One and the same

- Add model id debug view
- Want to be able to visually check that instances are pointing to the
  same model

common/src/backend/java/dev/engine_room/flywheel/backend/engine/instancing/InstancedDraw.java

@@ -42,6 +42,10 @@ public class InstancedDraw {
 		return deleted;
 	}
 
+	public MeshPool.PooledMesh mesh() {
+		return mesh;
+	}
+
 	public void render(TextureBuffer buffer) {
 		if (mesh.isInvalid()) {
 			return;

common/src/backend/java/dev/engine_room/flywheel/backend/engine/instancing/InstancedRenderStage.java

@@ -64,6 +64,9 @@ public class InstancedRenderStage {
 
 				uploadMaterialUniform(program, material);
 
+				program.setUInt("_flw_vertexOffset", drawCall.mesh()
+						.baseVertex());
+
 				MaterialRenderState.setup(material);
 
 				Samplers.INSTANCE_BUFFER.makeActive();

common/src/backend/java/dev/engine_room/flywheel/backend/engine/uniform/DebugMode.java

@@ -14,6 +14,7 @@ public enum DebugMode implements StringRepresentable {
 	LIGHT_COLOR,
 	OVERLAY,
 	DIFFUSE,
+	MODEL_ID,
 	;
 
 	public static final Codec<DebugMode> CODEC = StringRepresentable.fromEnum(DebugMode::values);

common/src/backend/resources/assets/flywheel/flywheel/internal/common.frag

@@ -14,7 +14,7 @@ in vec2 _flw_crumblingTexCoord;
 #endif
 
 #ifdef _FLW_DEBUG
-flat in uint _flw_instanceID;
+flat in uvec2 _flw_ids;
 #endif
 
 out vec4 _flw_outputColor;
@@ -79,7 +79,7 @@ void _flw_main() {
         color = vec4(flw_vertexNormal * .5 + .5, 1.);
         break;
         case 2u:
-        color = _flw_id2Color(_flw_instanceID);
+        color = _flw_id2Color(_flw_ids.x);
         break;
         case 3u:
         color = vec4(vec2((flw_fragLight * 15.0 + 0.5) / 16.), 0., 1.);
@@ -93,6 +93,9 @@ void _flw_main() {
         case 6u:
         color = vec4(vec3(diffuseFactor), 1.);
         break;
+        case 7u:
+        color = _flw_id2Color(_flw_ids.y);
+        break;
     }
     #endif
 

common/src/backend/resources/assets/flywheel/flywheel/internal/common.vert

@@ -72,10 +72,10 @@ mat3 _flw_normalMatrix;
 #endif
 
 #ifdef _FLW_DEBUG
-flat out uint _flw_instanceID;
+flat out uvec2 _flw_ids;
 #endif
 
-void _flw_main(in FlwInstance instance, in uint stableInstanceID) {
+void _flw_main(in FlwInstance instance, in uint stableInstanceID, in uint modelID) {
     _flw_layoutVertex();
     flw_instanceVertex(instance);
     flw_materialVertex();
@@ -96,6 +96,6 @@ void _flw_main(in FlwInstance instance, in uint stableInstanceID) {
     gl_Position = flw_viewProjection * flw_vertexPos;
 
     #ifdef _FLW_DEBUG
-    _flw_instanceID = stableInstanceID;
+    _flw_ids = uvec2(stableInstanceID, modelID);
     #endif
 }

common/src/backend/resources/assets/flywheel/flywheel/internal/indirect/main.vert

@@ -51,5 +51,5 @@ void main() {
 
     FlwInstance instance = _flw_unpackInstance(instanceIndex);
 
-    _flw_main(instance, instanceIndex);
+    _flw_main(instance, instanceIndex, draw.vertexOffset);
 }

common/src/backend/resources/assets/flywheel/flywheel/internal/instancing/main.vert

@@ -10,6 +10,8 @@ uniform mat4 _flw_modelMatrixUniform;
 uniform mat3 _flw_normalMatrixUniform;
 #endif
 
+uniform uint _flw_vertexOffset;
+
 void main() {
     _flw_unpackMaterialProperties(_flw_packedMaterial.y, flw_material);
 
@@ -20,5 +22,5 @@ void main() {
     _flw_normalMatrix = _flw_normalMatrixUniform;
     #endif
 
-    _flw_main(instance, uint(gl_InstanceID));
+    _flw_main(instance, uint(gl_InstanceID), _flw_vertexOffset);
 }