ebiten/internal/shaderir/glsl.go
2020-05-17 17:06:21 +09:00

329 lines
8.9 KiB
Go

// 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 shaderir
import (
"fmt"
"strings"
)
func isValidSwizzling(s string) bool {
if len(s) < 1 || 4 < len(s) {
return false
}
const (
xyzw = "xyzw"
rgba = "rgba"
strq = "strq"
)
switch {
case strings.IndexByte(xyzw, s[0]) >= 0:
for _, c := range s {
if strings.IndexRune(xyzw, c) == -1 {
return false
}
}
return true
case strings.IndexByte(rgba, s[0]) >= 0:
for _, c := range s {
if strings.IndexRune(rgba, c) == -1 {
return false
}
}
return true
case strings.IndexByte(strq, s[0]) >= 0:
for _, c := range s {
if strings.IndexRune(strq, c) == -1 {
return false
}
}
return true
}
return false
}
func (p *Program) structName(t *Type) string {
if t.Main != Struct {
panic("shaderir: the given type at structName must be a struct")
}
s := t.serialize()
if n, ok := p.structNames[s]; ok {
return n
}
n := fmt.Sprintf("S%d", len(p.structNames))
p.structNames[s] = n
p.structTypes = append(p.structTypes, *t)
return n
}
func (p *Program) Glsl() string {
p.structNames = map[string]string{}
p.structTypes = nil
var lines []string
for i, t := range p.Uniforms {
lines = append(lines, fmt.Sprintf("uniform %s;", p.glslVarDecl(&t, fmt.Sprintf("U%d", i))))
}
for i, t := range p.Attributes {
lines = append(lines, fmt.Sprintf("attribute %s;", p.glslVarDecl(&t, fmt.Sprintf("A%d", i))))
}
for i, t := range p.Varyings {
lines = append(lines, fmt.Sprintf("varying %s;", p.glslVarDecl(&t, fmt.Sprintf("V%d", i))))
}
for _, f := range p.Funcs {
lines = append(lines, p.glslFunc(&f)...)
}
// Vertex func
if len(p.VertexFunc.Block.Stmts) > 0 {
lines = append(lines, "")
lines = append(lines, "#if defined(COMPILING_VERTEX_SHADER)")
lines = append(lines, "void main(void) {")
lines = append(lines, p.glslBlock(&p.VertexFunc.Block, 0, 0)...)
lines = append(lines, "}")
lines = append(lines, "#endif")
}
// Fragment func
if len(p.FragmentFunc.Block.Stmts) > 0 {
lines = append(lines, "")
lines = append(lines, "#if defined(COMPILING_FRAGMENT_SHADER)")
lines = append(lines, "void main(void) {")
lines = append(lines, p.glslBlock(&p.FragmentFunc.Block, 0, 0)...)
lines = append(lines, "}")
lines = append(lines, "#endif")
}
var stLines []string
for i, t := range p.structTypes {
stLines = append(stLines, fmt.Sprintf("struct S%d {", i))
for j, st := range t.Sub {
stLines = append(stLines, fmt.Sprintf("\t%s;", p.glslVarDecl(&st, fmt.Sprintf("M%d", j))))
}
stLines = append(stLines, "};")
}
lines = append(stLines, lines...)
return strings.Join(lines, "\n") + "\n"
}
func (p *Program) glslType(t *Type) string {
switch t.Main {
case None:
return "void"
case Array:
panic("not implemented")
case Struct:
return p.structName(t)
default:
return t.Main.Glsl()
}
}
func (p *Program) glslVarDecl(t *Type, varname string) string {
switch t.Main {
case None:
return "?(none)"
case Array:
panic("not implemented")
case Struct:
return fmt.Sprintf("%s %s", p.structName(t), varname)
default:
return fmt.Sprintf("%s %s", t.Main.Glsl(), varname)
}
}
func (p *Program) glslFunc(f *Func) []string {
var args []string
var idx int
for _, t := range f.InParams {
args = append(args, "in "+p.glslVarDecl(&t, fmt.Sprintf("l%d", idx)))
idx++
}
for _, t := range f.InOutParams {
args = append(args, "inout "+p.glslVarDecl(&t, fmt.Sprintf("l%d", idx)))
idx++
}
for _, t := range f.OutParams {
args = append(args, "out "+p.glslVarDecl(&t, fmt.Sprintf("l%d", idx)))
idx++
}
argsstr := "void"
if len(args) > 0 {
argsstr = strings.Join(args, ", ")
}
var lines []string
lines = append(lines, fmt.Sprintf("%s F%d(%s) {", p.glslType(&f.Return), f.Index, argsstr))
lines = append(lines, p.glslBlock(&f.Block, 0, idx)...)
