internal/gl: rename internal/glimpl

Now that the OpenGL driver package is named "opengl", we can finally get
rid of the ugly "glimpl" name.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

internal/gl/util.go

@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package gl
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+func CreateProgram(ctx *Functions, vsSrc, fsSrc string, attribs []string) (Program, error) {
+	vs, err := createShader(ctx, VERTEX_SHADER, vsSrc)
+	if err != nil {
+		return Program{}, err
+	}
+	defer ctx.DeleteShader(vs)
+	fs, err := createShader(ctx, FRAGMENT_SHADER, fsSrc)
+	if err != nil {
+		return Program{}, err
+	}
+	defer ctx.DeleteShader(fs)
+	prog := ctx.CreateProgram()
+	if !prog.Valid() {
+		return Program{}, errors.New("glCreateProgram failed")
+	}
+	ctx.AttachShader(prog, vs)
+	ctx.AttachShader(prog, fs)
+	for i, a := range attribs {
+		ctx.BindAttribLocation(prog, Attrib(i), a)
+	}
+	ctx.LinkProgram(prog)
+	if ctx.GetProgrami(prog, LINK_STATUS) == 0 {
+		log := ctx.GetProgramInfoLog(prog)
+		ctx.DeleteProgram(prog)
+		return Program{}, fmt.Errorf("program link failed: %s", strings.TrimSpace(log))
+	}
+	return prog, nil
+}
+
+func CreateComputeProgram(ctx *Functions, src string) (Program, error) {
+	cs, err := createShader(ctx, COMPUTE_SHADER, src)
+	if err != nil {
+		return Program{}, err
+	}
+	defer ctx.DeleteShader(cs)
+	prog := ctx.CreateProgram()
+	if !prog.Valid() {
+		return Program{}, errors.New("glCreateProgram failed")
+	}
+	ctx.AttachShader(prog, cs)
+	ctx.LinkProgram(prog)
+	if ctx.GetProgrami(prog, LINK_STATUS) == 0 {
+		log := ctx.GetProgramInfoLog(prog)
+		ctx.DeleteProgram(prog)
+		return Program{}, fmt.Errorf("program link failed: %s", strings.TrimSpace(log))
+	}
+	return prog, nil
+}
+
+func createShader(ctx *Functions, typ Enum, src string) (Shader, error) {
+	sh := ctx.CreateShader(typ)
+	if !sh.Valid() {
+		return Shader{}, errors.New("glCreateShader failed")
+	}
+	ctx.ShaderSource(sh, src)
+	ctx.CompileShader(sh)
+	if ctx.GetShaderi(sh, COMPILE_STATUS) == 0 {
+		log := ctx.GetShaderInfoLog(sh)
+		ctx.DeleteShader(sh)
+		return Shader{}, fmt.Errorf("shader compilation failed: %s", strings.TrimSpace(log))
+	}
+	return sh, nil
+}
+
+func ParseGLVersion(glVer string) (version [2]int, gles bool, err error) {
+	var ver [2]int
+	if _, err := fmt.Sscanf(glVer, "OpenGL ES %d.%d", &ver[0], &ver[1]); err == nil {
+		return ver, true, nil
+	} else if _, err := fmt.Sscanf(glVer, "WebGL %d.%d", &ver[0], &ver[1]); err == nil {
+		// WebGL major version v corresponds to OpenGL ES version v + 1
+		ver[0]++
+		return ver, true, nil
+	} else if _, err := fmt.Sscanf(glVer, "%d.%d", &ver[0], &ver[1]); err == nil {
+		return ver, false, nil
+	}
+	return ver, false, fmt.Errorf("failed to parse OpenGL ES version (%s)", glVer)
+}