I finally got my lighting algorithm working correctly, but it doesn't seem to be the fastest.. I put 5 lights on my map and my framerate dropped to about 28fps... Normally it gets about 75-80 fps or so.. (BTW, this is a 2D app, not a 3D app, but I'm using D3D vertex lighting to draw it) Here's the fragment of code that does the light calculation. // Process Light Sources. EntityList = FirstEntity; while (EntityList != NULL) { // Loop through entities, if they emit light, process them into light map. if ((EntityList->Entity->LightIntensity > 0) && (EntityList->Entity->LightRadius > 0)) { Entity = EntityList->Entity; for (indexY=0; indexY < LMAP_HEIGHT; indexY++) { for (indexX=0; indexX < LMAP_WIDTH; indexX++) { Dist = sqrt (pow(((Entity->X - OffsetX) - (indexX * 32)), 2) + pow(((Entity->Y - OffsetY) - (indexY * 32)), 2)); // if within light radius, calc it. if (Dist < Entity->LightRadius) { // Calc modifier based on radius and intensity. Color = (float)Entity->LightIntensity / 50; Color = Color * ((float)1.0 - ((float)Dist / Entity->LightRadius)); if (Color < 0) Color = 0; // Do Red Value = LightMap[indexX][indexY].Red + (Color * ((Entity->LightColor.Red * 2) - 255)); if (Value > 255) Value = 255; if (Value < 0) Value = 0; LightMap[indexX][indexY].Red = (unsigned char)Value; // Do Green Value = LightMap[indexX][indexY].Green + (Color * ((Entity->LightColor.Green * 2) - 255)); if (Value > 255) Value = 255; if (Value < 0) Value = 0; LightMap[indexX][indexY].Green = (unsigned char)Value; // Do Blue Value = LightMap[indexX][indexY].Blue + (Color * ((Entity->LightColor.Blue * 2) - 255)); if (Value > 255) Value = 255; if (Value < 0) Value = 0; LightMap[indexX][indexY].Blue = (unsigned char)Value; } } } } EntityList = EntityList->NextEntity; } (heh, caught a few obvious ones myself) If anyone can make any suggestions I'd be appreciative. I myself think the sqrt func is the culprit. Any ways to make it faster? -Zims Edited by - Zimans on 7/23/00 3:09:20 PM Edited by - Zimans on 7/23/00 3:16:39 PM