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author | Dan Goodliffe <dan.goodliffe@octal.co.uk> | 2022-12-13 12:14:43 +0000 |
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committer | Dan Goodliffe <dan.goodliffe@octal.co.uk> | 2022-12-13 12:14:43 +0000 |
commit | c20c5167510758353d5a62cfff24fd5494b9c5a4 (patch) | |
tree | 2b249e1c94fe26593ea22972b486553da8b57bda /gfx/gl | |
parent | Calculate an accurate up vector for the camera (diff) | |
download | ilt-c20c5167510758353d5a62cfff24fd5494b9c5a4.tar.bz2 ilt-c20c5167510758353d5a62cfff24fd5494b9c5a4.tar.xz ilt-c20c5167510758353d5a62cfff24fd5494b9c5a4.zip |
Add Camera method to get the extents of the view frustrum at some distance
Diffstat (limited to 'gfx/gl')
-rw-r--r-- | gfx/gl/camera.cpp | 18 | ||||
-rw-r--r-- | gfx/gl/camera.h | 2 |
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:
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