From 4f0a1df3c1b49bb9325cd528233ac77ff779a328 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Wed, 2 Jan 2013 16:48:13 +0900
Subject: [PATCH] Implement sky tracing.

Again, this is from Jardrup's light tool. Sun data is not yet parsed, nor
are any sun lighting calculations done.
---
 tools/qflight/include/light.h |  1 +
 tools/qflight/source/trace.c  | 22 +++++++++++++++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/tools/qflight/include/light.h b/tools/qflight/include/light.h
index 436a660b7..184883746 100644
--- a/tools/qflight/include/light.h
+++ b/tools/qflight/include/light.h
@@ -96,6 +96,7 @@ extern float minlights[MAX_MAP_FACES];
 
 void LoadNodes (const char *file);
 qboolean TestLine (lightinfo_t *l, vec3_t start, vec3_t stop);
+qboolean TestSky (lightinfo_t *l, vec3_t start, vec3_t stop);
 
 void LightFace (lightinfo_t *l, int surfnum);
 void LightLeaf (dleaf_t *leaf);
diff --git a/tools/qflight/source/trace.c b/tools/qflight/source/trace.c
index 39d17ceb0..68f06f852 100644
--- a/tools/qflight/source/trace.c
+++ b/tools/qflight/source/trace.c
@@ -142,8 +142,8 @@ MakeTnodes (dmodel_t *bm)
 #define TESTLINESTATE_EMPTY 1
 #define TESTLINESTATE_SOLID 2
 
-qboolean
-TestLine (lightinfo_t *l, vec3_t start, vec3_t end)
+static qboolean
+TestLineOrSky (lightinfo_t *l, vec3_t start, vec3_t end, qboolean sky_test)
 {
 	vec_t       front, back;
 	vec3_t      frontpt, backpt;
@@ -161,6 +161,8 @@ TestLine (lightinfo_t *l, vec3_t start, vec3_t end)
 
 	while (1) {
 		while (node < 0) {
+			if (sky_test && node == CONTENTS_SKY)
+				return true;
 			if (node != CONTENTS_SOLID)
 				empty = 1;
 			else if (empty) {
@@ -171,7 +173,7 @@ TestLine (lightinfo_t *l, vec3_t start, vec3_t end)
 
 			// pop up the stack for a back side
 			if (tstack-- == tracestack)
-				return true;
+				return !sky_test;
 
 			// set the hit point for this plane
 			VectorCopy (backpt, frontpt);
@@ -219,3 +221,17 @@ TestLine (lightinfo_t *l, vec3_t start, vec3_t end)
 		node = tnode->children[side];
 	}
 }
+
+qboolean
+TestLine (lightinfo_t *l, vec3_t start, vec3_t stop)
+{
+	return TestLineOrSky (l, start, stop, false);
+}
+
+qboolean
+TestSky (lightinfo_t *l, vec3_t start, vec3_t dir)
+{
+	vec3_t      stop;
+	VectorAdd (dir, start, stop);
+	return TestLineOrSky (l, start, stop, true);
+}