ebiten/internal/shaderir/metal/metal.go

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// Copyright 2020 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package metal
import (
"fmt"
"go/constant"
"go/token"
"regexp"
"strings"
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"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
)
const (
vertexOut = "varyings"
fragmentOut = "out"
)
type compileContext struct {
structNames map[string]string
structTypes []shaderir.Type
}
func (c *compileContext) structName(p *shaderir.Program, t *shaderir.Type) string {
if t.Main != shaderir.Struct {
panic("metal: the given type at structName must be a struct")
}
s := t.String()
if n, ok := c.structNames[s]; ok {
return n
}
n := fmt.Sprintf("S%d", len(c.structNames))
c.structNames[s] = n
c.structTypes = append(c.structTypes, *t)
return n
}
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const Prelude = `#include <metal_stdlib>
using namespace metal;
constexpr sampler texture_sampler{filter::nearest};
template<typename T>
T mod(T x, T y) {
return x - y * floor(x/y);
}`
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func Compile(p *shaderir.Program, vertex, fragment string) (shader string) {
c := &compileContext{
structNames: map[string]string{},
}
var lines []string
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lines = append(lines, strings.Split(Prelude, "\n")...)
lines = append(lines, "", "{{.Structs}}")
if len(p.Attributes) > 0 {
lines = append(lines, "")
lines = append(lines, "struct Attributes {")
for i, a := range p.Attributes {
lines = append(lines, fmt.Sprintf("\t%s;", c.metalVarDecl(p, &a, fmt.Sprintf("M%d", i), true, false)))
}
lines = append(lines, "};")
}
if len(p.Varyings) > 0 {
lines = append(lines, "")
lines = append(lines, "struct Varyings {")
lines = append(lines, "\tfloat4 Position [[position]];")
for i, v := range p.Varyings {
lines = append(lines, fmt.Sprintf("\t%s;", c.metalVarDecl(p, &v, fmt.Sprintf("M%d", i), false, false)))
}
lines = append(lines, "};")
}
if len(p.Funcs) > 0 {
lines = append(lines, "")
for _, f := range p.Funcs {
lines = append(lines, c.metalFunc(p, &f, true)...)
}
for _, f := range p.Funcs {
if len(lines) > 0 && lines[len(lines)-1] != "" {
lines = append(lines, "")
}
lines = append(lines, c.metalFunc(p, &f, false)...)
}
}
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if p.VertexFunc.Block != nil && len(p.VertexFunc.Block.Stmts) > 0 {
lines = append(lines, "")
lines = append(lines,
fmt.Sprintf("vertex Varyings %s(", vertex),
"\tuint vid [[vertex_id]],",
"\tconst device Attributes* attributes [[buffer(0)]]")
for i, u := range p.Uniforms {
lines[len(lines)-1] += ","
lines = append(lines, fmt.Sprintf("\tconstant %s [[buffer(%d)]]", c.metalVarDecl(p, &u, fmt.Sprintf("U%d", i), false, true), i+1))
}
for i := 0; i < p.TextureNum; i++ {
lines[len(lines)-1] += ","
lines = append(lines, fmt.Sprintf("\ttexture2d<float> T%[1]d [[texture(%[1]d)]]", i))
}
lines[len(lines)-1] += ") {"
lines = append(lines, fmt.Sprintf("\tVaryings %s = {};", vertexOut))
lines = append(lines, c.metalBlock(p, p.VertexFunc.Block, p.VertexFunc.Block, 0)...)
if last := fmt.Sprintf("\treturn %s;", vertexOut); lines[len(lines)-1] != last {
lines = append(lines, last)
}
lines = append(lines, "}")
}
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if p.FragmentFunc.Block != nil && len(p.FragmentFunc.Block.Stmts) > 0 {
lines = append(lines, "")
lines = append(lines,
fmt.Sprintf("fragment float4 %s(", fragment),
"\tVaryings varyings [[stage_in]]")
for i, u := range p.Uniforms {
lines[len(lines)-1] += ","
lines = append(lines, fmt.Sprintf("\tconstant %s [[buffer(%d)]]", c.metalVarDecl(p, &u, fmt.Sprintf("U%d", i), false, true), i+1))
}
for i := 0; i < p.TextureNum; i++ {
lines[len(lines)-1] += ","
lines = append(lines, fmt.Sprintf("\ttexture2d<float> T%[1]d [[texture(%[1]d)]]", i))
}
lines[len(lines)-1] += ") {"
lines = append(lines, fmt.Sprintf("\tfloat4 %s = float4(0);", fragmentOut))
lines = append(lines, c.metalBlock(p, p.FragmentFunc.Block, p.FragmentFunc.Block, 0)...)
