shaderir: Add for-loop

internal/shaderir/glsl.go

@@ -171,7 +171,20 @@ func (p *Program) glslBlock(b *Block, f *Func, level int, localVarIndex int) []s
 			}
 			lines = append(lines, fmt.Sprintf("%s}", idt))
 		case For:
-			panic("not implemented")
+			v := localVarIndex
+			localVarIndex++
+			var delta string
+			switch s.ForDelta {
+			case 1:
+				delta = fmt.Sprintf("l%d++", v)
+			case -1:
+				delta = fmt.Sprintf("l%d--", v)
+			default:
+				delta = fmt.Sprintf("l%d += %d", v, s.ForDelta)
+			}
+			lines = append(lines, fmt.Sprintf("%sfor (int l%d = %d; l%d < %d; %s) {", idt, v, s.ForInit, v, s.ForEnd, delta))
+			lines = append(lines, p.glslBlock(&s.Blocks[0], f, level+1, localVarIndex)...)
+			lines = append(lines, fmt.Sprintf("%s}", idt))
 		case Continue:
 			lines = append(lines, idt+"continue;")
 		case Break:

internal/shaderir/ir_test.go

@@ -49,6 +49,16 @@ func ifStmt(cond Expr, block Block, elseBlock Block) Stmt {
 	}
 }
 
+func forStmt(init, end, delta int, block Block) Stmt {
+	return Stmt{
+		Type:     For,
+		Blocks:   []Block{block},
+		ForInit:  init,
+		ForEnd:   end,
+		ForDelta: delta,
+	}
+}
+
 func numericExpr(value float64) Expr {
 	return Expr{
 		Type: Numeric,
@@ -308,6 +318,43 @@ varying vec3 V0;`,
 	} else {
 		l2 = l1;
 	}
+}`,
+		},
+		{
+			Name: "FuncFor",
+			Program: Program{
+				Funcs: []Func{
+					{
+						Name: "F0",
+						InParams: []Type{
+							{Main: Float},
+							{Main: Float},
+						},
+						OutParams: []Type{
+							{Main: Float},
+						},
+						Block: block(
+							nil,
+							forStmt(
+								0,
+								100,
+								1,
+								block(
+									nil,
+									assignStmt(
+										varNameExpr(Local, 2),
+										varNameExpr(Local, 0),
+									),
+								),
+							),
+						),
+					},
+				},
+			},
+			Glsl: `void F0(in float l0, in float l1, out float l2) {
+	for (int l3 = 0; l3 < 100; l3++) {
+		l2 = l0;
+	}
 }`,
 		},
 	}

internal/shaderir/program.go

@@ -40,11 +40,12 @@ type Block struct {
 }
 
 type Stmt struct {
-	Type    StmtType
-	Exprs   []Expr
-	Blocks  []Block
-	ForInit Expr
-	ForRest Expr
+	Type     StmtType
+	Exprs    []Expr
+	Blocks   []Block
+	ForInit  int
+	ForEnd   int
+	ForDelta int
 }
 
 type StmtType int

internal/shaderir/type.go

@@ -31,6 +31,8 @@ func (t *Type) serialize() string {
 		return "none"
 	case Bool:
 		return "bool"
+	case Int:
+		return "int"
 	case Float:
 		return "float"
 	case Vec2:
@@ -68,6 +70,7 @@ type BasicType int
 const (
 	None BasicType = iota
 	Bool
+	Int
 	Float
 	Vec2
 	Vec3
@@ -86,6 +89,8 @@ func (t BasicType) Glsl() string {
 		return "?(none)"
 	case Bool:
 		return "bool"
+	case Int:
+		return "Int"
 	case Float:
 		return "float"
 	case Vec2: