func newShaderProgram(ctx *context, vsSource, fsSource string) *shaderProgram {
vs := compile(vsSource, gl.VERTEX_SHADER)
fs := compile(fsSource, gl.FRAGMENT_SHADER)
program := gl.CreateProgram()
gl.AttachShader(program, vs)
gl.AttachShader(program, fs)
gl.LinkProgram(program)
if gl.GetProgrami(program, gl.LINK_STATUS) != gl.TRUE {
panic(gl.GetProgramInfoLog(program))
}
gl.UseProgram(program)
checkError()
uniformCount := gl.GetProgrami(program, gl.ACTIVE_UNIFORMS)
uniforms := make([]shaderUniform, uniformCount)
textureUnit := 0
for i := range uniforms {
name, size, ty := gl.GetActiveUniform(program, uint32(i))
location := gl.GetUniformLocation(program, name)
uniforms[i] = shaderUniform{
name: name,
size: size,
ty: shaderDataType(ty),
location: location,
textureUnit: textureUnit,
}
if ty == gl.SAMPLER_2D {
textureUnit++
}
}
attributeCount := gl.GetProgrami(program, gl.ACTIVE_ATTRIBUTES)
attributes := make([]shaderAttribute, attributeCount)
for i := range attributes {
name, size, ty := gl.GetActiveAttrib(program, uint32(i))
location := gl.GetAttribLocation(program, name)
attributes[i] = shaderAttribute{
name: name,
size: size,
ty: shaderDataType(ty),
location: location,
}
}
ctx.stats.shaderProgramCount++
return &shaderProgram{
program: program,
uniforms: uniforms,
attributes: attributes,
}
}
// CreateProgram creates, compiles, and links a gl.Program.
func CreateProgram(vertexSrc, fragmentSrc string) (gl.Program, error) {
program := gl.CreateProgram()
if !program.Valid() {
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 (s *glShader) createShader(name, header, opts, vShader, fShader string) error {
program := gl.CreateProgram()
vertexShader := gl.CreateShader(gl.VERTEX_SHADER)
gl.ShaderSource(vertexShader, strings.Join([]string{header, opts, vShader}, "\n"))
gl.CompileShader(vertexShader)
status := gl.Enum(gl.GetShaderi(vertexShader, gl.COMPILE_STATUS))
if status != gl.TRUE {
return dumpShaderError(vertexShader, name, "vert")
}
fragmentShader := gl.CreateShader(gl.FRAGMENT_SHADER)
gl.ShaderSource(fragmentShader, strings.Join([]string{header, opts, fShader}, "\n"))
gl.CompileShader(fragmentShader)
status = gl.Enum(gl.GetShaderi(fragmentShader, gl.COMPILE_STATUS))
if status != gl.TRUE {
return dumpShaderError(fragmentShader, name, "vert")
}
gl.AttachShader(program, vertexShader)
gl.AttachShader(program, fragmentShader)
gl.LinkProgram(program)
status = gl.Enum(gl.GetProgrami(program, gl.LINK_STATUS))
if status != gl.TRUE {
return dumpProgramError(program, name)
}
s.vertexAttrib = gl.GetAttribLocation(program, "vertex")
s.tcoordAttrib = gl.GetAttribLocation(program, "tcoord")
s.program = program
s.vertex = vertexShader
s.fragment = fragmentShader
return nil
}