Starting work on Engine+Mesh+Material systems/packages

engine/engine.go

@@ -0,0 +1,108 @@
+package engine
+
+import (
+	"github.com/bloeys/nmage/timing"
+	"github.com/go-gl/gl/v4.1-core/gl"
+	"github.com/veandco/go-sdl2/sdl"
+)
+
+type Window struct {
+	SDLWin *sdl.Window
+	GlCtx  sdl.GLContext
+}
+
+func (w *Window) Destroy() error {
+	return w.SDLWin.Destroy()
+}
+
+func Init() error {
+
+	timing.Init()
+	err := initSDL()
+
+	return err
+}
+
+func initSDL() error {
+
+	err := sdl.Init(sdl.INIT_EVERYTHING)
+	if err != nil {
+		return err
+	}
+
+	sdl.ShowCursor(1)
+
+	sdl.GLSetAttribute(sdl.MAJOR_VERSION, 4)
+	sdl.GLSetAttribute(sdl.MINOR_VERSION, 1)
+
+	// R(0-255) G(0-255) B(0-255)
+	sdl.GLSetAttribute(sdl.GL_RED_SIZE, 8)
+	sdl.GLSetAttribute(sdl.GL_GREEN_SIZE, 8)
+	sdl.GLSetAttribute(sdl.GL_BLUE_SIZE, 8)
+
+	sdl.GLSetAttribute(sdl.GL_DOUBLEBUFFER, 1)
+	sdl.GLSetAttribute(sdl.GL_DEPTH_SIZE, 24)
+	sdl.GLSetAttribute(sdl.GL_STENCIL_SIZE, 8)
+
+	sdl.GLSetAttribute(sdl.GL_CONTEXT_PROFILE_MASK, sdl.GL_CONTEXT_PROFILE_CORE)
+
+	return nil
+}
+
+func CreateOpenGLWindow(title string, x, y, width, height int32, flags WindowFlags) (*Window, error) {
+	return createWindow(title, x, y, width, height, WindowFlags_OPENGL|flags)
+}
+
+func CreateOpenGLWindowCentered(title string, width, height int32, flags WindowFlags) (*Window, error) {
+	return createWindow(title, -1, -1, width, height, WindowFlags_OPENGL|flags)
+}
+
+func createWindow(title string, x, y, width, height int32, flags WindowFlags) (*Window, error) {
+
+	if x == -1 && y == -1 {
+		x = sdl.WINDOWPOS_CENTERED
+		y = sdl.WINDOWPOS_CENTERED
+	}
+
+	sdlWin, err := sdl.CreateWindow(title, x, y, width, height, uint32(flags))
+	if err != nil {
+		return nil, err
+	}
+	win := &Window{SDLWin: sdlWin}
+
+	win.GlCtx, err = sdlWin.GLCreateContext()
+	if err != nil {
+		return nil, err
+	}
+
+	err = initOpenGL()
+	if err != nil {
+		return nil, err
+	}
+
+	return win, err
+}
+
+func initOpenGL() error {
+
+	if err := gl.Init(); err != nil {
+		return err
+	}
+
+	gl.Enable(gl.DEPTH_TEST)
+
+	gl.Enable(gl.CULL_FACE)
+	gl.CullFace(gl.BACK)
+	gl.FrontFace(gl.CCW)
+
+	gl.ClearColor(0, 0, 0, 1)
+	return nil
+}
+
+func SetVSync(enabled bool) {
+	if enabled {
+		sdl.GLSetSwapInterval(1)
+	} else {
+		sdl.GLSetSwapInterval(0)
+	}
+}