func display() {
// Clear the background as white
gl.ClearColor(1.0, 1.0, 1.0, 1.0)
gl.Clear(gl.COLOR_BUFFER_BIT)
// Use the GLSL program
gl.UseProgram(program)
gl.BindBuffer(gl.ARRAY_BUFFER, vboTriangle)
gl.EnableVertexAttribArray(attributeCoord2d)
// Describe our vertices array to OpenGL (it can't guess its format automatically)
gl.VertexAttribPointer(attributeCoord2d, 2, gl.FLOAT, gl.FALSE, 0, gl.Pointer(nil))
gl.EnableVertexAttribArray(attributeColor)
gl.BindBuffer(gl.ARRAY_BUFFER, vboTriangleColors)
gl.VertexAttribPointer(attributeColor, 3, gl.FLOAT, gl.FALSE, 0, gl.Pointer(nil))
// Push each element in buffer_vertices to the vertex shader
gl.DrawArrays(gl.TRIANGLES, 0, 3)
gl.DisableVertexAttribArray(attributeCoord2d)
gl.DisableVertexAttribArray(attributeColor)
gl.BindBuffer(gl.ARRAY_BUFFER, 0) // Unbind
// Display the result
glfw.SwapBuffers()
}
func initResources() {
var err error
// Load shaders
vs, err = createShader("triangle.v.glsl", VertexShaderType)
if err != nil {
fmt.Printf("Shader: %s\n", err)
return
}
fs, err = createShader("triangle.f.glsl", FragmentShaderType)
if err != nil {
fmt.Printf("Shader: %s\n", err)
return
}
// Create GLSL program with loaded shaders
var compileOk gl.Int
program = gl.CreateProgram()
gl.AttachShader(program, vs)
gl.AttachShader(program, fs)
gl.LinkProgram(program)
gl.GetProgramiv(program, gl.LINK_STATUS, &compileOk)
if compileOk == 0 {
fmt.Printf("Error in program.\n")
}
// Generate a buffer for the VertexBufferObject
gl.GenBuffers(1, &vboTriangle)
gl.BindBuffer(gl.ARRAY_BUFFER, vboTriangle)
// Submit the vertices of the triangle to the graphic card
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(len(triangleVertices)*4), gl.Pointer(&triangleVertices[0]), gl.STATIC_DRAW)
// Unset the active buffer
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
// Generate a buffer for the Color-VBO
gl.GenBuffers(1, &vboTriangleColors)
gl.BindBuffer(gl.ARRAY_BUFFER, vboTriangleColors)
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(len(triangleColors)*4), gl.Pointer(&triangleColors[0]), gl.STATIC_DRAW)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
// Get the attribute location from the GLSL program (here from the vertex shader)
attributeName := gl.GLString("coord2d")
defer gl.GLStringFree(attributeName)
attributeTemp := gl.GetAttribLocation(program, attributeName)
if attributeTemp == -1 {
fmt.Printf("Could not bind attribute %s\n", gl.GoString(attributeName))
}
attributeCoord2d = gl.Uint(attributeTemp)
attributeName = gl.GLString("v_color")
defer gl.GLStringFree(attributeName)
attributeTemp = gl.GetAttribLocation(program, attributeName)
if attributeTemp == -1 {
fmt.Printf("Could not bind attribute %s\n", gl.GoString(attributeName))
}
attributeColor = gl.Uint(attributeTemp)
}
func drawPrimitives(color color.Color, mode gl.Enum, vecs ...geometry.Vector2) {
vertices := make([]float32, len(vecs)*2)
r, g, b, a := glcolor.ConvertColorF(color)
var colors []float32
for i := range vecs {
vertices[i*2] = vecs[i].X
vertices[i*2+1] = vecs[i].Y
colors = append(colors, r, g, b, a)
}
DefaultPrimitivesShaderProgram.Use()
