From cfdcfbb4aaa1e7c1cad36b9ac3ded6cc02fb1f14 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 2 Mar 2026 20:20:29 +0000
Subject: Calculate an appropriate billboardSize and useMeshClipDist

Removes hard coded arbitrary numbers for 256px sq and 140m.
---
 game/scenary/foliage.cpp | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

(limited to 'game/scenary/foliage.cpp')

diff --git a/game/scenary/foliage.cpp b/game/scenary/foliage.cpp
index cefee9f..680d902 100644
--- a/game/scenary/foliage.cpp
+++ b/game/scenary/foliage.cpp
@@ -1,11 +1,24 @@
 #include "foliage.h"
 #include "gfx/frustum.h"
+#include "gfx/gl/billboardPainter.h"
 #include "gfx/gl/sceneShader.h"
 #include "gfx/gl/shadowMapper.h"
+#include "gfx/gl/shadowStenciller.h"
 #include "gfx/gl/vertexArrayObject.h"
 #include <location.h>
 
 static_assert(std::is_constructible_v<Foliage>);
+constexpr float OBJECT_BILLBOARD_DIVISOR = 64;
+constexpr float ASSUMED_VIEWPORT = 1440;
+constexpr float OVER_SAMPLE_MULTIPLIER = 4; // Use mesh until billboard 1/4 of rendered size
+
+namespace {
+	GLsizei
+	billboardTextureSizeForObject(RelativeDistance objectSize)
+	{
+		return static_cast<GLsizei>(std::pow(2, std::ceil(std::log2(objectSize / OBJECT_BILLBOARD_DIVISOR))));
+	}
+}
 
 std::any
 Foliage::createAt(const Location & position) const
@@ -29,6 +42,12 @@ Foliage::postLoad()
 					instances.bufferName(), 1);
 	VertexArrayObject {instancePointVAO}.addAttribs<LocationVertex, &LocationVertex::position, &LocationVertex::yaw>(
 			instances.bufferName());
+
+	const auto & size = bodyMesh->getDimensions().size;
+	billboardSize = billboardTextureSizeForObject(size);
+	shadowStencil = ShadowStenciller::createStencilTexture(billboardSize, billboardSize);
+	billboard = BillboardPainter::createBillBoardTextures(billboardSize, billboardSize);
+	useMeshClipDist = (ASSUMED_VIEWPORT * OVER_SAMPLE_MULTIPLIER * size) / static_cast<RelativeDistance>(billboardSize);
 }
 
 void
@@ -51,13 +70,13 @@ void
 Foliage::preFrame(const Frustum & frustum, const Frustum & lighting)
 {
 	if (instances.size() > 0) {
-		const auto dims = bodyMesh->getDimensions();
+		const auto & dims = bodyMesh->getDimensions();
 		instancePartitions = instances.partition(
 				[&frustum, &dims](const auto & location) {
 					return frustum.contains(location.position + dims.centre, dims.size);
 				},
-				[&frustum](const auto & location) {
-					return distance(frustum.getPosition(), location.position) < 140'000.F;
+				[&frustum, this](const auto & location) {
+					return distance(frustum.getPosition(), location.position) < useMeshClipDist;
 				},
 				[&lighting, &dims](const auto & location) {
 					return lighting.contains(location.position + dims.centre, dims.size);
-- 
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