1 files changed, 105 insertions, 0 deletions
diff --git a/tools/glsl_preproc/macros.py b/tools/glsl_preproc/macros.py
new file mode 100644
index 0000000..2ba7e21
--- /dev/null
+++ b/tools/glsl_preproc/macros.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+
+import re
+
+from variables import Var
+from templates import *
+from statement import *
+
+PATTERN_PRAGMA  = re.compile(flags=re.VERBOSE, pattern=r'''
+\s*\#\s*pragma\s+               # '#pragma'
+(?P<pragma>(?:                  # pragma name
+    GLSL[PHF]?
+))\s*
+(?P<rest>.*)$                   # rest of line (pragma body)
+''')
+
+# Represents a single #pragma macro
+class Macro(object):
+    PRAGMAS = {
+        'GLSL':  'SH_BUF_BODY',
+        'GLSLP': 'SH_BUF_PRELUDE',
+        'GLSLH': 'SH_BUF_HEADER',
+        'GLSLF': 'SH_BUF_FOOTER',
+    }
+
+    def __init__(self, linenr=0, type='GLSL'):
+        self.linenr = linenr
+        self.buf    = Macro.PRAGMAS[type]
+        self.name   = '_glsl_' + str(linenr)
+        self.body   = []    # list of statements
+        self.last   = None  # previous GLSLBlock (if unterminated)
+        self.vars   = VarSet()
+
+    def needs_single_line(self):
+        if not self.body:
+            return False
+        prev = self.body[-1]
+        return isinstance(prev, BlockStart) and not prev.multiline
+
+    def push_line(self, line):
+        self.vars.merge(line.vars)
+
+        if isinstance(line, GLSLLine):
+            if self.last:
+                self.last.append(line)
+            elif self.needs_single_line():
+                self.body.append(GLSLBlock(line))
+            else:
+                # start new GLSL block
+                self.last = GLSLBlock(line)
+                self.body.append(self.last)
+        else:
+            self.body.append(line)
+            self.last = None
+
+    def render_struct(self):
+        return STRUCT_TEMPLATE.render(macro=self)
+
+    def render_call(self):
+        return CALL_TEMPLATE.render(macro=self)
+
+    def render_fun(self):
+        return FUNCTION_TEMPLATE.render(macro=self, Var=Var)
+
+    # yields output lines
+    @staticmethod
+    def process_file(lines, strip=False):
+        macro = None
+        macros = []
+
+        for linenr, line_orig in enumerate(lines, start=1):
+            line = line_orig.rstrip()
+
+            # Strip leading spaces, due to C indent. Skip first pragma line.
+            if macro and leading_spaces is None:
+                leading_spaces = len(line) - len(line.lstrip())
+
+            # check for start of macro
+            if not macro:
+                leading_spaces = None
+                if result := re.match(PATTERN_PRAGMA, line):
+                    macro = Macro(linenr, type=result['pragma'])
+                    line = result['rest'] # strip pragma prefix
+
+            if macro:
+                if leading_spaces:
+                    line = re.sub(f'^\s{{1,{leading_spaces}}}', '', line)
+                if more_lines := line.endswith('\\'):
+                    line = line[:-1]
+                if statement := Statement.parse(line, strip=strip, linenr=linenr):
+                    macro.push_line(statement)
+                if more_lines:
+                    continue # stay in macro
+                else:
+                    yield macro.render_call()
+                    yield '#line {}\n'.format(linenr + 1)
+                    macros.append(macro)
+                    macro = None
+            else:
+                yield line_orig
+
+        if macros:
+            yield '\n// Auto-generated template functions:'
+        for macro in macros:
+            yield macro.render_fun()