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opengl.go
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/
opengl.go
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package opengl
import (
_ "embed"
"fmt"
"strings"
"github.com/go-gl/gl/v3.2-core/gl"
)
func NewShader(vert string, frag string) *State {
vertexShader, err := compileShader(vert, gl.VERTEX_SHADER)
if err != nil {
panic(err)
}
fragmentShader, err := compileShader(frag, gl.FRAGMENT_SHADER)
if err != nil {
panic(err)
}
prog := gl.CreateProgram()
gl.AttachShader(prog, vertexShader)
gl.AttachShader(prog, fragmentShader)
gl.LinkProgram(prog)
gl.Enable(gl.BLEND)
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
gl.LineWidth(2.0)
gl.PointSize(2.0)
gl.Enable(gl.DEPTH_TEST)
gl.DepthFunc(gl.LEQUAL)
gl.ClearColor(0.3, 0.3, 0.5, 1.0)
return &State{
program: &Program{id: prog}, bufferCount: 0,
}
}
func compileShader(source string, shaderType uint32) (uint32, error) {
shader := gl.CreateShader(shaderType)
csources, free := gl.Strs(source + "\x00")
defer free()
gl.ShaderSource(shader, 1, csources, nil)
gl.CompileShader(shader)
var status int32
gl.GetShaderiv(shader, gl.COMPILE_STATUS, &status)
if status == gl.FALSE {
var logLength int32
gl.GetShaderiv(shader, gl.INFO_LOG_LENGTH, &logLength)
log := strings.Repeat("\x00", int(logLength+1))
gl.GetShaderInfoLog(shader, logLength, nil, gl.Str(log))
return 0, fmt.Errorf("failed to compile %v: %v", source, log)
}
return shader, nil
}