lines = append(lines, "}")
return lines
}
func (p *Program) glslBlock(b *Block, level int, localVarIndex int) []string {
idt := strings.Repeat("\t", level+1)
var lines []string
for _, t := range b.LocalVars {
lines = append(lines, fmt.Sprintf("%s%s;", idt, p.glslVarDecl(&t, fmt.Sprintf("l%d", localVarIndex))))
localVarIndex++
}
var glslExpr func(e *Expr) string
glslExpr = func(e *Expr) string {
switch e.Type {
case IntExpr:
return fmt.Sprintf("%d", e.Int)
case FloatExpr:
return fmt.Sprintf("%.9e", e.Float)
case UniformVariable:
return fmt.Sprintf("U%d", e.Index)
case LocalVariable:
idx := e.Index
switch b {
case &p.VertexFunc.Block:
na := len(p.Attributes)
nv := len(p.Varyings)
switch {
case idx < na:
return fmt.Sprintf("A%d", idx)
case idx < na+nv:
return fmt.Sprintf("V%d", idx-na)
case idx == na+nv:
return "gl_Position"
default:
return fmt.Sprintf("l%d", idx-(na+nv+1))
}
case &p.FragmentFunc.Block:
nv := len(p.Varyings)
switch {
case idx < nv:
return fmt.Sprintf("V%d", idx)
case idx == nv:
return "gl_FragCoord"
default:
return fmt.Sprintf("l%d", idx-(nv+1))
}
default:
return fmt.Sprintf("l%d", idx)
}
case StructMember:
return fmt.Sprintf("M%d", e.Index)
case BuiltinFuncExpr:
return string(e.BuiltinFunc)
case SwizzlingExpr:
if !isValidSwizzling(e.Swizzling) {
return fmt.Sprintf("?(unexpected swizzling: %s)", e.Swizzling)
}
return e.Swizzling
case FunctionExpr:
return fmt.Sprintf("F%d", e.Index)
case Unary:
var op string
switch e.Op {
case Add, Sub, Neg:
op = string(e.Op)
default:
op = fmt.Sprintf("?(unexpected op: %s)", string(e.Op))
}
return fmt.Sprintf("%s(%s)", op, glslExpr(&e.Exprs[0]))
case Binary:
return fmt.Sprintf("(%s) %s (%s)", glslExpr(&e.Exprs[0]), e.Op, glslExpr(&e.Exprs[1]))
case Selection:
return fmt.Sprintf("(%s) ? (%s) : (%s)", glslExpr(&e.Exprs[0]), glslExpr(&e.Exprs[1]), glslExpr(&e.Exprs[2]))
case Call:
var args []string
for _, exp := range e.Exprs[1:] {
args = append(args, glslExpr(&exp))
}
return fmt.Sprintf("(%s)(%s)", glslExpr(&e.Exprs[0]), strings.Join(args, ", "))
case FieldSelector:
return fmt.Sprintf("(%s).%s", glslExpr(&e.Exprs[0]), glslExpr(&e.Exprs[1]))
case Index:
return fmt.Sprintf("(%s)[%s]", glslExpr(&e.Exprs[0]), glslExpr(&e.Exprs[1]))
default:
return fmt.Sprintf("?(unexpected expr: %d)", e.Type)
}
}
for _, s := range b.Stmts {
switch s.Type {
case ExprStmt:
lines = append(lines, fmt.Sprintf("%s%s;", idt, glslExpr(&s.Exprs[0])))
case BlockStmt:
lines = append(lines, idt+"{")
lines = append(lines, p.glslBlock(&s.Blocks[0], level+1, localVarIndex)...)
lines = append(lines, idt+"}")
case Assign:
lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, glslExpr(&s.Exprs[0]), glslExpr(&s.Exprs[1])))
case If:
lines = append(lines, fmt.Sprintf("%sif (%s) {", idt, glslExpr(&s.Exprs[0])))
lines = append(lines, p.glslBlock(&s.Blocks[0], level+1, localVarIndex)...)
if len(s.Blocks) > 1 {
lines = append(lines, fmt.Sprintf("%s} else {", idt))
lines = append(lines, p.glslBlock(&s.Blocks[1], level+1, localVarIndex)...)
}
lines = append(lines, fmt.Sprintf("%s}", idt))
case For:
v := localVarIndex
localVarIndex++
var delta string
switch s.ForDelta {
case 0:
delta = fmt.Sprintf("?(unexpected delta: %d)", s.ForDelta)
case 1:
delta = fmt.Sprintf("l%d++", v)
case -1:
delta = fmt.Sprintf("l%d--", v)
default:
if s.ForDelta > 0 {
delta = fmt.Sprintf("l%d += %d", v, s.ForDelta)
} else {
delta = fmt.Sprintf("l%d -= %d", v, -s.ForDelta)
}
}
var op string
switch s.ForOp {
case LessThanOp, LessThanEqualOp, GreaterThanOp, GreaterThanEqualOp, EqualOp, NotEqualOp:
op = string(s.ForOp)
default:
op = fmt.Sprintf("?(unexpected op: %s)", string(s.ForOp))
}
lines = append(lines, fmt.Sprintf("%sfor (int l%d = %d; l%d %s %d; %s) {", idt, v, s.ForInit, v, op, s.ForEnd, delta))
lines = append(lines, p.glslBlock(&s.Blocks[0], level+1, localVarIndex)...)
lines = append(lines, fmt.Sprintf("%s}", idt))
case Continue:
lines = append(lines, idt+"continue;")
case Break:
lines = append(lines, idt+"break;")
case Return:
if len(s.Exprs) == 0 {
lines = append(lines, idt+"return;")
} else {
lines = append(lines, fmt.Sprintf("%sreturn %s;", idt, glslExpr(&s.Exprs[0])))
}
case Discard:
lines = append(lines, idt+"discard;")
default:
lines = append(lines, fmt.Sprintf("%s?(unexpected stmt: %d)", idt, s.Type))
}
}
return lines
}