From c6b19fe6daaf7f58323b30d5b44e8bfa7bdef149 Mon Sep 17 00:00:00 2001
From: Eric Wasylishen <ewasylishen@gmail.com>
Date: Mon, 14 Nov 2022 00:30:37 -0700
Subject: [PATCH] light: implement -novanilla with -world_units_per_luxel

currently it's required because the non-novanilla path
isn't yet implemented
---
 light/ltface.cc      | 10 ++++++----
 tests/test_ltface.cc | 44 ++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/light/ltface.cc b/light/ltface.cc
index 13cc6e1e..708055c9 100644
--- a/light/ltface.cc
+++ b/light/ltface.cc
@@ -2848,13 +2848,15 @@ void SaveLightmapSurface(const mbsp_t *bsp, mface_t *face, facesup_t *facesup,
         lightofs = out - filebase.data();
     }
 
-    if (facesup) {
+    if (facesup_decoupled && light_options.novanilla.value()) {
+        facesup_decoupled->offset = lightofs;
+        face->lightofs = -1;
+    } else if (facesup_decoupled && !light_options.novanilla.value()) {
+        FError("-world_units_per_luxel currently requires -novanilla");
+    } else if (facesup) {
         facesup->lightofs = lightofs;
     } else {
         face->lightofs = lightofs;
-        if (facesup_decoupled) {
-            facesup_decoupled->offset = lightofs;
-        }
     }
 
     // sanity check that we don't save a lightmap for a non-lightmapped face
diff --git a/tests/test_ltface.cc b/tests/test_ltface.cc
index fee69fd4..8309fccd 100644
--- a/tests/test_ltface.cc
+++ b/tests/test_ltface.cc
@@ -64,7 +64,7 @@ static testresults_t LoadTestmap(const std::filesystem::path &name, std::vector<
 }
 
 TEST_CASE("TestLight") {
-    LoadTestmap("q2_lightmap_custom_scale.map", {"-threads", "1", "-world_units_per_luxel", "8"});
+    LoadTestmap("q2_lightmap_custom_scale.map", {"-threads", "1", "-world_units_per_luxel", "8", "-novanilla"});
 }
 
 TEST_CASE("emissive cube artifacts") {
@@ -80,7 +80,7 @@ TEST_CASE("emissive cube artifacts") {
     //
     //     "_surflight_rescale" "0"
     //
-    auto [bsp, bspx] = LoadTestmap("light_q2_emissive_cube.map", {"-threads", "1", "-world_units_per_luxel", "4"});
+    auto [bsp, bspx] = LoadTestmap("light_q2_emissive_cube.map", {"-threads", "1", "-world_units_per_luxel", "4", "-novanilla"});
 
     const auto start = qvec3d{1044, -1244, 880};
     const auto end = qvec3d{1044, -1272, 880};
@@ -107,3 +107,43 @@ TEST_CASE("emissive cube artifacts") {
         previous_sample = sample;
     }
 }
+
+TEST_CASE("-novanilla + -world_units_per_luxel")
+{
+    auto [bsp, bspx] = LoadTestmap("q2_lightmap_custom_scale.map", {"-novanilla", "-world_units_per_luxel", "8"});
+
+    for (auto &face : bsp.dfaces) {
+        CHECK(face.lightofs == -1);
+    }
+
+    // make sure no other bspx lumps are written
+    CHECK(bspx.size() == 1);
+    CHECK(bspx.find("DECOUPLED_LM") != bspx.end());
+
+    // make sure all dlightdata bytes are accounted for by the DECOUPLED_LM lump
+    // and no extra was written.
+    size_t expected_dlightdata_bytes = 0;
+    for (auto &face : bsp.dfaces) {
+        // count used styles
+        size_t face_used_styles = 0;
+        for (auto style : face.styles) {
+            if (style != 255) {
+                ++face_used_styles;
+            }
+        }
+
+        // count used pixels per style
+        auto lm_info = BSPX_DecoupledLM(bspx, Face_GetNum(&bsp, &face));
+        const faceextents_t extents(face, bsp, lm_info.lmwidth, lm_info.lmheight, lm_info.world_to_lm_space);
+        int samples_per_face = extents.numsamples() * face_used_styles;
+
+        // round up to multiple of 4
+        if (samples_per_face % 4) {
+            samples_per_face += (4 - (samples_per_face % 4));
+        }
+
+        int bytes_per_face = 3 * samples_per_face;
+        expected_dlightdata_bytes += bytes_per_face;
+    }
+    CHECK(bsp.dlightdata.size() == expected_dlightdata_bytes);
+}