fix: single push constant range (0-160, Vertex|Fragment) — fixes validation errors

- Vulkan spec: each stage can only appear in ONE push constant range
- Merged 3 ranges into 1: offset=0, size=160, stageFlags=Vertex|Fragment
- Both main and shadow pipelines use same single range
- Push constants packed into 160-byte buffer and sent in one call
- Shadow pass: restored vertex/index buffer binding + push constants
- Fixes: device lost, validation errors, missing shadow geometry

src/Engine.Graphics.Vulkan/VulkanPipeline.cs

@@ -150,24 +150,11 @@ internal sealed unsafe class VulkanPipeline : IDisposable
                 pDynamicStates = dynamicStates,
             };
 
-            var pushConstantRanges = stackalloc VkPushConstantRange[3];
-            pushConstantRanges[0] = new VkPushConstantRange
-            {
-                stageFlags = VkShaderStageFlags.Vertex,
-                offset = 0,
-                size = 64,
-            };
-            pushConstantRanges[1] = new VkPushConstantRange
-            {
-                stageFlags = VkShaderStageFlags.Fragment,
-                offset = 64,
-                size = 32,
-            };
-            pushConstantRanges[2] = new VkPushConstantRange
+            var pushConstantRange = new VkPushConstantRange
             {
                 stageFlags = VkShaderStageFlags.Vertex | VkShaderStageFlags.Fragment,
-                offset = 96,
-                size = 64,
+                offset = 0,
+                size = 160,
             };
 
             var descLayout = DescriptorSetLayout;
@@ -176,8 +163,8 @@ internal sealed unsafe class VulkanPipeline : IDisposable
                 sType = VkStructureType.PipelineLayoutCreateInfo,
                 setLayoutCount = 1,
                 pSetLayouts = &descLayout,
-                pushConstantRangeCount = 3,
-                pPushConstantRanges = (nint)pushConstantRanges,
+                pushConstantRangeCount = 1,
+                pPushConstantRanges = (nint)(&pushConstantRange),
             };
 
             fixed (VkPipelineLayout* layoutPtr = &PipelineLayout)

src/Engine.Graphics.Vulkan/VulkanRenderer.cs

@@ -235,6 +235,22 @@ internal sealed unsafe class VulkanRenderer : IRenderer, Engine.Graphics.IScreen
             if (!dc.castShadow) continue;
 
             var vertexBuf = dc.vertexBuf;
+            ulong offset = 0;
+            Vk.vkCmdBindVertexBuffers(cmd, 0, 1, &vertexBuf, &offset);
+            Vk.vkCmdBindIndexBuffer(cmd, dc.indexBuf, 0, 1);
+
+            // Pack all push constants for shadow pass
+            var pcData = stackalloc byte[160];
+            var modelCopy = dc.model;
+            System.Buffer.MemoryCopy(&modelCopy, pcData, 64, 64);
+            var lpCopy = lightPos;
+            System.Buffer.MemoryCopy(&lpCopy, pcData + 64, 16, 16);
+            var lcCopy = lightColor;
+            System.Buffer.MemoryCopy(&lcCopy, pcData + 80, 16, 16);
+            var lvpCopy = lightViewProj;
+            System.Buffer.MemoryCopy(&lvpCopy, pcData + 96, 64, 64);
+
+            Vk.vkCmdPushConstants(cmd, _shadowMap.PipelineLayout, VkShaderStageFlags.Vertex | VkShaderStageFlags.Fragment, 0, 160, pcData);
 
             Vk.vkCmdDrawIndexed(cmd, dc.indexCount, 1, 0, 0, 0);
         }
@@ -332,18 +348,18 @@ internal sealed unsafe class VulkanRenderer : IRenderer, Engine.Graphics.IScreen
             Vk.vkCmdBindVertexBuffers(cmd, 0, 1, &vertexBuf, &offset);
             Vk.vkCmdBindIndexBuffer(cmd, dc.indexBuf, 0, 1);
 
-            var model = dc.model;
-            Vk.vkCmdPushConstants(cmd, _pipeline.PipelineLayout, VkShaderStageFlags.Vertex, 0, 64, &model);
-
-            // Light data as push constants at offset 64 (fragment stage)
+            // Pack all push constants: model(64) + lightPos(16) + lightColor(16) + lightViewProj(64) = 160
+            var pcData = stackalloc byte[160];
+            var modelCopy = dc.model;
+            System.Buffer.MemoryCopy(&modelCopy, pcData, 64, 64);
             var lpCopy = lightPos;
-            Vk.vkCmdPushConstants(cmd, _pipeline.PipelineLayout, VkShaderStageFlags.Fragment, 64, 16, &lpCopy);
+            System.Buffer.MemoryCopy(&lpCopy, pcData + 64, 16, 16);
             var lcCopy = lightColor;
-            Vk.vkCmdPushConstants(cmd, _pipeline.PipelineLayout, VkShaderStageFlags.Fragment, 80, 16, &lcCopy);
-
-            // Light view-proj at offset 96 (vertex + fragment)
+            System.Buffer.MemoryCopy(&lcCopy, pcData + 80, 16, 16);
             var lvpCopy = lightViewProj;
-            Vk.vkCmdPushConstants(cmd, _pipeline.PipelineLayout, VkShaderStageFlags.Vertex | VkShaderStageFlags.Fragment, 96, 64, &lvpCopy);
+            System.Buffer.MemoryCopy(&lvpCopy, pcData + 96, 64, 64);
+
+            Vk.vkCmdPushConstants(cmd, _pipeline.PipelineLayout, VkShaderStageFlags.Vertex | VkShaderStageFlags.Fragment, 0, 160, pcData);
 
             Vk.vkCmdDrawIndexed(cmd, dc.indexCount, 1, 0, 0, 0);
         }

src/Engine.Graphics.Vulkan/VulkanShadowMap.cs

@@ -205,16 +205,14 @@ internal sealed unsafe class VulkanShadowMap : IDisposable
                 pDynamicStates = dynamicStates,
             };
 
-            var pushConstantRanges = stackalloc VkPushConstantRange[2];
-            pushConstantRanges[0] = new VkPushConstantRange { stageFlags = VkShaderStageFlags.Vertex, offset = 0, size = 64 };
-            pushConstantRanges[1] = new VkPushConstantRange { stageFlags = VkShaderStageFlags.Fragment, offset = 64, size = 96 };
+            var pushConstantRange = new VkPushConstantRange { stageFlags = VkShaderStageFlags.Vertex | VkShaderStageFlags.Fragment, offset = 0, size = 160 };
 
             var layoutInfo = new VkPipelineLayoutCreateInfo
             {
                 sType = VkStructureType.PipelineLayoutCreateInfo,
                 setLayoutCount = 0,
-                pushConstantRangeCount = 2,
-                pPushConstantRanges = (nint)pushConstantRanges,
+                pushConstantRangeCount = 1,
+                pPushConstantRanges = (nint)(&pushConstantRange),
             };
 
             var pl = VkPipelineLayout.Null;