From 75098a16e5891973bfe458388ceef33f9dff9423 Mon Sep 17 00:00:00 2001
From: Luke Bratch <l_bratch@yahoo.co.uk>
Date: Sat, 27 Nov 2010 23:00:36 +0000
Subject: Level: Implement collision detection

---
 Level.cpp | 61 ++++++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 15 deletions(-)

(limited to 'Level.cpp')

diff --git a/Level.cpp b/Level.cpp
index 0cecd50..848c9c4 100644
--- a/Level.cpp
+++ b/Level.cpp
@@ -45,33 +45,51 @@ void Level::changeLevel(int levelNo) {
 }
 
 void Level::move() {
-    int newX, newY;
+    // Construct a rectangle for player, for collision detection
+    SDL_Rect rect;
+    rect.w = player.getClip()->w;
+    rect.h = player.getClip()->h;
+    // Only record y-coord for now
+    rect.y = player.getY();
 
     // Apply gravity
     player.incYVel(GRAVITY);
 
     // Player x-axis movement
-    newX = player.getX() + player.getXVel();
-    // Don't let player go off either end of the screen
-    if (newX >= 0 && newX <= SCREEN_WIDTH - MARCUS_WIDTH) {
-        player.setX(newX);
+    rect.x = player.getX() + player.getXVel();
+
+    // If there's a collision in the x-axis ...
+    while (checkCollision(rect)) {
+        // ... fit snugly to edge
+        if (player.getXVel() > 0) {
+            rect.x--;
+        } else {
+            rect.x++;
+        }
+    }
+
+    if (rect.x >= 0 && rect.x <= SCREEN_WIDTH - rect.w) {
+        player.setX(rect.x);
     }
 
     // Player y-axis movement
-    newY = player.getY() + player.getYVel();
-    // Don't let player fall below bottom of screen
-    if (newY <= SCREEN_HEIGHT - MARCUS_HEIGHT) {
-        player.setY(newY);
-    } else {
-        // If player was going to fall off, fit snugly to edge
-        while (newY > SCREEN_HEIGHT - MARCUS_HEIGHT) {
-            newY--;
+    rect.y = player.getY() + player.getYVel();
+
+    // If there's a collision in the y-axis ...
+    if (checkCollision(rect)) {
+        while (checkCollision(rect)) {
+            // ... fit snugly to edge
+            if (player.getYVel() > 0)
+                rect.y--;
+            else
+                rect.y++;
         }
-        player.setY(newY);
-        // Reset velocity
+
         player.setYVel(0);
     }
 
+    player.setY(rect.y);
+
     player.orient();
 }
 
@@ -138,4 +156,17 @@ void Level::loadMap(int LevelNo) {
 
     // Close map file
     map.close();
+}
+
+bool Level::checkCollision(SDL_Rect r) {
+    // Loop through each platform
+    for (int i = 0; i < numPlatforms; i++) {
+        // Check for collisions in the x-axis ...
+        if (r.x - cameraX > platform[i].getX() - r.w && r.x - cameraX < platform[i].getX() + TILE_SIZE)
+            // ... if found, check for collisions in the y-axis
+            if (r.y > platform[i].getY() - r.h && r.y < platform[i].getY() + TILE_SIZE)
+                return true;
+    }
+
+    return false;
 }
\ No newline at end of file
-- 
cgit v1.2.3