SDL2.swift

Work-in-progress SDL2 bindings for Swift.

Usage notes

When first compiling a project that uses this package, the build will probably fail. To fix, run these commands:

$ cd Packages/SDL2.swift-*
$ ./Hooks/post-install

This step is required because SDL uses enum and integers interchangably; as far as I can tell this isn't compatible with Swift's C interop. As a workaround, constants.swift is generated which defines suitably-typed integers for all SDL constants.

If SDL's prefix is not /usr you will need to update support/sdl2-prefix before running the post install script.

If the post install script fails you may need to update the configuration options in support/gen.rb.

Example

Hello Triangle (requires OpenGL support, via JFOpenGL)

import SDL2
import JFOpenGL

sdl.start()
defer { sdl.quit() }

let window = Window(title: "Hello world!", width: 800, height: 600, flags: WindowFlags.OPENGL)

let gl = sdl.gl.createContext(window: window)!
defer { sdl.gl.delete(context: gl) }

let vertexShader = "" +
	"attribute vec3 vp;" +
	"void main() {" +
	"  gl_Position = vec4(vp, 1.0);" +
	"}";

let fragmentShader = "" +
	"void main() {\n" +
	"  gl_FragColor = vec4(0.5, 0.0, 0.5, 1.0);\n" +
	"}";

let points : [GLfloat] = [
	0.0,  0.5,  0.0,
   	0.5, -0.5,  0.0,
   -0.5, -0.5,  0.0
]

var success : GLint = 0

var vbo : GLuint = 0
glGenBuffers(1, &vbo)
glBindBuffer(GL_ARRAY_BUFFER, vbo)
glBufferData(GL_ARRAY_BUFFER, 9 * MemoryLayout<GLfloat>.size, points, GL_STATIC_DRAW);

var vao : GLuint = 0
glGenVertexArrays(1, &vao)
glBindVertexArray(vao)
glEnableVertexAttribArray(0)
glBindBuffer(GL_ARRAY_BUFFER, vbo)
glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, nil);

let vs = glCreateShader(GL_VERTEX_SHADER)
print(vertexShader)
glShaderSource(vs, vertexShader)
glCompileShader(vs)
glGetShaderiv(vs, GL_COMPILE_STATUS, &success)
print(success == GL_FALSE)

let fs = glCreateShader(GL_FRAGMENT_SHADER)
print(fragmentShader)
glShaderSource(fs, fragmentShader)
glCompileShader(fs)
glGetShaderiv(fs, GL_COMPILE_STATUS, &success)
print(success == GL_FALSE)

let prog = glCreateProgram()
glAttachShader(prog, fs)
glAttachShader(prog, vs)
glLinkProgram(prog)

glClearColor(1.0, 0.3, 0.1, 0)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glUseProgram(prog)
glBindVertexArray(vao)
glDrawArrays(GL_TRIANGLES, 0, 3)

sdl.gl.swap(window: window)

var evt = Event()

while true {
	Events.wait(evt: &evt)
	if evt.isQuit {
		break
	}
}

Audio Example

440Hz sine wave in stereo on the default audio device:

#if os(OSX) || os(iOS)
import Darwin
#elseif os(Linux)
import Glibc
#endif

sdl.start()
defer { sdl.quit() }

var spec : AudioSpec = AudioSpec()
spec.frequency = 44100
spec.channels = 2
spec.samples = 4096
spec.format = AudioFormat.F32.rawValue

var sample = 0
spec.setCallback() { (_, buf: UnsafeMutableBufferPointer<Float>) in
	for i in stride(from: 0, to: buf.count, by: 2) {
		let ix = (Float(sample) / 44100.0) * Float(M_PI) * 2.0
		let val = sin(ix * 440.0) * 0.7
		buf[i] = val
		buf[i+1] = val
		sample += 1
	}
}

let audioDevice = sdl.audio.openDefaultPlaybackDevice(spec: spec)!
audioDevice.resume()

sdl.waitForQuit()