From 80d0e1c3367628a3048f68e1514db399ded9ae03 Mon Sep 17 00:00:00 2001
From: King_DuckZ <king_duckz@gmx.com>
Date: Fri, 10 Feb 2017 15:40:26 +0000
Subject: [PATCH] Add test for intersection and fix data in raytracer test.

---
 src/gamelib/grid_raytrace.cpp |  2 +-
 test/unit/grid_raytrace.cpp   | 54 ++++++++++++++++++++++++++++-------
 2 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/src/gamelib/grid_raytrace.cpp b/src/gamelib/grid_raytrace.cpp
index 862e0db..3309bf7 100644
--- a/src/gamelib/grid_raytrace.cpp
+++ b/src/gamelib/grid_raytrace.cpp
@@ -71,7 +71,7 @@ namespace curry {
 			assert(not (std::abs(r_cross_s) <= FLT_EPSILON));
 			const auto inv_r_cross_s = 1.0f / r_cross_s;
 			const auto t = cross(q - p, s) * inv_r_cross_s;
-			const auto u = cross(q - p, r) * inv_r_cross_s;
+			//const auto u = cross(q - p, r) * inv_r_cross_s;
 
 			return t;
 			//if (0.0f <= t and t <= 1.0f and 0.0f <= u and u <= 1.0f)
diff --git a/test/unit/grid_raytrace.cpp b/test/unit/grid_raytrace.cpp
index 43970f4..5fbd6a9 100644
--- a/test/unit/grid_raytrace.cpp
+++ b/test/unit/grid_raytrace.cpp
@@ -24,7 +24,7 @@
 #include "tileproperty.hpp"
 #include <vector>
 
-TEST_CASE ("Check that 2D raytracing works", "[raytracing, geometry]") {
+TEST_CASE ("Check that 2D raytracing works", "[raytracing][geometry]") {
 	using curry::for_each_voxel_under_segment;
 	using curry::vec2us;
 	using curry::vec2f;
@@ -32,16 +32,16 @@ TEST_CASE ("Check that 2D raytracing works", "[raytracing, geometry]") {
 
 	curry::WorldGrid world(vec2us(64));
 	world.set_layers(vec2us(10, 10), std::vector<std::vector<curry::TileIndex>>( {{
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 	}}));
 	world.set_tile_properties(std::vector<curry::TileProperty>({ curry::TileProperty() }));
 
@@ -74,3 +74,35 @@ TEST_CASE ("Check that 2D raytracing works", "[raytracing, geometry]") {
 		CHECK(expected == diagonal);
 	}
 }
+
+TEST_CASE ("Check that segment intersection code used by the raytracing code works", "[geometry][intersection]") {
+	using curry::vec2f;
+	using curry::segment_intersection;
+
+	{
+		//Two segments crossing at <0, 0>
+		const vec2f a0(-1.0f, 0.0f);
+		const vec2f a1(2.0f, 0.0f);
+		const vec2f b0(0.0f, 1.0f);
+		const vec2f b1(0.0f, -2.0f);
+
+		const float t1 = segment_intersection(a0, a1, b0, b1);
+		CHECK(0.5f == t1);
+		CHECK(vec2f(0.0f) == a0 + t1 * a1);
+		const float t2 = segment_intersection(b0, b1, a0, a1);
+		CHECK(0.5f == t2);
+	}
+
+	{
+		//a diagonal segment starting off from a vertical segment
+		const vec2f a0(-1.0f, 0.0f);
+		const vec2f a1(3.0f, 2.0f);
+		const vec2f b0(-1.0f, 1.0f);
+		const vec2f b1(0.0f, -2.0f);
+
+		const float t1 = segment_intersection(a0, a1, b0, b1);
+		CHECK(0.0f == t1);
+		const float t2 = segment_intersection(b0, b1, a0, a1);
+		CHECK(0.5f == t2);
+	}
+}