Initial clone in from local subversion server

demo/gravity/cpp/demo.cpp

@@ -0,0 +1,61 @@
+/*
+ * This demo just creates a ball that moves up, and allows gravity to effect it.
+ * The effect is to cause the velocity of the ball to change, causing it to travel
+ * in a parabola on the Y axis rather than simply going straight up or straight down.
+ */
+
+#include <libgame/libgame.h>
+
+int main(int argc, char *argv[])
+{
+	Display2D display = Display2D();
+	Game &myGame = Game::NewSingleton();
+	Animation *anim = NULL;
+	Actor ball;
+	SpriteStrip *strip = NULL;
+	float gravity = 0.1;
+	unsigned int lastTimer = 0;
+
+	Vector actorPos;
+	Vector actorVel;
+
+	myGame.initSDL();
+	myGame.initVideo(640, 480, 32, SDL_HWSURFACE|SDL_DOUBLEBUF);
+	display.initVideo((Vector){0,0,0}, 640, 480, 32, SDL_HWSURFACE);
+	display.setActive(1);
+	myGame.windows.push_back(&display);
+
+	strip = myGame.newSpriteStrip("ball");
+	strip->loadFromFile("ball.png", 32, 32, (Vector){0,0,0});
+	anim = myGame.newAnimation("ball");
+	anim->setStrip(strip, 0, 0, (Vector){0,0,0});
+	ball.addAnimation(anim, STATE_DEFAULT);
+	ball.setState(STATE_MOVERIGHT | STATE_MOVEUP);
+	ball.setPosition((Vector){0,400,0});
+	ball.setVelocity((Vector){1, 1.5, 0});
+
+	display.addActor(&ball, LAYER_SPRITE1);
+
+	lastTimer = SDL_GetTicks();
+
+	while ( 1 ) {
+	    actorPos = ball.getPosition();
+	    if ( actorPos.y >= 480 ) {
+		break;
+	    }
+	    if ( (SDL_GetTicks() - lastTimer) >= (1000/30) ) {
+		myGame.update();
+		actorVel = ball.getVelocity();
+		actorVel.y -= gravity;
+		ball.setVelocity(actorVel);
+		lastTimer = SDL_GetTicks();
+	    } else {
+		myGame.update(1);
+	    }
+	    if ( myGame.keyHeldDown(SDLK_ESCAPE) ) {
+		break;
+	    }
+	    myGame.finishFrame();
+	}
+	return 0;
+}