From 5cd3cfe5485390d8412b10a0e47d3be45bb22f3c Mon Sep 17 00:00:00 2001
From: Stefano Musumeci <subr3v@gmail.com>
Date: Mon, 11 Aug 2014 17:24:21 +0200
Subject: [PATCH] TINYGL: Fixed a bug with triangle strip rendering.

---
 graphics/tinygl/zdirtyrect.cpp | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/graphics/tinygl/zdirtyrect.cpp b/graphics/tinygl/zdirtyrect.cpp
index bd6256cfd50..1edf870cc1d 100644
--- a/graphics/tinygl/zdirtyrect.cpp
+++ b/graphics/tinygl/zdirtyrect.cpp
@@ -352,9 +352,18 @@ void RasterizationDrawCall::execute(bool restoreState) const {
 		}
 		break;
 	case TGL_TRIANGLE_STRIP:
-		for(int i = 0; i < cnt; i += 2) {
-			gl_draw_triangle(c, &c->vertex[i], &c->vertex[i + 1], &c->vertex[i + 2]);
-			gl_draw_triangle(c, &c->vertex[i + 2], &c->vertex[i + 1], &c->vertex[i + 3]);
+		while (cnt >= 3) {
+			// needed to respect triangle orientation
+			switch (cnt & 1) {
+			case 0:
+				gl_draw_triangle(c, &c->vertex[2], &c->vertex[1], &c->vertex[0]);
+				break;
+			case 1:
+				gl_draw_triangle(c, &c->vertex[0], &c->vertex[1], &c->vertex[2]);
+				break;
+			}
+			cnt--;
+			c->vertex++;
 		}
 		break;
 	case TGL_TRIANGLE_FAN: