| // Copyright 2014 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package glutil implements OpenGL utility functions. |
| package glutil // import "golang.org/x/mobile/gl/glutil" |
| |
| import ( |
| "fmt" |
| |
| "golang.org/x/mobile/gl" |
| ) |
| |
| // 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 |
| } |