Patch #1121337 (CGA rendering in early LEC titles).

Differences against patch:
  o Updated documentation
  o Fixed text colors
  o Implemented Hercules dithering

Ditherers are based on loom ega and monkey ega, so for zak and mm they're
wrong, i.e. these games look better than with original ditherers.

TODO:
  Proper ditherers for zak & MM
  EGA ditherers for VGA SCUMM v5 games

svn-id: r16816

2 files changed, 73 insertions, 1 deletions

diff --git a/common/util.cpp b/common/util.cpp
index eb63e16a68..f4d5c91779 100644
--- a/common/util.cpp
+++ b/common/util.cpp
@@ -219,5 +219,47 @@ const char *getPlatformDescription(Platform id) {
 }
 
 
+#pragma mark -
+
+
+const RenderModeDescription g_renderModes[] = {
+	{"hercules", "Hercules", kRenderHerc},
+	{"cga", "CGA", kRenderCGA},
+	{"ega", "EGA", kRenderEGA},
+	{0, 0, kRenderDefault}
+};
+
+RenderMode parseRenderMode(const String &str) {
+	if (str.isEmpty())
+		return kRenderDefault;
+
+	const char *s = str.c_str();
+	const RenderModeDescription *l = g_renderModes;
+	for (; l->code; ++l) {
+		if (!scumm_stricmp(l->code, s))
+			return l->id;
+	}
+
+	return kRenderDefault;
+}
+
+const char *getRenderModeCode(RenderMode id) {
+	const RenderModeDescription *l = g_renderModes;
+	for (; l->code; ++l) {
+		if (l->id == id)
+			return l->code;
+	}
+	return 0;
+}
+
+const char *getRenderModeDescription(RenderMode id) {
+	const RenderModeDescription *l = g_renderModes;
+	for (; l->code; ++l) {
+		if (l->id == id)
+			return l->description;
+	}
+	return 0;
+}
+
 
 }	// End of namespace Common
diff --git a/common/util.h b/common/util.h
index 8813fc9d8b..173f2bf835 100644
--- a/common/util.h
+++ b/common/util.h
@@ -147,12 +147,42 @@ struct PlatformDescription {
 
 extern const PlatformDescription g_platforms[];
 
-
 /** Convert a string containing a platform name into a Platform enum value. */
 extern Platform parsePlatform(const String &str);
 extern const char *getPlatformCode(Platform id);
 extern const char *getPlatformDescription(Platform id);
 
+/** 
+ * List of render modes. It specifies which original graphics mode
+ * to use. Some targets used postprocessing dithering routines for
+ * reducing color depth of final image which let it to be rendered on
+ * such low-level adapters as CGA or Hercules.
+ */
+enum RenderMode {
+	kRenderDefault = -1,
+	kRenderEGA = 1,
+	kRenderCGA = 2,
+	kRenderHerc = 3
+};
+
+enum HerculesDimesnions {
+	kHercW = 720,
+	kHercH = 350
+};
+
+struct RenderModeDescription {
+	const char *code;
+	const char *description;
+	Common::RenderMode id;
+};
+
+extern const RenderModeDescription g_renderModes[];
+
+/** Convert a string containing a render mode name into a RenderingMode enum value. */
+extern RenderMode parseRenderMode(const String &str);
+extern const char *getRenderModeCode(RenderMode id);
+extern const char *getRenderModeDescription(RenderMode id);
+
 }	// End of namespace Common