func NewProgram(vertexShaderSource, fragmentShaderSource string) (uint32, error) {
vertexShader, err := compileShader(vertexShaderSource, gl.VERTEX_SHADER)
if err != nil {
return 0, err
}
fragmentShader, err := compileShader(fragmentShaderSource, gl.FRAGMENT_SHADER)
if err != nil {
return 0, err
}
program := gl.CreateProgram()
gl.AttachShader(program, vertexShader)
gl.AttachShader(program, fragmentShader)
gl.LinkProgram(program)
var status int32
gl.GetProgramiv(program, gl.LINK_STATUS, &status)
if status == gl.FALSE {
var logLength int32
gl.GetProgramiv(program, gl.INFO_LOG_LENGTH, &logLength)
log := strings.Repeat("\x00", int(logLength+1))
gl.GetProgramInfoLog(program, logLength, nil, gl.Str(log))
gl.DeleteProgram(program)
gl.DeleteShader(vertexShader)
gl.DeleteShader(fragmentShader)
return 0, errors.New(fmt.Sprintf("failed to link program: %v", log))
}
gl.DetachShader(program, vertexShader)
gl.DetachShader(program, fragmentShader)
gl.DeleteShader(vertexShader)
gl.DeleteShader(fragmentShader)
return program, nil
}
// Destroying a ShaderProgram.
func DestroyShaderProgram(shaderProgram ShaderProgram) {
gl.DeleteProgram(uint32(shaderProgram))
}
func InitShader(shader graphics.ShaderSource) (uint32, error) {
//vertexshader
vertexShaderHandle := gl.CreateShader(gl.VERTEX_SHADER)
defer gl.DeleteShader(vertexShaderHandle)
vertText := gl.Str(shader.GetVertexSource())
gl.ShaderSource(vertexShaderHandle, 1, &vertText, nil)
gl.CompileShader(vertexShaderHandle)
//error handling
var isVertexCompiled int32
gl.GetShaderiv(vertexShaderHandle, gl.COMPILE_STATUS, &isVertexCompiled)
if isVertexCompiled == gl.FALSE {
var maxLength int32
gl.GetShaderiv(vertexShaderHandle, gl.INFO_LOG_LENGTH, &maxLength)
log := strings.Repeat("\x00", int(maxLength+1))
gl.GetShaderInfoLog(vertexShaderHandle, maxLength, nil, gl.Str(log))
gl.DeleteShader(vertexShaderHandle)
fmt.Println("Vertex shader compile error")
fmt.Println(log)
return 0, errors.New("Vertex shader compile error")
}
//fragment shader
fragmentShaderHandle := gl.CreateShader(gl.FRAGMENT_SHADER)
defer gl.DeleteShader(fragmentShaderHandle)
fragText := gl.Str(shader.GetFragmentSource())
gl.ShaderSource(fragmentShaderHandle, 1, &fragText, nil)
gl.CompileShader(fragmentShaderHandle)
//error handling
var isFragmentCompiled int32
gl.GetShaderiv(fragmentShaderHandle, gl.COMPILE_STATUS, &isFragmentCompiled)
if isFragmentCompiled == gl.FALSE {
var maxLength int32
gl.GetShaderiv(fragmentShaderHandle, gl.INFO_LOG_LENGTH, &maxLength)
log := strings.Repeat("\x00", int(maxLength+1))
gl.GetShaderInfoLog(fragmentShaderHandle, maxLength, nil, gl.Str(log))
gl.DeleteShader(fragmentShaderHandle)
fmt.Println("Fragment shader compile error")
fmt.Println(log)
return 0, errors.New("Fragment shader compile error")
}
//program shader
shaderHandle := gl.CreateProgram()
gl.AttachShader(shaderHandle, vertexShaderHandle)
gl.AttachShader(shaderHandle, fragmentShaderHandle)
gl.LinkProgram(shaderHandle)
//error handling
var isLinked int32
gl.GetProgramiv(shaderHandle, gl.LINK_STATUS, &isLinked)
if isLinked == gl.FALSE {
var maxLength int32
gl.GetProgramiv(shaderHandle, gl.INFO_LOG_LENGTH, &maxLength)
log := strings.Repeat("\x00", int(maxLength+1))
gl.GetProgramInfoLog(shaderHandle, maxLength, nil, gl.Str(log))
gl.DeleteProgram(shaderHandle)
fmt.Println("Shader linking error")
fmt.Println(log)
return 0, errors.New("Shader linking error")
}
return shaderHandle, nil
}
//Delete is the implementation of the opengl object interface. Delete this object
//from the opengl context
func (shader BlankShader) Delete() {
gl.DeleteProgram(shader.Handle)
}
func (p *Program) Delete() {
gl.DeleteVertexArrays(1, &p.vao)
p.vao = 0
gl.DeleteProgram(p.program)
p.program = 0
}