primitivesUniformMatrix.UniformMatrix4fv(1, false, DefaultCamera.Transposed())
primitivesAttributeCoord.Enable()
primitivesAttributeCoord.AttribPointer(2, gl.FLOAT, false, 0, gl.Pointer(&vertices[0]))
primitivesAttributeColor.Enable()
primitivesAttributeColor.AttribPointer(4, gl.FLOAT, false, 0, gl.Pointer(&colors[0]))
gl.DrawArrays(mode, 0, gl.Sizei(len(vecs)))
primitivesAttributeColor.Disable()
primitivesAttributeCoord.Disable()
}
func (buffer *Buffer) Update() {
buffer.Bind()
data := gl33.Pointer(buffer.Value.Pointer())
size := gl33.Sizeiptr(buffer.Value.Len() * int(buffer.Value.Type().Elem().Size()))
gl33.BufferData(buffer.Target, size, data, buffer.Type)
}
func (vbo *VertexBufferObject) BufferData(data []float32) {
gl.BindBuffer(gl.ARRAY_BUFFER, vbo.id)
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(len(data)*4), gl.Pointer(&data[0]), gl.STATIC_DRAW)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
}
func main() {
var window *sdl.Window
var context sdl.GLContext
var event sdl.Event
var running bool
var err error
runtime.LockOSThread()
if err = sdl.Init(sdl.INIT_EVERYTHING); err != nil {
panic(err)
}
defer sdl.Quit()
window, err = sdl.CreateWindow(winTitle, sdl.WINDOWPOS_UNDEFINED,
sdl.WINDOWPOS_UNDEFINED,
winWidth, winHeight, sdl.WINDOW_OPENGL)
if err != nil {
panic(err)
}
defer window.Destroy()
context, err = sdl.GL_CreateContext(window)
if err != nil {
panic(err)
}
defer sdl.GL_DeleteContext(context)
gl.Init()
gl.Viewport(0, 0, gl.Sizei(winWidth), gl.Sizei(winHeight))
// OPENGL FLAGS
gl.ClearColor(0.0, 0.1, 0.0, 1.0)
gl.Enable(gl.DEPTH_TEST)
gl.DepthFunc(gl.LESS)
gl.Enable(gl.BLEND)
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
// VERTEX BUFFER
var vertexbuffer gl.Uint
gl.GenBuffers(1, &vertexbuffer)
gl.BindBuffer(gl.ARRAY_BUFFER, vertexbuffer)
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(len(triangle_vertices)*4), gl.Pointer(&triangle_vertices[0]), gl.STATIC_DRAW)
// COLOUR BUFFER
var colourbuffer gl.Uint
gl.GenBuffers(1, &colourbuffer)
gl.BindBuffer(gl.ARRAY_BUFFER, colourbuffer)
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(len(triangle_colours)*4), gl.Pointer(&triangle_colours[0]), gl.STATIC_DRAW)
// GUESS WHAT
program := createprogram()
// VERTEX ARRAY
var VertexArrayID gl.Uint
gl.GenVertexArrays(1, &VertexArrayID)
gl.BindVertexArray(VertexArrayID)
gl.EnableVertexAttribArray(0)
gl.BindBuffer(gl.ARRAY_BUFFER, vertexbuffer)
gl.VertexAttribPointer(0, 3, gl.FLOAT, gl.FALSE, 0, nil)
// VERTEX ARRAY HOOK COLOURS
gl.EnableVertexAttribArray(1)
gl.BindBuffer(gl.ARRAY_BUFFER, colourbuffer)
gl.VertexAttribPointer(1, 3, gl.FLOAT, gl.FALSE, 0, nil)
//UNIFORM HOOK
unistring := gl.GLString("scaleMove")
UniScale = gl.GetUniformLocation(program, unistring)
fmt.Printf("Uniform Link: %v\n", UniScale+1)
gl.UseProgram(program)
running = true
for running {
for event = sdl.PollEvent(); event != nil; event =
sdl.PollEvent() {
switch t := event.(type) {
case *sdl.QuitEvent:
running = false
case *sdl.MouseMotionEvent:
xrot = float32(t.Y) / 2
yrot = float32(t.X) / 2
fmt.Printf("[%dms]MouseMotion\tid:%d\tx:%d\ty:%d\txrel:%d\tyrel:%d\n", t.Timestamp, t.Which, t.X, t.Y, t.XRel, t.YRel)
}
}
drawgl()
