go-opengl-pixel/pixelgl/shader.go

236 lines
6.2 KiB
Go

package pixelgl
import (
"fmt"
"runtime"
"github.com/go-gl/gl/v3.3-core/gl"
"github.com/go-gl/mathgl/mgl32"
)
// Shader is an OpenGL shader program.
type Shader struct {
parent Doer
program binder
vertexFmt AttrFormat
uniformFmt AttrFormat
uniforms map[string]int32
}
// NewShader creates a new shader program from the specified vertex shader and fragment shader sources.
//
// Note that vertexShader and fragmentShader parameters must contain the source code, they're not filenames.
func NewShader(parent Doer, vertexFmt, uniformFmt AttrFormat, vertexShader, fragmentShader string) (*Shader, error) {
shader := &Shader{
parent: parent,
program: binder{
restoreLoc: gl.CURRENT_PROGRAM,
bindFunc: func(obj uint32) {
gl.UseProgram(obj)
},
},
vertexFmt: vertexFmt,
uniformFmt: uniformFmt,
uniforms: make(map[string]int32),
}
var err error
parent.Do(func(ctx Context) {
err = DoErr(func() error {
var vshader, fshader uint32
// vertex shader
{
vshader = gl.CreateShader(gl.VERTEX_SHADER)
src, free := gl.Strs(vertexShader)
defer free()
length := int32(len(vertexShader))
gl.ShaderSource(vshader, 1, src, &length)
gl.CompileShader(vshader)
var (
success int32
infoLog = make([]byte, 512)
)
gl.GetShaderiv(vshader, gl.COMPILE_STATUS, &success)
if success == 0 {
gl.GetShaderInfoLog(vshader, int32(len(infoLog)), nil, &infoLog[0])
return fmt.Errorf("error compiling vertex shader: %s", string(infoLog))
}
defer gl.DeleteShader(vshader)
}
// fragment shader
{
fshader = gl.CreateShader(gl.FRAGMENT_SHADER)
src, free := gl.Strs(fragmentShader)
defer free()
length := int32(len(fragmentShader))
gl.ShaderSource(fshader, 1, src, &length)
gl.CompileShader(fshader)
var (
success int32
infoLog = make([]byte, 512)
)
gl.GetShaderiv(fshader, gl.COMPILE_STATUS, &success)
if success == 0 {
gl.GetShaderInfoLog(fshader, int32(len(infoLog)), nil, &infoLog[0])
return fmt.Errorf("error compiling fragment shader: %s", string(infoLog))
}
defer gl.DeleteShader(fshader)
}
// shader program
{
shader.program.obj = gl.CreateProgram()
gl.AttachShader(shader.program.obj, vshader)
gl.AttachShader(shader.program.obj, fshader)
gl.LinkProgram(shader.program.obj)
var (
success int32
infoLog = make([]byte, 512)
)
gl.GetProgramiv(shader.program.obj, gl.LINK_STATUS, &success)
if success == 0 {
gl.GetProgramInfoLog(shader.program.obj, int32(len(infoLog)), nil, &infoLog[0])
return fmt.Errorf("error linking shader program: %s", string(infoLog))
}
}
// uniforms
for name := range uniformFmt {
loc := gl.GetUniformLocation(shader.program.obj, gl.Str(name+"\x00"))
shader.uniforms[name] = loc
}
return nil
})
})
if err != nil {
return nil, err
}
runtime.SetFinalizer(shader, (*Shader).delete)
return shader, nil
}
func (s *Shader) delete() {
DoNoBlock(func() {
gl.DeleteProgram(s.program.obj)
})
}
// ID returns an OpenGL identifier of a shader program.
func (s *Shader) ID() uint32 {
return s.program.obj
}
// VertexFormat returns the vertex attribute format of this shader. Do not change it.
func (s *Shader) VertexFormat() AttrFormat {
return s.vertexFmt
}
// UniformFormat returns the uniform attribute format of this shader. Do not change it.
func (s *Shader) UniformFormat() AttrFormat {
return s.uniformFmt
}
// SetUniformAttr sets the value of a uniform attribute of a shader.
//
// If the attribute does not exist, this method returns false.
//
// Supplied value must correspond to the type of the attribute. Correct types are these (right-hand is the type of the value):
// Attr{Type: Int}: int32
// Attr{Type: Float}: float32
// Attr{Type: Vec2}: mgl32.Vec2
// Attr{Type: Vec3}: mgl32.Vec3
// Attr{Type: Vec4}: mgl32.Vec4
// Attr{Type: Mat2}: mgl32.Mat2
// Attr{Type: Mat23}: mgl32.Mat2x3
// Attr{Type: Mat24}: mgl32.Mat2x4
// Attr{Type: Mat3}: mgl32.Mat3
// Attr{Type: Mat32}: mgl32.Mat3x2
// Attr{Type: Mat34}: mgl32.Mat3x4
// Attr{Type: Mat4}: mgl32.Mat4
// Attr{Type: Mat42}: mgl32.Mat4x2
// Attr{Type: Mat43}: mgl32.Mat4x3
// No other types are supported.
func (s *Shader) SetUniformAttr(attr Attr, value interface{}) (ok bool) {
if !s.uniformFmt.Contains(attr) {
return false
}
DoNoBlock(func() {
s.program.bind()
switch attr.Type {
case Int:
value := value.(int32)
gl.Uniform1iv(s.uniforms[attr.Name], 1, &value)
case Float:
value := value.(float32)
gl.Uniform1fv(s.uniforms[attr.Name], 1, &value)
case Vec2:
value := value.(mgl32.Vec2)
gl.Uniform2fv(s.uniforms[attr.Name], 1, &value[0])
case Vec3:
value := value.(mgl32.Vec3)
gl.Uniform3fv(s.uniforms[attr.Name], 1, &value[0])
case Vec4:
value := value.(mgl32.Vec4)
gl.Uniform4fv(s.uniforms[attr.Name], 1, &value[0])
case Mat2:
value := value.(mgl32.Mat2)
gl.UniformMatrix2fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat23:
value := value.(mgl32.Mat2x3)
gl.UniformMatrix2x3fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat24:
value := value.(mgl32.Mat2x4)
gl.UniformMatrix2x4fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat3:
value := value.(mgl32.Mat3)
gl.UniformMatrix3fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat32:
value := value.(mgl32.Mat3x2)
gl.UniformMatrix3x2fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat34:
value := value.(mgl32.Mat3x4)
gl.UniformMatrix3x4fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat4:
value := value.(mgl32.Mat4)
gl.UniformMatrix4fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat42:
value := value.(mgl32.Mat4x2)
gl.UniformMatrix4x2fv(s.uniforms[attr.Name], 1, false, &value[0])
case Mat43:
value := value.(mgl32.Mat4x3)
gl.UniformMatrix4x3fv(s.uniforms[attr.Name], 1, false, &value[0])
default:
panic("set uniform attr: invalid attribute type")
}
s.program.restore()
})
return true
}
// Do stars using a shader, executes sub, and stops using it.
func (s *Shader) Do(sub func(Context)) {
s.parent.Do(func(ctx Context) {
DoNoBlock(func() {
s.program.bind()
})
sub(ctx.WithShader(s))
DoNoBlock(func() {
s.program.restore()
})
})
}