// InitGraphics creates an OpenGL window and initializes the required graphics libraries.
// It will either succeed or panic.
func (app *ExampleApp) InitGraphics(title string, w int, h int) {
err := glfw.Init()
if err != nil {
panic("Can't init glfw! " + err.Error())
}
// request a OpenGL 3.3 core context
glfw.WindowHint(glfw.Samples, 0)
glfw.WindowHint(glfw.ContextVersionMajor, 3)
glfw.WindowHint(glfw.ContextVersionMinor, 3)
glfw.WindowHint(glfw.OpenGLForwardCompatible, glfw.True)
glfw.WindowHint(glfw.OpenGLProfile, glfw.OpenGLCoreProfile)
// do the actual window creation
app.MainWindow, err = glfw.CreateWindow(w, h, title, nil, nil)
if err != nil {
panic("Failed to create the main window! " + err.Error())
}
app.MainWindow.MakeContextCurrent()
glfw.SwapInterval(0)
// make sure that all of the GL functions are initialized
err = gl.Init()
if err != nil {
panic("Failed to initialize GL! " + err.Error())
}
// set the app window dimensions
app.Width = w
app.Height = h
gl.FrontFace(gl.CCW)
gl.CullFace(gl.BACK)
gl.Enable(gl.CULL_FACE)
}
//BindForDrawing binds this fbo, change face culling for back face, start using the shadow program, calculate projection and clears the texture.
func (sfbo *ShadowFBO) BindForDrawing() {
sfbo.framebuffer.Bind(gl2.FRAMEBUFFER)
sfbo.program.Use()
sfbo.vp = sfbo.projection.Mul4(sfbo.view)
gl.Clear(gl.DEPTH_BUFFER_BIT | gl.COLOR_BUFFER_BIT)
ViewportChange(sfbo.width, sfbo.height)
gl.CullFace(gl.FRONT)
}
func Init() error {
if err := gl.Init(); err != nil {
return err
}
log.Printf("OpenGL version: %s", gl.GoStr(gl.GetString(gl.VERSION)))
vs, err := asset.String("shader.vert")
if err != nil {
return err
}
fs, err := asset.String("shader.frag")
if err != nil {
return err
}
program, err := createProgram(vs, fs)
if err != nil {
return err
}
gl.UseProgram(program)
var shaderErr error
uniform := func(name string) int32 {
var loc int32
loc, shaderErr = getUniformLocation(program, name)
return loc
}
projectionViewMatrixUniform = uniform("u_projectionViewMatrix")
modelMatrixUniform = uniform("u_modelMatrix")
normalMatrixUniform = uniform("u_normalMatrix")
ambientLightColorUniform = uniform("u_ambientLightColor")
directionalLightColorUniform = uniform("u_directionalLightColor")
directionalVectorUniform = uniform("u_directionalVector")
textureUniform = uniform("u_texture")
grayscaleUniform = uniform("u_grayscale")
brightnessUniform = uniform("u_brightness")
alphaUniform = uniform("u_alpha")
mixColorUniform = uniform("u_mixColor")
mixAmountUniform = uniform("u_mixAmount")
if shaderErr != nil {
return shaderErr
}
vm := newViewMatrix(cameraPosition, targetPosition, up)
nm := vm.inverse().transpose()
gl.UniformMatrix4fv(normalMatrixUniform, 1, false, &nm[0])
gl.Uniform3fv(ambientLightColorUniform, 1, &ambientLightColor[0])
gl.Uniform3fv(directionalLightColorUniform, 1, &directionalLightColor[0])
gl.Uniform3fv(directionalVectorUniform, 1, &directionalVector[0])
SizeCallback = func(width, height int) {
if winWidth == width && winHeight == height {
return
}
log.Printf("window size changed (%dx%d -> %dx%d)", int(winWidth), int(winHeight), width, height)
gl.Viewport(0, 0, int32(width), int32(height))
// Calculate new perspective projection view matrix.
winWidth, winHeight = width, height
fw, fh := float32(width), float32(height)
aspect := fw / fh
fovRadians := float32(math.Pi) / 3
perspectiveProjectionViewMatrix = vm.mult(newPerspectiveMatrix(fovRadians, aspect, 1, 2000))
// Calculate new ortho projection view matrix.
orthoProjectionViewMatrix = newOrthoMatrix(fw, fh, fw /* use width as depth */)
}
if err := initMeshes(); err != nil {
return err
}
if err := initTextures(); err != nil {
return err
}
gl.Enable(gl.CULL_FACE)
gl.CullFace(gl.BACK)
gl.Enable(gl.DEPTH_TEST)
gl.DepthFunc(gl.LESS)
gl.Enable(gl.BLEND)
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
gl.ClearColor(0, 0, 0, 0)
return nil
}
//Unbind return cull face to front and unbind this fbo.
func (sfbo *ShadowFBO) Unbind() {
sfbo.framebuffer.Unbind(gl2.FRAMEBUFFER)
gl.CullFace(gl.BACK)
}
func InitGL() error {
defer tlog.FuncLog(tlog.Func("InitGL"))
err := gl.Init()
if err != nil {
return err
}
gl.GetError() // cleanup gl error state
version := gl.GoStr(gl.GetString(gl.VERSION))
tlog.Println("OpenGL version", version)
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
Check()
gl.ReadBuffer(gl.BACK)
Check()
gl.DrawBuffer(gl.BACK)
Check()
gl.FrontFace(gl.CW)
Check()
gl.CullFace(gl.BACK)
Check()
gl.Disable(gl.CULL_FACE)
Check()
gl.ClearColor(1, 1, 0.5, 0)
Check()
gl.ClearDepth(1.0)
Check()
gl.ClearStencil(0)
Check()
gl.Disable(gl.STENCIL_TEST)
Check()
gl.StencilMask(0xFFFFFFFF)
Check()
gl.StencilFunc(gl.EQUAL, 0x00000000, 0x00000001)
Check()
gl.StencilOp(gl.KEEP, gl.KEEP, gl.KEEP)
Check()
gl.Disable(gl.DITHER)
Check()
gl.Enable(gl.DEPTH_TEST)
Check()
gl.DepthFunc(gl.LEQUAL)
Check()
gl.DepthMask(true)
Check()
gl.DepthRange(0., 1.)
Check()
gl.Enable(gl.DEPTH_CLAMP)
Check()
gl.Enable(gl.BLEND)
Check()
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
ForceCheck()
return nil
}