/
gldriver.go
133 lines (118 loc) · 3.68 KB
/
gldriver.go
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// Copyright 2015 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 gldriver provides an OpenGL driver for accessing a screen.
package gldriver
import (
"encoding/binary"
"fmt"
"math"
"golang.org/x/exp/shiny/driver/internal/errscreen"
"golang.org/x/exp/shiny/screen"
"golang.org/x/image/math/f64"
"golang.org/x/mobile/gl"
)
// Main is called by the program's main function to run the graphical
// application.
//
// It calls f on the Screen, possibly in a separate goroutine, as some OS-
// specific libraries require being on 'the main thread'. It returns when f
// returns.
func Main(f func(screen.Screen)) {
if err := main(f); err != nil {
f(errscreen.Stub(err))
}
}
func mul(a, b f64.Aff3) f64.Aff3 {
return f64.Aff3{
a[0]*b[0] + a[1]*b[3],
a[0]*b[1] + a[1]*b[4],
a[0]*b[2] + a[1]*b[5] + a[2],
a[3]*b[0] + a[4]*b[3],
a[3]*b[1] + a[4]*b[4],
a[3]*b[2] + a[4]*b[5] + a[5],
}
}
// writeAff3 must only be called while holding windowImpl.glctxMu.
func writeAff3(glctx gl.Context, u gl.Uniform, a f64.Aff3) {
var m [9]float32
m[0*3+0] = float32(a[0*3+0])
m[0*3+1] = float32(a[1*3+0])
m[0*3+2] = 0
m[1*3+0] = float32(a[0*3+1])
m[1*3+1] = float32(a[1*3+1])
m[1*3+2] = 0
m[2*3+0] = float32(a[0*3+2])
m[2*3+1] = float32(a[1*3+2])
m[2*3+2] = 1
glctx.UniformMatrix3fv(u, m[:])
}
// f32Bytes returns the byte representation of float32 values in the given byte
// order. byteOrder must be either binary.BigEndian or binary.LittleEndian.
func f32Bytes(byteOrder binary.ByteOrder, values ...float32) []byte {
le := false
switch byteOrder {
case binary.BigEndian:
case binary.LittleEndian:
le = true
default:
panic(fmt.Sprintf("invalid byte order %v", byteOrder))
}
b := make([]byte, 4*len(values))
for i, v := range values {
u := math.Float32bits(v)
if le {
b[4*i+0] = byte(u >> 0)
b[4*i+1] = byte(u >> 8)
b[4*i+2] = byte(u >> 16)
b[4*i+3] = byte(u >> 24)
} else {
b[4*i+0] = byte(u >> 24)
b[4*i+1] = byte(u >> 16)
b[4*i+2] = byte(u >> 8)
b[4*i+3] = byte(u >> 0)
}
}
return b
}
// compileProgram must only be called while holding windowImpl.glctxMu.
func compileProgram(glctx gl.Context, vSrc, fSrc string) (gl.Program, error) {
program := glctx.CreateProgram()
if program.Value == 0 {
return gl.Program{}, fmt.Errorf("gldriver: no programs available")
}
vertexShader, err := compileShader(glctx, gl.VERTEX_SHADER, vSrc)
if err != nil {
return gl.Program{}, err
}
fragmentShader, err := compileShader(glctx, gl.FRAGMENT_SHADER, fSrc)
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("gldriver: program compile: %s", glctx.GetProgramInfoLog(program))
}
return program, nil
}
// compileShader must only be called while holding windowImpl.glctxMu.
func compileShader(glctx gl.Context, shaderType gl.Enum, src string) (gl.Shader, error) {
shader := glctx.CreateShader(shaderType)
if shader.Value == 0 {
return gl.Shader{}, fmt.Errorf("gldriver: 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("gldriver: shader compile: %s", glctx.GetShaderInfoLog(shader))
}
return shader, nil
}