if last := fmt.Sprintf("\treturn %s;", fragmentOut); lines[len(lines)-1] != last {
lines = append(lines, last)
}
lines = append(lines, "}")
}
ls := strings.Join(lines, "\n")
// Struct types are determined after converting the program.
if len(c.structTypes) > 0 {
var stlines []string
for i, t := range c.structTypes {
stlines = append(stlines, fmt.Sprintf("struct S%d {", i))
for j, st := range t.Sub {
stlines = append(stlines, fmt.Sprintf("\t%s;", c.metalVarDecl(p, &st, fmt.Sprintf("M%d", j), false, false)))
}
stlines = append(stlines, "};")
}
ls = strings.ReplaceAll(ls, "{{.Structs}}", strings.Join(stlines, "\n"))
} else {
ls = strings.ReplaceAll(ls, "{{.Structs}}", "")
}
nls := regexp.MustCompile(`\n\n+`)
ls = nls.ReplaceAllString(ls, "\n\n")
ls = strings.TrimSpace(ls) + "\n"
return ls
}
func (c *compileContext) metalType(p *shaderir.Program, t *shaderir.Type, packed bool, ref bool) string {
switch t.Main {
case shaderir.None:
return "void"
case shaderir.Struct:
return c.structName(p, t)
default:
return typeString(t, packed, ref)
}
}
func (c *compileContext) metalVarDecl(p *shaderir.Program, t *shaderir.Type, varname string, packed bool, ref bool) string {
switch t.Main {
case shaderir.None:
return "?(none)"
case shaderir.Struct:
s := c.structName(p, t)
if ref {
s += "&"
}
return fmt.Sprintf("%s %s", s, varname)
default:
t := typeString(t, packed, ref)
return fmt.Sprintf("%s %s", t, varname)
}
}
func (c *compileContext) metalVarInit(p *shaderir.Program, t *shaderir.Type) string {
switch t.Main {
case shaderir.None:
return "?(none)"
case shaderir.Array:
return "{}"
case shaderir.Struct:
return "{}"
case shaderir.Bool:
return "false"
case shaderir.Int:
return "0"
case shaderir.Float, shaderir.Vec2, shaderir.Vec3, shaderir.Vec4, shaderir.Mat2, shaderir.Mat3, shaderir.Mat4:
return fmt.Sprintf("%s(0)", basicTypeString(t.Main, false))
default:
t := c.metalType(p, t, false, false)
panic(fmt.Sprintf("?(unexpected type: %s)", t))
}
}
func (c *compileContext) metalFunc(p *shaderir.Program, f *shaderir.Func, prototype bool) []string {
var args []string
// Uniform variables and texture variables. In Metal, non-const global variables are not available.
for i, u := range p.Uniforms {
args = append(args, "constant "+c.metalVarDecl(p, &u, fmt.Sprintf("U%d", i), false, true))
}
for i := 0; i < p.TextureNum; i++ {
args = append(args, fmt.Sprintf("texture2d<float> T%d", i))
}
var idx int
for _, t := range f.InParams {
args = append(args, c.metalVarDecl(p, &t, fmt.Sprintf("l%d", idx), false, false))
idx++
}
for _, t := range f.OutParams {
args = append(args, "thread "+c.metalVarDecl(p, &t, fmt.Sprintf("l%d", idx), false, true))
idx++
}
argsstr := "void"
if len(args) > 0 {
argsstr = strings.Join(args, ", ")
}
t := c.metalType(p, &f.Return, false, false)
sig := fmt.Sprintf("%s F%d(%s)", t, f.Index, argsstr)
var lines []string
if prototype {
lines = append(lines, fmt.Sprintf("%s;", sig))
return lines
}
lines = append(lines, fmt.Sprintf("%s {", sig))
lines = append(lines, c.metalBlock(p, f.Block, f.Block, 0)...)
