# HG changeset patch
# User sam <sam@basx.dev>
# Date 1737471611 -25200
# Node ID e54ef155de10051e71f1be2134586ea105a24a1b
# Parent  cf0bae787044d0c84ea9a9b77eb490441034ea11
add: check whether submitted vertex-attribute-arrays have all the same length

diff -r cf0bae787044 -r e54ef155de10 semicongine/rendering/renderer.nim
--- a/semicongine/rendering/renderer.nim	Mon Jan 20 23:12:30 2025 +0700
+++ b/semicongine/rendering/renderer.nim	Tue Jan 21 22:00:11 2025 +0700
@@ -1,4 +1,5 @@
 import std/typetraits
+import std/strformat
 import std/macros
 import std/logging
 
@@ -284,16 +285,30 @@
       for meshName, meshValue in mesh.fieldPairs:
         when meshName == shaderAttributeName:
           debug("  vertex attr: ", shaderAttributeName)
+          assert meshValue.buffer.vk.Valid,
+            "Mesh vertex-attribute '{TMesh}.{shaderAttributeName}' has no valid buffer (encountered while rendering with '{TShader}')"
           vertexBuffers.add meshValue.buffer.vk
           vertexBuffersOffsets.add meshValue.offset
-          elementCount = meshValue.data.len.uint32
+          if elementCount == 0:
+            elementCount = meshValue.data.len.uint32
+          else:
+            assert meshValue.data.len.uint32 == elementCount,
+              "Mesh attribute '" & $(TMesh) & "." & meshName & "' has length " &
+                $(meshValue.data.len) & " but previous attributes had length " &
+                $elementCount
     elif hasCustomPragma(shaderAttribute, InstanceAttribute):
       for instanceName, instanceValue in instances.fieldPairs:
         when instanceName == shaderAttributeName:
           debug("  instnc attr: ", shaderAttributeName)
           vertexBuffers.add instanceValue.buffer.vk
           vertexBuffersOffsets.add instanceValue.offset
-          instanceCount = instanceValue.data.len.uint32
+          if instanceCount == 1:
+            instanceCount = meshValue.data.len.uint32
+          else:
+            assert instanceValue.data.len.uint32 == instanceCount,
+            "Mesh instance attribute '" & $(TMesh) & "." & instanceName & "' has length " &
+              $(instanceValue.data.len) & " but previous attributes had length " &
+              $instanceCount
 
   if vertexBuffers.len > 0:
     vkCmdBindVertexBuffers(