Implemented zoom in/out with the scroll wheel

The focus of the zooming is the top left of the screen, but that is fine
for now.

src/base_scene.cpp

@@ -86,6 +86,10 @@ void BaseScene::ProcessEvents() {
 				MouseButtonUp(event.button);
 			break;
 
+			case SDL_MOUSEWHEEL:
+				MouseWheel(event.wheel);
+			break;
+
 			case SDL_KEYDOWN:
 				KeyDown(event.key);
 			break;

src/example_scene.cpp

@@ -65,6 +65,7 @@ void ExampleScene::FrameEnd() {
 
 void ExampleScene::RenderFrame(SDL_Renderer* renderer) {
 	for (std::list<Region>::iterator it = regionPager.GetContainer()->begin(); it != regionPager.GetContainer()->end(); it++) {
+		//NOTE: Graphical scaling is done internally
 		tileSheet.DrawRegionTo(renderer, &(*it), camera.x, camera.y, camera.scale, camera.scale);
 	}
 }
@@ -76,8 +77,8 @@ void ExampleScene::RenderFrame(SDL_Renderer* renderer) {
 void ExampleScene::MouseMotion(SDL_MouseMotionEvent const& event) {
 	//right mouse button moves the camera
 	if (event.state & SDL_BUTTON_RMASK) {
-		camera.x -= event.xrel;
-		camera.y -= event.yrel;
+		camera.x -= event.xrel / camera.scale;
+		camera.y -= event.yrel / camera.scale;
 	}
 }
 
@@ -85,14 +86,15 @@ void ExampleScene::MouseButtonDown(SDL_MouseButtonEvent const& event) {
 	switch(event.button) {
 		case SDL_BUTTON_LEFT: {
 			//DOCS: broke this down into several lines for clarity
-			//these are the "real" click positions, relative to the map (can be scaled)
-			int fieldX = event.x + camera.x;
-			int fieldY = event.y + camera.y;
+			//these are the "real" click positions, relative to the map
+			//(scaled input is transformed into unscaled tile selection)
+			int fieldX = event.x / camera.scale + camera.x;
+			int fieldY = event.y / camera.scale + camera.y;
 
 			//these are the x & y indexes of the selected tile
 			//NOTE: the terniary operator is used to circumvent an error with integer devision
-			int tileX = (fieldX >= 0 ? fieldX : fieldX - 32) / 32;
-			int tileY = (fieldY >= 0 ? fieldY : fieldY - 32) / 32;
+			int tileX = (fieldX >= 0 ? fieldX : fieldX - tileSheet.GetTileW()) / tileSheet.GetTileW();
+			int tileY = (fieldY >= 0 ? fieldY : fieldY - tileSheet.GetTileH()) / tileSheet.GetTileH();
 
 			//finally, call the method
 			regionPager.SetTile(tileX, tileY, layer, selection);
@@ -106,7 +108,29 @@ void ExampleScene::MouseButtonUp(SDL_MouseButtonEvent const& event) {
 }
 
 void ExampleScene::MouseWheel(SDL_MouseWheelEvent const& event) {
-	//
+	constexpr double scaleMod = 1.2;
+	constexpr double scaleUpperBound = 3.0;
+	constexpr double scaleLowerBound = 0.5;
+
+	//zoom out
+	if (event.y < 0) { //downscroll
+		if (camera.scale / scaleMod <= scaleLowerBound) {
+			camera.scale = scaleLowerBound;
+		}
+		else {
+			camera.scale /= scaleMod;
+		}
+	}
+
+	//zoom in
+	if (event.y > 0) { //upscroll
+		if (camera.scale * scaleMod >= scaleUpperBound) {
+			camera.scale = scaleUpperBound;
+		}
+		else {
+			camera.scale *= scaleMod;
+		}
+	}
 }
 
 void ExampleScene::KeyDown(SDL_KeyboardEvent const& event) {

src/libmap/region.hpp

@@ -52,6 +52,8 @@ public:
 
 	std::bitset<REGION_WIDTH*REGION_HEIGHT>* GetSolidBitset();
 private:
+	friend class TileSheet;
+
 	const int x;
 	const int y;
 

src/libmap/tile_sheet.cpp

@@ -21,6 +21,8 @@
 */
 #include "tile_sheet.hpp"
 
+#include <stdexcept>
+
 TileSheet& TileSheet::operator=(TileSheet const& rhs) {
 	//don't screw yourself
 	if (this == &rhs) {
@@ -85,21 +87,37 @@ void TileSheet::DrawLayerTo(SDL_Renderer* const renderer, Region* const region,
 }
 
 void TileSheet::DrawRegionTo(SDL_Renderer* const renderer, Region* const region, int camX, int camY, double scaleX, double scaleY) {
-	//TODO: (2) make TileSheet a friend class of Region
+	//NOTE: TileSheet is a friend class of Region
+	//reimplementing DrawTo() to improve performance (less indirection)
+	if (!texture) {
+		throw(std::logic_error("No image texture to draw"));
+	}
+
+	//the local variables
+	SDL_Rect sclip = {0, 0, clip.w, clip.h};
+	SDL_Rect dclip = {0, 0, Uint16(clip.w * scaleX), Uint16(clip.h * scaleY)};
 	Region::type_t tile = 0;
+
+	//for each tile
 	for (register int i = 0; i < REGION_WIDTH; ++i) {
 		for (register int j = 0; j < REGION_HEIGHT; ++j) {
 			for (register int k = 0; k < REGION_DEPTH; ++k) {
-				tile = region->GetTile(i, j, k);
+				//get the value to skip expensive lookups
+				tile = region->tiles[i][j][k];
+
 				//0 is invisible
 				if (tile == 0) continue;
-				clip.x = (tile-1) % countX * clip.h;
-				clip.y = (tile-1) / countX * clip.w;
-				//TODO: (2) raw rendering; improve preformance
-				Image::DrawTo(renderer,
-					(region->GetX() + i) * clip.w - camX,
-					(region->GetY() + j) * clip.h - camY,
-					scaleX, scaleY);
+
+				//set the sclip
+				sclip.x = (tile-1) % countX * clip.h;
+				sclip.x = (tile-1) / countX * clip.w;
+
+				//set the dclip
+				dclip.x = ((region->x + i) * clip.w - camX) * scaleX;
+				dclip.y = ((region->y + j) * clip.h - camY) * scaleY;
+
+				//draw
+				SDL_RenderCopy(renderer, texture, &sclip, &dclip);
 			}
 		}
 	}