467d8559f2
In the long term, a lot of this package should be removed in favor of the golang.org/x/image/math/f32 package. The latter is the common location for matrix types shared across graphics libraries. For example, the golang.org/x/image/draw package refers to golang.org/x/image/math/f64. Change-Id: I9d7ccd3cb35912e0d9dc5bd46c919516ea840340 Reviewed-on: https://go-review.googlesource.com/11856 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
75 lines
2.1 KiB
Go
75 lines
2.1 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package glutil implements OpenGL utility functions.
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package glutil // import "golang.org/x/mobile/exp/gl/glutil"
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import (
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"fmt"
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"golang.org/x/mobile/exp/f32"
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"golang.org/x/mobile/gl"
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)
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// CreateProgram creates, compiles, and links a gl.Program.
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func CreateProgram(vertexSrc, fragmentSrc string) (gl.Program, error) {
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program := gl.CreateProgram()
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if program.Value == 0 {
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return gl.Program{}, fmt.Errorf("glutil: no programs available")
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}
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vertexShader, err := loadShader(gl.VERTEX_SHADER, vertexSrc)
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if err != nil {
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return gl.Program{}, err
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}
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fragmentShader, err := loadShader(gl.FRAGMENT_SHADER, fragmentSrc)
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if err != nil {
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gl.DeleteShader(vertexShader)
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return gl.Program{}, err
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}
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gl.AttachShader(program, vertexShader)
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gl.AttachShader(program, fragmentShader)
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gl.LinkProgram(program)
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// Flag shaders for deletion when program is unlinked.
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gl.DeleteShader(vertexShader)
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gl.DeleteShader(fragmentShader)
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if gl.GetProgrami(program, gl.LINK_STATUS) == 0 {
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defer gl.DeleteProgram(program)
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return gl.Program{}, fmt.Errorf("glutil: %s", gl.GetProgramInfoLog(program))
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}
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return program, nil
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}
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func loadShader(shaderType gl.Enum, src string) (gl.Shader, error) {
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shader := gl.CreateShader(shaderType)
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if shader.Value == 0 {
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return gl.Shader{}, fmt.Errorf("glutil: could not create shader (type %v)", shaderType)
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}
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gl.ShaderSource(shader, src)
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gl.CompileShader(shader)
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if gl.GetShaderi(shader, gl.COMPILE_STATUS) == 0 {
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defer gl.DeleteShader(shader)
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return gl.Shader{}, fmt.Errorf("shader compile: %s", gl.GetShaderInfoLog(shader))
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}
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return shader, nil
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}
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// writeAffine writes the contents of an Affine to a 3x3 matrix GL uniform.
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func writeAffine(u gl.Uniform, a *f32.Affine) {
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var m [9]float32
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m[0*3+0] = a[0][0]
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m[0*3+1] = a[1][0]
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m[0*3+2] = 0
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m[1*3+0] = a[0][1]
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m[1*3+1] = a[1][1]
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m[1*3+2] = 0
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m[2*3+0] = a[0][2]
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m[2*3+1] = a[1][2]
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m[2*3+2] = 1
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gl.UniformMatrix3fv(u, m[:])
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}
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