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-rw-r--r--gfx/gl/camera.cpp18
-rw-r--r--gfx/gl/camera.h2
2 files changed, 20 insertions, 0 deletions
diff --git a/gfx/gl/camera.cpp b/gfx/gl/camera.cpp
index 69cfe35..31be9a6 100644
--- a/gfx/gl/camera.cpp
+++ b/gfx/gl/camera.cpp
@@ -32,3 +32,21 @@ Camera::upFromForward(const glm::vec3 & forward)
const auto right = glm::cross(forward, ::down);
return glm::cross(forward, right);
}
+
+std::array<glm::vec3, 4>
+Camera::extentsAtDist(const float dist) const
+{
+ const auto depth = -(2.f * (dist - near) * far) / (dist * (near - far)) - 1.f;
+ static constexpr const std::array extents {-1.F, 1.F};
+ std::array<glm::vec3, 4> out {};
+ auto outitr = out.begin();
+ for (auto x : extents) {
+ for (auto y : extents) {
+ const glm::vec4 in {x, y, depth, 1.f};
+
+ const auto out = inverseViewProjection * in;
+ *outitr++ = out / out.w;
+ }
+ }
+ return out;
+}
diff --git a/gfx/gl/camera.h b/gfx/gl/camera.h
index 2d937a0..1ded3e0 100644
--- a/gfx/gl/camera.h
+++ b/gfx/gl/camera.h
@@ -61,6 +61,8 @@ public:
return position;
}
+ std::array<glm::vec3, 4> extentsAtDist(float) const;
+
static glm::vec3 upFromForward(const glm::vec3 & forward);
private: