/
glutil.go
58 lines (49 loc) · 1.68 KB
/
glutil.go
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// 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 "github.com/goxjs/gl/glutil"
import (
"fmt"
"github.com/goxjs/gl"
)
// 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 loadShader(shaderType gl.Enum, src string) (gl.Shader, error) {
shader := gl.CreateShader(shaderType)
if !shader.Valid() {
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
}