac = audio.New()
if err = m.ac.Init(); err != nil {
m.shutdown()
return // failed to initialize audio layer
}
// initialize the graphics layer.
m.gc = render.New()
if err = m.gc.Init(); err != nil {
m.shutdown()
return // failed to initialize graphics layer.
}
m.gc.Viewport(ww, wh)
m.dev.Open()
m.input = m.dev.Update()
m.frame1 = []render.Draw{} // Previous render frame.
m.frame0 = []render.Draw{} // Most recent render frame.
// Start the application facing loop for state updates.
// Run the device facing loop for rendering and user input polling.
m.reqs = make(chan msg)
m.stop = make(chan bool)
m.uf = make(chan []render.Draw)
go runEngine(app, wx, wy, ww, wh, m.reqs, m.uf, m.stop)
m.run() // underlying device polling and rendering.
defer m.shutdown() // ensure shutdown happens no matter what.
return nil // report successful termination.
}
