84 lines
2.1 KiB
Go
84 lines
2.1 KiB
Go
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package main
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import (
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"fmt"
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"github.com/go-gl/gl/v4.1-core/gl"
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"github.com/go-gl/mathgl/mgl32"
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)
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type Shader struct {
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ProgramID uint32
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}
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func NewShader(vSource, fSource string) (*Shader, error) {
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vertexShader := compileShader(gl.VERTEX_SHADER, vSource)
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fragmentShader := compileShader(gl.FRAGMENT_SHADER, fSource)
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program := gl.CreateProgram()
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gl.AttachShader(program, vertexShader)
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gl.AttachShader(program, fragmentShader)
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gl.LinkProgram(program)
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var success int32
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gl.GetProgramiv(program, gl.LINK_STATUS, &success)
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if success == gl.FALSE {
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var logLength int32
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gl.GetProgramiv(program, gl.INFO_LOG_LENGTH, &logLength)
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log := make([]byte, logLength+1)
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gl.GetProgramInfoLog(program, logLength, nil, &log[0])
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fmt.Printf("Failed to link program: %s\n", log)
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return nil, fmt.Errorf("failed to link shader program")
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}
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gl.DeleteShader(vertexShader)
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gl.DeleteShader(fragmentShader)
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return &Shader{ProgramID: program}, nil
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}
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func (s *Shader) Use() {
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gl.UseProgram(s.ProgramID)
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}
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func (s *Shader) SetUniform(name string, value float32) {
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location := s.getUniformLocation(name)
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gl.Uniform1f(location, value)
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}
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func (s *Shader) SetUniformM(name string, matrix mgl32.Mat4) {
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location := s.getUniformLocation(name)
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gl.UniformMatrix4fv(location, 1, false, &matrix[0])
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}
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func (s *Shader) SetUniform4f(name string, v0, v1, v2, v3 float32) {
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location := gl.GetUniformLocation(s.ProgramID, gl.Str(name+"\x00"))
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gl.Uniform4f(location, v0, v1, v2, v3)
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}
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func (s *Shader) getUniformLocation(name string) int32 {
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cName := gl.Str(name + "\x00")
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return gl.GetUniformLocation(s.ProgramID, cName)
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}
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func compileShader(shaderType uint32, source string) uint32 {
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shader := gl.CreateShader(shaderType)
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cSource, free := gl.Strs(source + "\x00")
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gl.ShaderSource(shader, 1, cSource, nil)
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free()
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gl.CompileShader(shader)
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var success int32
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gl.GetShaderiv(shader, gl.COMPILE_STATUS, &success)
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if success == gl.FALSE {
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var logLength int32
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gl.GetShaderiv(shader, gl.INFO_LOG_LENGTH, &logLength)
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log := make([]byte, logLength+1)
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gl.GetShaderInfoLog(shader, logLength, nil, &log[0])
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fmt.Printf("Failed to compile shader: %s\n", log)
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}
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return shader
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}
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