fix lightning glow offset and collision LOD clamp (#8012)

Section-start glows used the b_add of the most recently created bolt
type (Nebl_type) rather than the bolt being drawn, so concurrent bolts
of different types got the wrong glow offset.  The cap glow already
used the correct type.

Clamp $Collision LOD to num_detail_levels - 1, the highest valid
detail level.  The previous bound was harmless because the collision
code falls back to the lowest existing LOD, but it was off by one.

Co-authored-by: Claude Opus 5.5 <[email protected]>

code/graphics/vulkan/VulkanPipeline.h

@@ -121,6 +121,12 @@ public:
 	 */
 	vk::Pipeline getPipeline(const PipelineConfig& config, const vertex_layout& vertexLayout);
 
+	/**
+	 * @brief Destroy all cached pipelines; later getPipeline calls build them again
+	 * @note No submitted or recording command buffer may still use them
+	 */
+	void forgetAllPipelines() { m_pipelines.clear(); }
+
 	/**
 	 * @brief Get the common pipeline layout
 	 *

code/graphics/vulkan/VulkanRenderer.h

@@ -95,6 +95,12 @@ class VulkanRenderer {
 	 */
 	void setupFrame();
 
+	/**
+	 * @brief Drop every cached pipeline at the start of the next frame; each is rebuilt on its next use
+	 * Called after the shaders are recompiled, since a pipeline keeps the shader code it was built from
+	 */
+	void requestPipelineRebuild() { m_pipelinesStale = true; }
+
 	/**
 	 * @brief End frame - ends render pass, submits, and presents
 	 * Called at the END of each frame after all draw calls
@@ -533,6 +539,7 @@ class VulkanRenderer {
 	vk::CommandBuffer m_currentCommandBuffer;
 	SCP_vector<vk::CommandBuffer> m_currentCommandBuffers;  // For cleanup
 	bool m_frameInProgress = false;
+	bool m_pipelinesStale = false;
 
 	// Swap chain recreation
 	bool m_swapChainNeedsRecreation = false;

code/graphics/vulkan/VulkanRendererLoop.cpp

@@ -101,6 +101,14 @@ void VulkanRenderer::setupFrame()
 		return;
 	}
 
+	// before recording: the recompile can run mid-frame, while the frame being recorded still holds old pipelines
+	if (m_pipelinesStale) {
+		mprintf(("Vulkan: shaders were recompiled, rebuilding pipelines\n"));
+		m_device->waitIdle();
+		m_pipelineManager->forgetAllPipelines();
+		m_pipelinesStale = false;
+	}
+
 	// Free completed texture upload command buffers
 	Assertion(m_textureManager, "Vulkan TextureManager not initialized in setupFrame!");
 	m_textureManager->frameStart();

code/graphics/vulkan/VulkanShader.cpp

@@ -1,5 +1,7 @@
 #include "VulkanShader.h"
 #include "VulkanShaderCompiler.h"
+#include "VulkanRenderer.h"
+#include "gr_vulkan.h"
 
 namespace graphics::vulkan {
 
@@ -29,6 +31,7 @@ void vulkan_recompile_all_shaders(const std::function<void(size_t, size_t)>& pro
 {
 	auto* shaderManager = getShaderManager();
 	shaderManager->recompileAllShaders(progressCallback);
+	getRendererInstance()->requestPipelineRebuild();
 }
 
 VulkanShaderManager::VulkanShaderManager() = default;
@@ -143,13 +146,19 @@ void VulkanShaderManager::recompileAllShaders(const std::function<void(size_t, s
 				}
 
 				shader.valid = shader.vertexModule && shader.fragmentModule;
+				// the inactive anti-aliasing family cannot compile under the current mode, so build it again on next use
+				if (!shader.valid) {
+					m_shaderMap.erase(shader_key_t(static_cast<int>(type), flags));
+					m_freeSlots.push_back(static_cast<size_t>(&shader - m_shaders.data()));
+				}
 			}
 		}
 
-		++current;
+		// callers expect 0..total-1, like OpenGL; the retail options popup waits for current + 1 == total
 		if (progressCallback) {
 			progressCallback(current, total);
 		}
+		++current;
 	}
 
 	nprintf(("vulkan", "VulkanShaderManager: Recompiled %zu shaders\n", total));

code/nebula/neblightning.cpp

@@ -1116,7 +1116,7 @@ void nebl_generate_section(bolt_type *bi, float width, l_node *a, l_node *b, l_s
 		}
 	}
 	// calculate the glow points		
-	nebl_calc_facing_pts_smart(&glow_a, &glow_b, &dir_normal, &a->pos, pinch_a ? 0.5f : width * 6.0f, Nebl_type->b_add);
+	nebl_calc_facing_pts_smart(&glow_a, &glow_b, &dir_normal, &a->pos, pinch_a ? 0.5f : width * 6.0f, bi->b_add);
 	g3_transfer_vertex(&c->glow_vex[0], &glow_a);
 	g3_transfer_vertex(&c->glow_vex[1], &glow_b);
 

code/ship/ship.cpp

@@ -3041,7 +3041,7 @@ static void parse_ship_values(ship_info* sip, const bool is_template, const bool
 		stuff_int(&sip->collision_lod);
 
 		// Cap to sane values, just in case
-		sip->collision_lod = MAX(0, MIN(sip->collision_lod, sip->num_detail_levels));
+		sip->collision_lod = MAX(0, MIN(sip->collision_lod, sip->num_detail_levels - 1));
 	}
 
 	// check for optional pixel colors