mirror of
https://git.sr.ht/~eliasnaur/gio
synced 2026-07-01 15:45:38 +00:00
Elias Naur
115 lines
2.8 KiB
Go
115 lines
2.8 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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package gl
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import (
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"errors"
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"fmt"
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"reflect"
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"strings"
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"unsafe"
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)
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func CreateProgram(ctx *Functions, vsSrc, fsSrc string, attribs []string) (Program, error) {
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vs, err := createShader(ctx, VERTEX_SHADER, vsSrc)
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if err != nil {
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return Program{}, err
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}
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defer ctx.DeleteShader(vs)
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fs, err := createShader(ctx, FRAGMENT_SHADER, fsSrc)
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if err != nil {
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return Program{}, err
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}
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defer ctx.DeleteShader(fs)
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prog := ctx.CreateProgram()
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if prog == (Program{}) {
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return Program{}, errors.New("glCreateProgram failed")
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}
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ctx.AttachShader(prog, vs)
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ctx.AttachShader(prog, fs)
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for i, a := range attribs {
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ctx.BindAttribLocation(prog, Attrib(i), a)
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}
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ctx.LinkProgram(prog)
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if ctx.GetProgrami(prog, LINK_STATUS) == 0 {
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log := ctx.GetProgramInfoLog(prog)
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ctx.DeleteProgram(prog)
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return Program{}, fmt.Errorf("program link failed: %s", strings.TrimSpace(log))
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}
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return prog, nil
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}
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func GetUniformLocation(ctx *Functions, prog Program, name string) Uniform {
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loc := ctx.GetUniformLocation(prog, name)
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if !loc.Valid() {
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panic(fmt.Errorf("uniform %s not found", name))
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}
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return loc
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}
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func createShader(ctx *Functions, typ Enum, src string) (Shader, error) {
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sh := ctx.CreateShader(typ)
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if sh == (Shader{}) {
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return Shader{}, errors.New("glCreateShader failed")
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}
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ctx.ShaderSource(sh, src)
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ctx.CompileShader(sh)
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if ctx.GetShaderi(sh, COMPILE_STATUS) == 0 {
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log := ctx.GetShaderInfoLog(sh)
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ctx.DeleteShader(sh)
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return Shader{}, fmt.Errorf("shader compilation failed: %s", strings.TrimSpace(log))
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}
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return sh, nil
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}
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// BytesView returns a byte slice view of a slice.
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func BytesView(s interface{}) []byte {
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v := reflect.ValueOf(s)
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first := v.Index(0)
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sz := int(first.Type().Size())
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return *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
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Data: uintptr(unsafe.Pointer((*reflect.SliceHeader)(unsafe.Pointer(first.UnsafeAddr())))),
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Len: v.Len() * sz,
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Cap: v.Cap() * sz,
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}))
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}
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func ParseGLVersion(glVer string) ([2]int, error) {
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var ver [2]int
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if _, err := fmt.Sscanf(glVer, "OpenGL ES %d.%d", &ver[0], &ver[1]); err == nil {
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return ver, nil
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} else if _, err := fmt.Sscanf(glVer, "WebGL %d.%d", &ver[0], &ver[1]); err == nil {
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// WebGL major version v corresponds to OpenGL ES version v + 1
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ver[0]++
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return ver, nil
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} else if _, err := fmt.Sscanf(glVer, "%d.%d", &ver[0], &ver[1]); err == nil {
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return ver, nil
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}
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return ver, fmt.Errorf("failed to parse OpenGL ES version (%s)", glVer)
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}
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func SliceOf(s uintptr) []byte {
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if s == 0 {
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return nil
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}
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sh := reflect.SliceHeader{
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Data: s,
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Len: 1 << 30,
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Cap: 1 << 30,
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}
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return *(*[]byte)(unsafe.Pointer(&sh))
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}
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// GoString convert a NUL-terminated C string
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// to a Go string.
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func GoString(s []byte) string {
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i := 0
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for {
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if s[i] == 0 {
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break
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}
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i++
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}
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return string(s[:i])
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}
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