feat: draw meshes with instanced multi-draw indirect

destrum/assets_src/shaders/shadow.vert

@@ -4,17 +4,18 @@
 #extension GL_EXT_buffer_reference : require
 #extension GL_EXT_scalar_block_layout : require
 
-#include "vertex.glsl"
+#include "instance_data.glsl"
 
 layout (push_constant, scalar) uniform constants
 {
-    mat4 modelToLightClip;
-    VertexBuffer vertexBuffer;
+    mat4 lightViewProj;
+    InstanceBuffer instanceBuffer;
 } pcs;
 
 void main()
 {
-    Vertex v = pcs.vertexBuffer.vertices[gl_VertexIndex];
+    InstanceData instance = pcs.instanceBuffer.instances[gl_InstanceIndex];
+    Vertex v = instance.vertexBuffer.vertices[gl_VertexIndex];
 
-    gl_Position = pcs.modelToLightClip * vec4(v.position, 1.0f);
+    gl_Position = pcs.lightViewProj * instance.transform * vec4(v.position, 1.0f);
 }