From b96860705d15bf3c4b837a92da43c3ca009e26c1 Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Tue, 28 Sep 2021 22:03:07 -0700
Subject: [PATCH] destruction data for destroy callbacks

---
 src/Silkworm.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/Silkworm.h |  6 ++++
 2 files changed, 89 insertions(+)

diff --git a/src/Silkworm.c b/src/Silkworm.c
index 4098f9e..33dff9c 100644
--- a/src/Silkworm.c
+++ b/src/Silkworm.c
@@ -318,6 +318,15 @@ typedef struct Silkworm_Context
 	uint32_t clothDensity;
 
 	uint8_t* currentBufferAddress; /* GM doesnt let you pass more than 4 arguments with different types lol */
+
+	/* keep track of these so can do callbacks */
+	Silkworm_Vector2* nodeDestructionData;
+	uint32_t nodeDestructionDataCount;
+	uint32_t nodeDestructionDataCapacity;
+
+	Silkworm_Vector2* linkDestructionData;
+	uint32_t linkDestructionDataCount;
+	uint32_t linkDestructionDataCapacity;
 } Silkworm_Context;
 
 static Silkworm_Context *context = NULL;
@@ -353,6 +362,14 @@ void Silkworm_Init()
 	context->xBound = 1000;
 	context->yBound = 1000;
 	context->clothDensity = 4;
+
+	context->nodeDestructionDataCapacity = 16;
+	context->nodeDestructionData = malloc(sizeof(Silkworm_Vector2) * context->nodeDestructionDataCapacity);
+	context->nodeDestructionDataCount = 0;
+
+	context->linkDestructionDataCapacity = 16;
+	context->linkDestructionData = malloc(sizeof(Silkworm_Vector2) * context->nodeDestructionDataCapacity);
+	context->linkDestructionDataCount = 0;
 }
 
 static inline Silkworm_Node* LookupNode(uint64_t nodeId)
@@ -394,6 +411,18 @@ void Silkworm_DestroyNode(double nodeId)
 void Silkworm_Internal_DestroyLink(Silkworm_Link* link)
 {
 	link->markedForDestroy = true;
+
+	if (context->linkDestructionDataCount >= context->linkDestructionDataCapacity)
+	{
+		context->linkDestructionDataCapacity *= 2;
+		context->linkDestructionData = realloc(context->linkDestructionData, sizeof(Silkworm_Vector2) * context->linkDestructionDataCapacity);
+	}
+
+	Silkworm_Vector2 position;
+	position.x = (link->a->position.x + link->b->position.x) / 2;
+	position.y = (link->a->position.y + link->b->position.y) / 2;
+	context->linkDestructionData[context->linkDestructionDataCount] = position;
+	context->linkDestructionDataCount += 1;
 }
 
 void Silkworm_DestroyLink(double linkId)
@@ -580,6 +609,9 @@ void Silkworm_Update(double deltaTime)
 	Silkworm_Link *link;
 	Silkworm_Node *node;
 
+	context->nodeDestructionDataCount = 0;
+	context->linkDestructionDataCount = 0;
+
 	float delta = (float)deltaTime;
 
 	for (i = 0; i < CONSTRAINT_ITERATION_COUNT; i += 1)
@@ -1449,6 +1481,16 @@ void Silkworm_DestroyNodesInRadius(double x, double y, double radius)
 			if (squareDistance <= radius * radius)
 			{
 				Silkworm_DestroyNode(i);
+
+				if (context->nodeDestructionDataCount >= context->nodeDestructionDataCapacity)
+				{
+					context->nodeDestructionDataCapacity *= 2;
+					context->nodeDestructionData = realloc(context->nodeDestructionData, sizeof(Silkworm_Vector2) * context->nodeDestructionDataCapacity);
+
+				}
+
+				context->nodeDestructionData[context->nodeDestructionDataCount] = node->position;
+				context->nodeDestructionDataCount += 1;
 			}
 		}
 	}
@@ -1505,6 +1547,44 @@ double Silkworm_DestroyClothInRadius(double x, double y, double radius)
 	return clothId;
 }
 
+double Silkworm_NodeDestructionDataBufferRequiredSize()
+{
+	return context->nodeDestructionDataCount * (double)sizeof(Silkworm_Vector2);
+}
+
+double Silkworm_FillNodeDestructionDataBuffer()
+{
+	uint32_t i;
+	uint8_t* bufferAddress = context->currentBufferAddress;
+	
+	for (i = 0; i < context->nodeDestructionDataCount; i += 1)
+	{
+		memcpy(bufferAddress, &context->nodeDestructionData[i], sizeof(Silkworm_Vector2));
+		bufferAddress += sizeof(Silkworm_Vector2);
+	}
+
+	return (double)i;
+}
+
+double Silkworm_LinkDestructionDataBufferRequiredSize()
+{
+	return context->linkDestructionDataCount * (double)sizeof(Silkworm_Vector2);
+}
+
+double Silkworm_FillLinkDestructionDataBuffer()
+{
+	uint32_t i;
+	uint8_t* bufferAddress = context->currentBufferAddress;
+
+	for (i = 0; i < context->linkDestructionDataCount; i += 1)
+	{
+		memcpy(bufferAddress, &context->linkDestructionData[i], sizeof(Silkworm_Vector2));
+		bufferAddress += sizeof(Silkworm_Vector2);
+	}
+
+	return (double)i;
+}
+
 void Silkworm_ClearAll()
 {
 	uint32_t i;
@@ -1532,6 +1612,9 @@ void Silkworm_Finish()
 	free(context->linkIndexStack);
 	free(context->clothIndexStack);
 
+	free(context->nodeDestructionData);
+	free(context->linkDestructionData);
+
 	free(context);
 	context = NULL;
 }
\ No newline at end of file
diff --git a/src/Silkworm.h b/src/Silkworm.h
index 067a5f3..19d9414 100644
--- a/src/Silkworm.h
+++ b/src/Silkworm.h
@@ -90,6 +90,12 @@ SILKWORMAPI void Silkworm_PushNodesInRadius(double x, double y, double radius, d
 SILKWORMAPI void Silkworm_DestroyNodesInRadius(double x, double y, double radius);
 SILKWORMAPI double Silkworm_DestroyClothInRadius(double x, double y, double radius);
 
+SILKWORMAPI double Silkworm_NodeDestructionDataBufferRequiredSize();
+SILKWORMAPI double Silkworm_FillNodeDestructionDataBuffer();
+
+SILKWORMAPI double Silkworm_LinkDestructionDataBufferRequiredSize();
+SILKWORMAPI double Silkworm_FillLinkDestructionDataBuffer();
+
 SILKWORMAPI void Silkworm_ClearAll();
 SILKWORMAPI void Silkworm_Finish();