func (prg *Program) CreateAndLink(ctx gl.Context, compilers ...func(gl.Context) gl.Shader) {
prg.Program = ctx.CreateProgram()
for _, c := range compilers {
s := c(ctx)
ctx.AttachShader(prg.Program, s)
defer ctx.DeleteShader(s)
}
ctx.LinkProgram(prg.Program)
if ctx.GetProgrami(prg.Program, gl.LINK_STATUS) == 0 {
log.Fatalf("program link: %s", ctx.GetProgramInfoLog(prg.Program))
}
}
func loadShader(glctx gl.Context, shaderType gl.Enum, src string) (gl.Shader, error) {
shader := glctx.CreateShader(shaderType)
if shader.Value == 0 {
return gl.Shader{}, fmt.Errorf("glutil: could not create shader (type %v)", shaderType)
}
glctx.ShaderSource(shader, src)
glctx.CompileShader(shader)
if glctx.GetShaderi(shader, gl.COMPILE_STATUS) == 0 {
defer glctx.DeleteShader(shader)
return gl.Shader{}, fmt.Errorf("shader compile: %s", glctx.GetShaderInfoLog(shader))
}
return shader, nil
}
func loadShader(glctx gl.Context, shaderType gl.Enum, assetName string) (gl.Shader, error) {
// Borrowed from golang.org/x/mobile/exp/gl/glutil
src, err := loadAsset(assetName)
if err != nil {
return gl.Shader{}, err
}
shader := glctx.CreateShader(shaderType)
if shader.Value == 0 {
return gl.Shader{}, fmt.Errorf("glutil: could not create shader (type %v)", shaderType)
}
glctx.ShaderSource(shader, string(src))
glctx.CompileShader(shader)
if glctx.GetShaderi(shader, gl.COMPILE_STATUS) == 0 {
defer glctx.DeleteShader(shader)
return gl.Shader{}, fmt.Errorf("shader compile: %s", glctx.GetShaderInfoLog(shader))
}
return shader, nil
}
func LoadShaders(glctx gl.Context, program gl.Program, vertexAsset, fragmentAsset string) error {
vertexShader, err := loadShader(glctx, gl.VERTEX_SHADER, vertexAsset)
if err != nil {
return err
}
fragmentShader, err := loadShader(glctx, gl.FRAGMENT_SHADER, fragmentAsset)
if err != nil {
glctx.DeleteShader(vertexShader)
return err
}
if glctx.GetProgrami(program, gl.ATTACHED_SHADERS) > 0 {
for _, shader := range glctx.GetAttachedShaders(program) {
glctx.DetachShader(program, shader)
}
}
glctx.AttachShader(program, vertexShader)
glctx.AttachShader(program, fragmentShader)
glctx.LinkProgram(program)
// Flag shaders for deletion when program is unlinked.
glctx.DeleteShader(vertexShader)
glctx.DeleteShader(fragmentShader)
if glctx.GetProgrami(program, gl.LINK_STATUS) == 0 {
defer glctx.DeleteProgram(program)
return fmt.Errorf("LoadShaders: %s", glctx.GetProgramInfoLog(program))
}
return nil
}
// CreateProgram creates, compiles, and links a gl.Program.
func CreateProgram(glctx gl.Context, vertexSrc, fragmentSrc string) (gl.Program, error) {
program := glctx.CreateProgram()
if program.Value == 0 {
return gl.Program{}, fmt.Errorf("glutil: no programs available")
}
vertexShader, err := loadShader(glctx, gl.VERTEX_SHADER, vertexSrc)
if err != nil {
return gl.Program{}, err
}
fragmentShader, err := loadShader(glctx, gl.FRAGMENT_SHADER, fragmentSrc)
if err != nil {
glctx.DeleteShader(vertexShader)
return gl.Program{}, err
}
glctx.AttachShader(program, vertexShader)
glctx.AttachShader(program, fragmentShader)
glctx.LinkProgram(program)
// Flag shaders for deletion when program is unlinked.
glctx.DeleteShader(vertexShader)
glctx.DeleteShader(fragmentShader)
if glctx.GetProgrami(program, gl.LINK_STATUS) == 0 {
defer glctx.DeleteProgram(program)
return gl.Program{}, fmt.Errorf("glutil: %s", glctx.GetProgramInfoLog(program))
}
return program, nil
}