perf(terrain): Hoist global light ray computation out of per-vertex loop

Author: Cellcote

Core/GameEngineDevice/Include/W3DDevice/GameClient/BaseHeightMap.h

@@ -157,7 +157,7 @@ class BaseHeightMapRenderObjClass : public RenderObjClass, public DX8_CleanupHoo
 	void updateMacroTexture(AsciiString textureName);
 	void doTextures(Bool flag) {m_disableTextures = !flag;};
 	/// Update the diffuse value from static light info for one vertex.
-	void doTheLight(VERTEX_FORMAT *vb, Vector3*light, Vector3*normal, RefRenderObjListIterator *pLightsIterator, UnsignedByte alpha);
+	void doTheLight(VERTEX_FORMAT *vb, const Vector3*light, Vector3*normal, RefRenderObjListIterator *pLightsIterator, UnsignedByte alpha);
 	void addScorch(Vector3 location, Real radius, Scorches type);
 	void addTree(DrawableID id, Coord3D location, Real scale, Real angle,
 								Real randomScaleAmount,  const W3DTreeDrawModuleData *data);

Core/GameEngineDevice/Source/W3DDevice/GameClient/BaseHeightMap.cpp

@@ -504,7 +504,7 @@ static lights into account as well.  It is possible to just use the normal in th
 vertex and let D3D do the lighting, but it is slower to render, and can only
 handle 4 lights at this point. */
 //=============================================================================
-void BaseHeightMapRenderObjClass::doTheLight(VERTEX_FORMAT *vb, Vector3*light, Vector3*normal, RefRenderObjListIterator *pLightsIterator, UnsignedByte alpha)
+void BaseHeightMapRenderObjClass::doTheLight(VERTEX_FORMAT *vb, const Vector3*light, Vector3*normal, RefRenderObjListIterator *pLightsIterator, UnsignedByte alpha)
 {
 #ifdef USE_NORMALS
 	vb->nx = normal->X;

Core/GameEngineDevice/Source/W3DDevice/GameClient/HeightMap.cpp

@@ -306,7 +306,6 @@ Int HeightMapRenderObjClass::updateVB(DX8VertexBufferClass	*pVB, VERTEX_FORMAT *
 {
 	Int i,j;
 	Vector3 lightRay[MAX_GLOBAL_LIGHTS];
-	const Coord3D *lightPos;
 	Int xCoord, yCoord;
 	Int vn0,un0,vp1,up1;
 	Vector3 l2r,n2f,normalAtTexel;
@@ -320,6 +319,12 @@ Int HeightMapRenderObjClass::updateVB(DX8VertexBufferClass	*pVB, VERTEX_FORMAT *
 		assert(x0 >= originX && y0 >= originY && x1>x0 && y1>y0 && x1<=originX+VERTEX_BUFFER_TILE_LENGTH && y1<=originY+VERTEX_BUFFER_TILE_LENGTH);
 #endif
 
+		for (Int lightIndex=0; lightIndex < TheGlobalData->m_numGlobalLights; lightIndex++)
+		{
+			const Coord3D& lightPos = TheGlobalData->m_terrainLightPos[lightIndex];
+			lightRay[lightIndex].Set(-lightPos.x, -lightPos.y, -lightPos.z);
+		}
+
 		DX8VertexBufferClass::WriteLockClass lockVtxBuffer(pVB);
 		VERTEX_FORMAT *vbHardware = (VERTEX_FORMAT*)lockVtxBuffer.Get_Vertex_Array();
 		VERTEX_FORMAT *vBase = data;
@@ -362,12 +367,6 @@ Int HeightMapRenderObjClass::updateVB(DX8VertexBufferClass	*pVB, VERTEX_FORMAT *
 				pMap->getUVData(mapX, mapY, U, V);
 				pMap->getAlphaUVData(mapX, mapY, UA, VA, alpha, &flipForBlend);
 
-				for (Int lightIndex=0; lightIndex < TheGlobalData->m_numGlobalLights; lightIndex++)
-				{
-					lightPos=&TheGlobalData->m_terrainLightPos[lightIndex];
-					lightRay[lightIndex].Set(-lightPos->x,-lightPos->y,	-lightPos->z);
-				}
-
 				//top-left sample
 				l2r.Set(2*MAP_XY_FACTOR,0,MAP_HEIGHT_SCALE*(pMap->getDisplayHeight(mapX+cellOffset, mapY) - pMap->getDisplayHeight(un0, mapY)));
 				n2f.Set(0,2*MAP_XY_FACTOR,MAP_HEIGHT_SCALE*(pMap->getDisplayHeight(mapX, (mapY+cellOffset)) - pMap->getDisplayHeight(mapX, vn0)));