sdl.GL_SwapWindow(window)
}
}
func LoadTextureArray(filenames []string, minFilter int, magFilter int) *Texture {
ch := make(chan *Texture)
GL <- func() {
tex := NewTextureArray()
tex.SetFilters(minFilter, magFilter)
tex.Bind(0)
surfaces := make([]*sdl.Surface, len(filenames))
for i, filename := range filenames {
surfaces[i] = sdl.Load(filename)
if surfaces[i] == nil {
panic(sdl.GetError())
}
defer surfaces[i].Free()
}
tex.Width = int(surfaces[0].W)
tex.Height = int(surfaces[0].H)
var internalFormat gl33.Int
var format gl33.Enum
var size int
if surfaces[0].Format.BitsPerPixel == 32 {
internalFormat = gl33.RGBA8
format = gl33.RGBA
size = 4
} else {
internalFormat = gl33.RGB8
format = gl33.RGB
size = 3
}
pixels := make([]byte, tex.Width*tex.Height*len(surfaces)*size)
for i, surface := range surfaces {
p := uintptr(surface.Pixels)
for j := 0; j < tex.Width*tex.Height*size; j++ {
pixels[i*tex.Width*tex.Height*size+j] = *(*byte)(unsafe.Pointer(p + uintptr(j)))
}
}
gl33.TexImage3D(gl33.TEXTURE_2D_ARRAY, 0, internalFormat, gl33.Sizei(tex.Width), gl33.Sizei(tex.Height), gl33.Sizei(len(surfaces)), 0, format, gl33.UNSIGNED_BYTE, gl33.Pointer(&pixels[0]))
gl33.GenerateMipmap(gl33.TEXTURE_2D_ARRAY)
ch <- tex
}
return <-ch
}
func uploadSurface(target gl33.Enum, surface *sdl.Surface) {
if target == gl33.TEXTURE_CUBE_MAP && surface.W != surface.H {
panic("Non-square texture in cube map")
}
var internalFormat gl33.Int
var format gl33.Enum
if surface.Format.BitsPerPixel == 32 {
internalFormat = gl33.RGBA8
format = gl33.RGBA
} else {
internalFormat = gl33.RGB8
format = gl33.RGB
}
gl33.TexImage2D(target, 0, internalFormat, gl33.Sizei(surface.W), gl33.Sizei(surface.H), 0, format, gl33.UNSIGNED_BYTE, gl33.Pointer(surface.Pixels))
}
func setupAttrib(location gl33.Uint, type_ gl33.Enum, dimensions int, offset uintptr, vertexSize int) {
gl33.EnableVertexAttribArray(location)
if type_ == gl33.FLOAT || type_ == gl33.DOUBLE {
gl33.VertexAttribPointer(location, gl33.Int(dimensions), type_, gl33.FALSE, gl33.Sizei(vertexSize), gl33.Pointer(offset))
} else {
gl33.VertexAttribIPointer(location, gl33.Int(dimensions), type_, gl33.Sizei(vertexSize), gl33.Pointer(offset))
}
}
func (mesh *Mesh) Render() {
gl33.BindVertexArray(mesh.vao)
gl33.DrawElements(gl33.TRIANGLES, gl33.Sizei(len(mesh.Indicies)), gl33.UNSIGNED_INT, gl33.Pointer(uintptr(0)))
}
// LoadTexture buffers an image.Image into the graphic cards memory.
func LoadTexture(img image.Image) (*Texture, error) {
w := img.Bounds().Dx()
h := img.Bounds().Dy()
rgba := image.NewRGBA(image.Rect(0, 0, w, h))
for x := 0; x < w; x++ {
for y := 0; y < h; y++ {
rgba.Set(x, y, img.At(x, y))
}
}
var textureId gl.Uint
//gl.ActiveTexture(gl.TEXTURE0)
gl.GenTextures(1, &textureId)
gl.BindTexture(gl.TEXTURE_2D, textureId)
//gl.TexParameterf(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameterf(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexImage2D(gl.TEXTURE_2D, 0, 4, gl.Sizei(rgba.Rect.Dx()), gl.Sizei(rgba.Rect.Dy()), 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.Pointer(&rgba.Pix[0]))
gl.BindTexture(gl.TEXTURE_2D, 0)
return &Texture{id: textureId}, nil
}