// CreateProgram creates, compiles, and links a gl.Program.
func CreateProgram(vertexSrc, fragmentSrc string) (gl.Program, error) {
program := gl.CreateProgram()
if program.Value == 0 {
return gl.Program{}, fmt.Errorf("glutil: no programs available")
}
vertexShader, err := loadShader(gl.VERTEX_SHADER, vertexSrc)
if err != nil {
return gl.Program{}, err
}
fragmentShader, err := loadShader(gl.FRAGMENT_SHADER, fragmentSrc)
if err != nil {
gl.DeleteShader(vertexShader)
return gl.Program{}, err
}
gl.AttachShader(program, vertexShader)
gl.AttachShader(program, fragmentShader)
gl.LinkProgram(program)
// Flag shaders for deletion when program is unlinked.
gl.DeleteShader(vertexShader)
gl.DeleteShader(fragmentShader)
if gl.GetProgrami(program, gl.LINK_STATUS) == 0 {
defer gl.DeleteProgram(program)
return gl.Program{}, fmt.Errorf("glutil: %s", gl.GetProgramInfoLog(program))
}
return program, nil
}
func loadShader(shaderType gl.Enum, src string) (gl.Shader, error) {
shader := gl.CreateShader(shaderType)
if shader.Value == 0 {
return gl.Shader{}, fmt.Errorf("glutil: could not create shader (type %v)", shaderType)
}
gl.ShaderSource(shader, src)
gl.CompileShader(shader)
if gl.GetShaderi(shader, gl.COMPILE_STATUS) == 0 {
defer gl.DeleteShader(shader)
return gl.Shader{}, fmt.Errorf("shader compile: %s", gl.GetShaderInfoLog(shader))
}
return shader, nil
}