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authorDan Goodliffe <dan@randomdan.homeip.net>2022-01-07 18:57:08 +0000
committerDan Goodliffe <dan@randomdan.homeip.net>2022-01-07 19:02:01 +0000
commit4ef5c934aacbfce6b3c5502425975edcf61cf0e8 (patch)
tree4f7a64f173dc9bab8467f32b95eb111cf5f0f162
parentDon't invoke CHECK parameters multiple times (diff)
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Initial commit GeoData ray tracer
-rw-r--r--game/geoData.cpp39
-rw-r--r--game/geoData.h13
-rw-r--r--test/test-geo.cpp40
3 files changed, 92 insertions, 0 deletions
diff --git a/game/geoData.cpp b/game/geoData.cpp
index c3fb5dc..4537026 100644
--- a/game/geoData.cpp
+++ b/game/geoData.cpp
@@ -95,6 +95,45 @@ GeoData::positionAt(const glm::vec2 wcoord) const
return wcoord || heightMid;
}
+GeoData::RayTracer::RayTracer(glm::vec2 p0, glm::vec2 p1, float scale) : p {glm::floor(p0)}, d {glm::abs(p1 - p0)}
+{
+ using Limits = std::numeric_limits<typename glm::vec2::value_type>;
+ static_assert(Limits::has_infinity);
+ static constexpr const glm::vec2 inf {Limits::infinity(), -Limits::infinity()};
+
+ auto byAxis = [this, p0, p1, scale](auto axis) {
+ if (d[axis] == 0) {
+ inc[axis] = 0;
+ return inf[axis];
+ }
+ else if (p1[axis] > p0[axis]) {
+ inc[axis] = scale;
+ return (std::floor(p0[axis]) + 1 - p0[axis]) * d[1 - axis];
+ }
+ else {
+ inc[axis] = -scale;
+ return (p0[axis] - std::floor(p0[axis])) * d[1 - axis];
+ }
+ };
+
+ error = byAxis(0);
+ error -= byAxis(1);
+ inc.z = scale;
+}
+
+glm::vec2
+GeoData::RayTracer::next()
+{
+ glm::vec2 cur {p};
+
+ static constexpr const glm::vec2 m {1, -1};
+ const int axis = (error > 0) ? 1 : 0;
+ p[axis] += inc[axis];
+ error += d[1 - axis] * m[axis] * inc.z;
+
+ return cur;
+}
+
unsigned int
GeoData::at(glm::ivec2 coord) const
{
diff --git a/game/geoData.h b/game/geoData.h
index ffb7d64..7bd6ae5 100644
--- a/game/geoData.h
+++ b/game/geoData.h
@@ -32,6 +32,19 @@ public:
[[nodiscard]] float getScale() const;
[[nodiscard]] std::span<const Node> getNodes() const;
+ class RayTracer {
+ public:
+ RayTracer(glm::vec2 p0, glm::vec2 p1, float scale);
+
+ glm::vec2 next();
+
+ private:
+ glm::vec2 p;
+ const glm::vec2 d;
+ float error;
+ glm::vec3 inc;
+ };
+
protected:
Limits limit {}; // Base grid limits first(x,y) -> second(x,y)
glm::uvec2 size {};
diff --git a/test/test-geo.cpp b/test/test-geo.cpp
index 63f192b..f0ed693 100644
--- a/test/test-geo.cpp
+++ b/test/test-geo.cpp
@@ -97,4 +97,44 @@ BOOST_AUTO_TEST_CASE(get_height_at)
BOOST_CHECK_EQUAL(positionAt({2.5F, 2.5F}), glm::vec3(2.5F, 2.5F, 2.5F));
}
+using TestRayTracerData = std::tuple<glm::vec2, glm::vec2, float, std::vector<glm::vec2>>;
+BOOST_DATA_TEST_CASE(raytracer,
+ boost::unit_test::data::make<TestRayTracerData>({
+ {{0, 0}, {0, 0}, 3,
+ {
+ {0, 0},
+ }},
+ {{0, 0}, {4, 5}, 4,
+ {
+ {0, 0},
+ {0, 4},
+ {4, 4},
+ {4, 8},
+ {8, 8},
+ {8, 12},
+ {12, 12},
+ {12, 16},
+ {16, 16},
+ {16, 20},
+ }},
+ {{-1, -1}, {-4, -5}, 5,
+ {
+ {-1, -1},
+ {-6, -1},
+ {-6, -6},
+ {-6, -11},
+ {-11, -11},
+ {-11, -16},
+ {-16, -16},
+ {-16, -21},
+ }},
+ }),
+ start, end, scale, points)
+{
+ GeoData::RayTracer rt {start, end, scale};
+ for (const auto & point : points) {
+ BOOST_CHECK_CLOSE_VEC(point, rt.next());
+ }
+}
+
BOOST_AUTO_TEST_SUITE_END()