lines = append(lines, "}")
return lines
}
func constantToNumberLiteral(t shaderir.ConstType, v constant.Value) string {
switch t {
case shaderir.ConstTypeNone:
if v.Kind() == constant.Bool {
if constant.BoolVal(v) {
return "true"
}
return "false"
}
fallthrough
case shaderir.ConstTypeFloat:
if i := constant.ToInt(v); i.Kind() == constant.Int {
x, _ := constant.Int64Val(i)
return fmt.Sprintf("%d.0", x)
}
if i := constant.ToFloat(v); i.Kind() == constant.Float {
x, _ := constant.Float64Val(i)
return fmt.Sprintf("%.10e", x)
}
case shaderir.ConstTypeInt:
if i := constant.ToInt(v); i.Kind() == constant.Int {
x, _ := constant.Int64Val(i)
return fmt.Sprintf("%d", x)
}
}
return fmt.Sprintf("?(unexpected literal: %s)", v)
}
func localVariableName(p *shaderir.Program, topBlock *shaderir.Block, idx int) string {
switch topBlock {
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case p.VertexFunc.Block:
na := len(p.Attributes)
nv := len(p.Varyings)
switch {
case idx < na:
return fmt.Sprintf("attributes[vid].M%d", idx)
case idx == na:
return fmt.Sprintf("%s.Position", vertexOut)
case idx < na+nv+1:
return fmt.Sprintf("%s.M%d", vertexOut, idx-na-1)
default:
return fmt.Sprintf("l%d", idx-(na+nv+1))
}
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case p.FragmentFunc.Block:
nv := len(p.Varyings)
switch {
case idx == 0:
return fmt.Sprintf("varyings.Position")
case idx < nv+1:
return fmt.Sprintf("varyings.M%d", idx-1)
case idx == nv+1:
return fragmentOut
default:
return fmt.Sprintf("l%d", idx-(nv+2))
}
default:
return fmt.Sprintf("l%d", idx)
}
}
func (c *compileContext) initVariable(p *shaderir.Program, topBlock, block *shaderir.Block, index int, decl bool, level int) []string {
idt := strings.Repeat("\t", level+1)
name := localVariableName(p, topBlock, index)
t := p.LocalVariableType(topBlock, block, index)
var lines []string
if decl {
lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, c.metalVarDecl(p, &t, name, false, false), c.metalVarInit(p, &t)))
} else {
lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, name, c.metalVarInit(p, &t)))
}
return lines
}
func (c *compileContext) metalBlock(p *shaderir.Program, topBlock, block *shaderir.Block, level int) []string {
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if block == nil {
return nil
}
idt := strings.Repeat("\t", level+1)
var lines []string
for i, t := range block.LocalVars {
// The type is None e.g., when the variable is a for-loop counter.
if t.Main != shaderir.None {
lines = append(lines, c.initVariable(p, topBlock, block, block.LocalVarIndexOffset+i, true, level)...)
}
}
var metalExpr func(e *shaderir.Expr) string
metalExpr = func(e *shaderir.Expr) string {
switch e.Type {
case shaderir.NumberExpr:
return constantToNumberLiteral(e.ConstType, e.Const)
case shaderir.UniformVariable:
return fmt.Sprintf("U%d", e.Index)
case shaderir.TextureVariable:
return fmt.Sprintf("T%d", e.Index)
case shaderir.LocalVariable:
return localVariableName(p, topBlock, e.Index)
case shaderir.StructMember:
return fmt.Sprintf("M%d", e.Index)
case shaderir.BuiltinFuncExpr:
return builtinFuncString(e.BuiltinFunc)
case shaderir.SwizzlingExpr:
if !shaderir.IsValidSwizzling(e.Swizzling) {
return fmt.Sprintf("?(unexpected swizzling: %s)", e.Swizzling)
}
return e.Swizzling
case shaderir.FunctionExpr:
return fmt.Sprintf("F%d", e.Index)
case shaderir.Unary:
var op string
switch e.Op {
case shaderir.Add, shaderir.Sub, shaderir.NotOp:
op = string(e.Op)
default:
op = fmt.Sprintf("?(unexpected op: %s)", string(e.Op))
}
return fmt.Sprintf("%s(%s)", op, metalExpr(&e.Exprs[0]))
case shaderir.Binary:
return fmt.Sprintf("(%s) %s (%s)", metalExpr(&e.Exprs[0]), e.Op, metalExpr(&e.Exprs[1]))
case shaderir.Selection:
return fmt.Sprintf("(%s) ? (%s) : (%s)", metalExpr(&e.Exprs[0]), metalExpr(&e.Exprs[1]), metalExpr(&e.Exprs[2]))
case shaderir.Call:
callee := e.Exprs[0]
var args []string
if callee.Type != shaderir.BuiltinFuncExpr {
for i := range p.Uniforms {
args = append(args, fmt.Sprintf("U%d", i))
}
for i := 0; i < p.TextureNum; i++ {
args = append(args, fmt.Sprintf("T%d", i))
}
}
for _, exp := range e.Exprs[1:] {
args = append(args, metalExpr(&exp))
}
if callee.Type == shaderir.BuiltinFuncExpr && callee.BuiltinFunc == shaderir.Texture2DF {
return fmt.Sprintf("%s.sample(texture_sampler, %s)", args[0], strings.Join(args[1:], ", "))
}
return fmt.Sprintf("%s(%s)", metalExpr(&callee), strings.Join(args, ", "))
case shaderir.FieldSelector:
return fmt.Sprintf("(%s).%s", metalExpr(&e.Exprs[0]), metalExpr(&e.Exprs[1]))
case shaderir.Index:
return fmt.Sprintf("(%s)[%s]", metalExpr(&e.Exprs[0]), metalExpr(&e.Exprs[1]))
default:
return fmt.Sprintf("?(unexpected expr: %d)", e.Type)
}
}
for _, s := range block.Stmts {
switch s.Type {
case shaderir.ExprStmt:
lines = append(lines, fmt.Sprintf("%s%s;", idt, metalExpr(&s.Exprs[0])))
case shaderir.BlockStmt:
lines = append(lines, idt+"{")
lines = append(lines, c.metalBlock(p, topBlock, s.Blocks[0], level+1)...)
