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 (p *Program) Link() error {
linkOk := gl.Int(gl.FALSE)
gl.LinkProgram(p.id)
gl.GetProgramiv(p.id, gl.LINK_STATUS, &linkOk)
if linkOk == gl.FALSE {
return p.getError()
}
return nil
}
func (p *Program) getError() error {
var logLength gl.Int
gl.GetProgramiv(p.id, gl.INFO_LOG_LENGTH, &logLength)
log := gl.GLStringAlloc(gl.Sizei(logLength))
defer gl.GLStringFree(log)
gl.GetProgramInfoLog(p.id, gl.Sizei(logLength), nil, log)
err := gl.GoString(log)
return errors.New(err)
}
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 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)
}