github.com/utopiagio/gio@v0.0.8/internal/gl/util.go (about)

     1  // SPDX-License-Identifier: Unlicense OR MIT
     2  
     3  package gl
     4  
     5  import (
     6  	"errors"
     7  	"fmt"
     8  	"strings"
     9  )
    10  
    11  func CreateProgram(ctx *Functions, vsSrc, fsSrc string, attribs []string) (Program, error) {
    12  	vs, err := CreateShader(ctx, VERTEX_SHADER, vsSrc)
    13  	if err != nil {
    14  		return Program{}, err
    15  	}
    16  	defer ctx.DeleteShader(vs)
    17  	fs, err := CreateShader(ctx, FRAGMENT_SHADER, fsSrc)
    18  	if err != nil {
    19  		return Program{}, err
    20  	}
    21  	defer ctx.DeleteShader(fs)
    22  	prog := ctx.CreateProgram()
    23  	if !prog.Valid() {
    24  		return Program{}, errors.New("glCreateProgram failed")
    25  	}
    26  	ctx.AttachShader(prog, vs)
    27  	ctx.AttachShader(prog, fs)
    28  	for i, a := range attribs {
    29  		ctx.BindAttribLocation(prog, Attrib(i), a)
    30  	}
    31  	ctx.LinkProgram(prog)
    32  	if ctx.GetProgrami(prog, LINK_STATUS) == 0 {
    33  		log := ctx.GetProgramInfoLog(prog)
    34  		ctx.DeleteProgram(prog)
    35  		return Program{}, fmt.Errorf("program link failed: %s", strings.TrimSpace(log))
    36  	}
    37  	return prog, nil
    38  }
    39  
    40  func CreateComputeProgram(ctx *Functions, src string) (Program, error) {
    41  	cs, err := CreateShader(ctx, COMPUTE_SHADER, src)
    42  	if err != nil {
    43  		return Program{}, err
    44  	}
    45  	defer ctx.DeleteShader(cs)
    46  	prog := ctx.CreateProgram()
    47  	if !prog.Valid() {
    48  		return Program{}, errors.New("glCreateProgram failed")
    49  	}
    50  	ctx.AttachShader(prog, cs)
    51  	ctx.LinkProgram(prog)
    52  	if ctx.GetProgrami(prog, LINK_STATUS) == 0 {
    53  		log := ctx.GetProgramInfoLog(prog)
    54  		ctx.DeleteProgram(prog)
    55  		return Program{}, fmt.Errorf("program link failed: %s", strings.TrimSpace(log))
    56  	}
    57  	return prog, nil
    58  }
    59  
    60  func CreateShader(ctx *Functions, typ Enum, src string) (Shader, error) {
    61  	sh := ctx.CreateShader(typ)
    62  	if !sh.Valid() {
    63  		return Shader{}, errors.New("glCreateShader failed")
    64  	}
    65  	ctx.ShaderSource(sh, src)
    66  	ctx.CompileShader(sh)
    67  	if ctx.GetShaderi(sh, COMPILE_STATUS) == 0 {
    68  		log := ctx.GetShaderInfoLog(sh)
    69  		ctx.DeleteShader(sh)
    70  		return Shader{}, fmt.Errorf("shader compilation failed: %s", strings.TrimSpace(log))
    71  	}
    72  	return sh, nil
    73  }
    74  
    75  func ParseGLVersion(glVer string) (version [2]int, gles bool, err error) {
    76  	var ver [2]int
    77  	if _, err := fmt.Sscanf(glVer, "OpenGL ES %d.%d", &ver[0], &ver[1]); err == nil {
    78  		return ver, true, nil
    79  	} else if _, err := fmt.Sscanf(glVer, "WebGL %d.%d", &ver[0], &ver[1]); err == nil {
    80  		// WebGL major version v corresponds to OpenGL ES version v + 1
    81  		ver[0]++
    82  		return ver, true, nil
    83  	} else if _, err := fmt.Sscanf(glVer, "%d.%d", &ver[0], &ver[1]); err == nil {
    84  		return ver, false, nil
    85  	}
    86  	return ver, false, fmt.Errorf("failed to parse OpenGL ES version (%s)", glVer)
    87  }