lines = append(lines, idt+"}")
case shaderir.Assign:
lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, metalExpr(&s.Exprs[0]), metalExpr(&s.Exprs[1])))
case shaderir.Init:
init := true
if topBlock == p.VertexFunc.Block {
// In the vertex function, varying values are the output parameters.
// These values are represented as a struct and not needed to be initialized.
na := len(p.Attributes)
nv := len(p.Varyings)
if s.InitIndex < na+nv+1 {
init = false
}
}
if init {
lines = append(lines, c.initVariable(p, topBlock, block, s.InitIndex, false, level)...)
}
case shaderir.If:
lines = append(lines, fmt.Sprintf("%sif (%s) {", idt, metalExpr(&s.Exprs[0])))
lines = append(lines, c.metalBlock(p, topBlock, s.Blocks[0], level+1)...)
if len(s.Blocks) > 1 {
lines = append(lines, fmt.Sprintf("%s} else {", idt))
lines = append(lines, c.metalBlock(p, topBlock, s.Blocks[1], level+1)...)
}
lines = append(lines, fmt.Sprintf("%s}", idt))
case shaderir.For:
var ct shaderir.ConstType
switch s.ForVarType.Main {
case shaderir.Int:
ct = shaderir.ConstTypeInt
case shaderir.Float:
ct = shaderir.ConstTypeFloat
}
v := localVariableName(p, topBlock, s.ForVarIndex)
var delta string
switch val, _ := constant.Float64Val(s.ForDelta); val {
case 0:
delta = fmt.Sprintf("?(unexpected delta: %v)", s.ForDelta)
case 1:
delta = fmt.Sprintf("%s++", v)
case -1:
delta = fmt.Sprintf("%s--", v)
default:
d := s.ForDelta
if val > 0 {
delta = fmt.Sprintf("%s += %s", v, constantToNumberLiteral(ct, d))
} else {
d = constant.UnaryOp(token.SUB, d, 0)
delta = fmt.Sprintf("%s -= %s", v, constantToNumberLiteral(ct, d))
}
}
var op string
switch s.ForOp {
case shaderir.LessThanOp, shaderir.LessThanEqualOp, shaderir.GreaterThanOp, shaderir.GreaterThanEqualOp, shaderir.EqualOp, shaderir.NotEqualOp:
op = string(s.ForOp)
default:
op = fmt.Sprintf("?(unexpected op: %s)", string(s.ForOp))
}
t := s.ForVarType
init := constantToNumberLiteral(ct, s.ForInit)
end := constantToNumberLiteral(ct, s.ForEnd)
ts := typeString(&t, false, false)
lines = append(lines, fmt.Sprintf("%sfor (%s %s = %s; %s %s %s; %s) {", idt, ts, v, init, v, op, end, delta))
lines = append(lines, c.metalBlock(p, topBlock, s.Blocks[0], level+1)...)
lines = append(lines, fmt.Sprintf("%s}", idt))
case shaderir.Continue:
lines = append(lines, idt+"continue;")
case shaderir.Break:
lines = append(lines, idt+"break;")
case shaderir.Return:
switch {
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case topBlock == p.VertexFunc.Block:
lines = append(lines, fmt.Sprintf("%sreturn %s;", idt, vertexOut))
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case topBlock == p.FragmentFunc.Block:
lines = append(lines, fmt.Sprintf("%sreturn %s;", idt, fragmentOut))
case len(s.Exprs) == 0:
lines = append(lines, idt+"return;")
default:
lines = append(lines, fmt.Sprintf("%sreturn %s;", idt, metalExpr(&s.Exprs[0])))
}
case shaderir.Discard:
lines = append(lines, idt+"discard;")
default:
lines = append(lines, fmt.Sprintf("%s?(unexpected stmt: %d)", idt, s.Type))
}
}
return lines
}