func createprogram() gl.Uint {
// VERTEX SHADER
vs := gl.CreateShader(gl.VERTEX_SHADER)
vs_source := gl.GLString(vertexShaderSource)
gl.ShaderSource(vs, 1, &vs_source, nil)
gl.CompileShader(vs)
var vs_status gl.Int
gl.GetShaderiv(vs, gl.COMPILE_STATUS, &vs_status)
fmt.Printf("Compiled Vertex Shader: %v\n", vs_status)
// FRAGMENT SHADER
fs := gl.CreateShader(gl.FRAGMENT_SHADER)
fs_source := gl.GLString(fragmentShaderSource)
gl.ShaderSource(fs, 1, &fs_source, nil)
gl.CompileShader(fs)
var fstatus gl.Int
gl.GetShaderiv(fs, gl.COMPILE_STATUS, &fstatus)
fmt.Printf("Compiled Fragment Shader: %v\n", fstatus)
// CREATE PROGRAM
program := gl.CreateProgram()
gl.AttachShader(program, vs)
gl.AttachShader(program, fs)
fragoutstring := gl.GLString("outColor")
defer gl.GLStringFree(fragoutstring)
gl.BindFragDataLocation(program, gl.Uint(0), fragoutstring)
gl.LinkProgram(program)
var linkstatus gl.Int
gl.GetProgramiv(program, gl.LINK_STATUS, &linkstatus)
fmt.Printf("Program Link: %v\n", linkstatus)
return program
}
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 (p *Program) GetUniformLocation(name string) (*UniformLocation, error) {
attributeName := gl.GLString(name)
defer gl.GLStringFree(attributeName)
id := gl.GetUniformLocation(p.id, attributeName)
if id == -1 {
return nil, errors.New(fmt.Sprintf("Could not bind uniform %s\n", gl.GoString(attributeName)))
}
return &UniformLocation{id: id}, nil
}
func (p *Program) GetAttributeLocation(name string) (*AttributeLocation, error) {
attributeName := gl.GLString(name)
defer gl.GLStringFree(attributeName)
attributeTemp := gl.GetAttribLocation(p.id, attributeName)
if attributeTemp == -1 {
return nil, errors.New(fmt.Sprintf("Could not bind attribute %s\n", gl.GoString(attributeName)))
}
return &AttributeLocation{id: gl.Uint(attributeTemp)}, nil
}
func initResources() {
var compileOk gl.Int
// Vertex Shader
vs = gl.CreateShader(gl.VERTEX_SHADER)
vsSrc := gl.GLStringArray(vsSource)
defer gl.GLStringArrayFree(vsSrc)
gl.ShaderSource(vs, gl.Sizei(len(vsSrc)), &vsSrc[0], nil)
gl.CompileShader(vs)
gl.GetShaderiv(vs, gl.COMPILE_STATUS, &compileOk)
if compileOk == 0 {
errNum := gl.GetError()
fmt.Printf("Error in vertex shader: %d\n", errNum)
}
// Fragment Shader
fs = gl.CreateShader(gl.FRAGMENT_SHADER)
fsSrc := gl.GLStringArray(fsSource)
defer gl.GLStringArrayFree(fsSrc)
gl.ShaderSource(fs, gl.Sizei(1), &fsSrc[0], nil)
gl.CompileShader(fs)
gl.GetShaderiv(fs, gl.COMPILE_STATUS, &compileOk)
if compileOk == 0 {
errNum := gl.GetError()
fmt.Printf("Error in fragment shader: %d\n", errNum)
}
// GLSL program
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")
}
// 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)
}
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 (shader *Shader) Source(source string) {
str := gl33.GLString(source)
defer gl33.GLStringFree(str)
length := gl33.Int(len(source))
gl33.ShaderSource(shader.Id, 1, &str, &length)
}