mirror of
https://git.sr.ht/~eliasnaur/gio
synced 2026-07-01 15:45:38 +00:00
Elias Naur
3ae5a37c24
A recent change made the OpenGL functions an interface of the functions required for the implementation of GPU, a renderer for Gio operations. That allowed for running Gio on external systems where OpenGL is available. However, to allow for non-OpenGL flavored backends such as Vulkan, Metal and Direct3D, this change introduces Backend for the high-level operations required by GPU. This change also adds a concrete backend to package gl. Type Backend is a first cut heavily based on OpenGL. Future changes will add more backends, where the Backend interface quite possibly will need refinement. Signed-off-by: Elias Naur <mail@eliasnaur.com>
76 lines
2.0 KiB
Go
76 lines
2.0 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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"strings"
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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.Valid() {
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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.Valid() {
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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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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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