From d99f1249e861c665710c5d8da0351e525c9f2116 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Thu, 17 Oct 2024 03:41:51 +0100
Subject: Better shadowBands sizes

Still a bit arbitrary, but calculated now to scale across the required range
---
 gfx/gl/shadowMapper.cpp | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

(limited to 'gfx/gl/shadowMapper.cpp')

diff --git a/gfx/gl/shadowMapper.cpp b/gfx/gl/shadowMapper.cpp
index 4f7eac1..1b95aa3 100644
--- a/gfx/gl/shadowMapper.cpp
+++ b/gfx/gl/shadowMapper.cpp
@@ -52,13 +52,15 @@ ShadowMapper::ShadowMapper(const TextureAbsCoord & s) :
 	glBindFramebuffer(GL_FRAMEBUFFER, 0);
 }
 
-constexpr std::array<GlobalDistance, ShadowMapper::SHADOW_BANDS + 1> shadowBands {
-		1000,
-		250000,
-		750000,
-		2500000,
-		10000000,
-};
+constexpr auto shadowBands
+		= []<GlobalDistance... ints>(const float scaleFactor, std::integer_sequence<GlobalDistance, ints...>) {
+			  const auto base = 10'000'000 / pow(scaleFactor, sizeof...(ints) - 1);
+			  return std::array {1, static_cast<GlobalDistance>((base * pow(scaleFactor, ints)))...};
+		  }(6.6F, std::make_integer_sequence<GlobalDistance, ShadowMapper::SHADOW_BANDS>());
+
+static_assert(shadowBands.front() == 1);
+static_assert(shadowBands.back() == 10'000'000);
+static_assert(shadowBands.size() == ShadowMapper::SHADOW_BANDS + 1);
 
 std::vector<std::array<RelativePosition3D, 4>>
 ShadowMapper::getBandViewExtents(const Camera & camera, const glm::mat4 & lightViewDir)
-- 
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