GPU Pro 6

526 VII 3D Engine Design

TIntermLoop(ELoopWhile)

“while (i < 4) {

…

}”

TIntermBinary(EOpLessan)

…

Condition

Body

Left

TIntermSymbol(“i”) TIntermConstantUnion(4)

Right

Figure 3.1. Exampleofparsingastringintoanabstractsyntaxtree.

makes it relatively easy to update the grammar. The GLSL ES specification

conveniently lists the entire grammar in its appendix. Also, 3DLab’s code was

clearly intended for assembly or binary output, but the AST traverser archi-

tecture is nicely object-oriented to allow for alternative implementations. The

biggest change that was required for outputting a high-level language was to

not just perform an implementation-dependent action ...