From 5b4847d15c390df9e05b52ab8ad8150f539db905 Mon Sep 17 00:00:00 2001
From: Aaron Mueller <mail@aaron-mueller.de>
Date: Mon, 14 Dec 2009 00:28:06 +0100
Subject: [PATCH] Add dynamic generated terrain

---
 src/config.c |  1 +
 src/config.h |  2 +-
 src/draw.c   | 40 ++++++++++++++++++++++++++--------------
 src/draw.h   | 12 ++++++++++--
 src/main.c   |  6 ++++++
 5 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/src/config.c b/src/config.c
index e4f8716..f49bae8 100644
--- a/src/config.c
+++ b/src/config.c
@@ -7,4 +7,5 @@
 SDL_Surface *screen = NULL;
 SDL_Event event;
 bool gameRunning = true;
+int *terrain = NULL;
 
diff --git a/src/config.h b/src/config.h
index 70b2c70..9cb6ffc 100644
--- a/src/config.h
+++ b/src/config.h
@@ -9,7 +9,7 @@
 extern SDL_Surface *screen; // Screen to paint on
 extern SDL_Event event; // Event storage
 extern bool gameRunning; // Set this variable to false to shutdown the game
-
+extern int *terrain; // Game terrain
 
 // Constants
 
diff --git a/src/draw.c b/src/draw.c
index a426d83..e449574 100644
--- a/src/draw.c
+++ b/src/draw.c
@@ -17,6 +17,10 @@ int _sign(float a) {
   return a > 0 ? 1 : (a < 0 ? -1 : 0);
 }
 
+float _random(float from, float to) {
+  return ((to-from)*((float)rand()/RAND_MAX))+from;
+}
+
 void drawLine(int x1, int y1, int x2, int y2, int color) {
   float u, s, v, d1x, d1y, d2x, d2y, m, n;
   int x = x1, y = y1;
@@ -73,22 +77,30 @@ void drawRect(int x1, int y1, int x2, int y2, int color, bool filled) {
 void drawCircle(int x, int y, int radius, int color, bool filled) {
 }
 
-void drawScreen() {
-  Uint32 white = SDL_MapRGB(screen->format, 255, 255, 255);
-  drawPixel(SCREEN_WIDTH/2, SCREEN_HEIGHT/2, white);
-  for (int i=0; i<250; i+=1)
-    drawLine(200, 300-i, 600, 300+i, SDL_MapRGB(screen->format, 0, 0, i));
+int* generateTerrain(float peakheight, float flatness) {
+  time_t start; srand(start);
 
-  drawRect(0, 50, 200, 300, white, true);
-  drawRect(600, 300, 799, 550, white, false);
+  float offset = (float)SCREEN_HEIGHT/2;
+  float r1 = _random(1.0, 5.0);
+  float r2 = _random(1.0, 5.0);
+  float r3 = _random(1.0, 5.0);
+  int *yvals = (int*)malloc(SCREEN_WIDTH*sizeof(int));
+  printf("r1=%f, r2=%f, r3=%f\n", r1, r2, r3);
 
-  // Random dots
-  for (int i=0; i<100; i++)
-    drawPixel(rand()%200+600, rand()%250+300, white);
+  for (int x=0; x<SCREEN_WIDTH; x++) {
+    float y;
+    y  = peakheight/r1*sin((x/flatness*r1)+r1);
+    y += peakheight/r2*sin((x/flatness*r2)+r2);
+    y += peakheight/r3*sin((x/flatness*r3)+r3);
+    y += offset;
+    yvals[x] = (int)y;
+  }
 
-  drawCircle(SCREEN_WIDTH/2, SCREEN_HEIGHT/2, 100, white, true);
-  drawCircle(SCREEN_WIDTH/2, SCREEN_HEIGHT/2, 104, white, false);
-
-  for (int i=0; i<=600; i++) drawLine(0, i, 799, i, white);
+  return &(yvals[0]);
+}
+
+void drawScreen() {
+  Uint32 white = SDL_MapRGB(screen->format, 255, 255, 255);
+  for (int x=0; x<SCREEN_WIDTH; x++) drawLine(x, terrain[x], x, SCREEN_HEIGHT, white);
 }
 
diff --git a/src/draw.h b/src/draw.h
index afffa65..1f2ce60 100644
--- a/src/draw.h
+++ b/src/draw.h
@@ -2,13 +2,21 @@
 #ifndef DRAW_H
 #define DRAW_H
 
-/*
- * Draw a single pixel on the surface with the given color. This is the basic
+/* Draw a single pixel on the surface with the given color. This is the basic
  * function to paint on the screen. We will be use this function for all paint
  * stuff.
  */
 void drawPixel(int x, int y, int color);
 
+/* Some basic shapes
+ */
+void drawLine(int x1, int y1, int x2, int y2, int color);
+void drawRect(int x1, int y1, int x2, int y2, int color, bool filled);
+void drawCircle(int x, int y, int radius, int color, bool filled);
+
+
+int* generateTerrain(float peakheight, float flatness);
+ 
 /*
  * This function will be called for every frame. Here you can actual draw things
  * on the screen.
diff --git a/src/main.c b/src/main.c
index 918535a..1a2ebfa 100644
--- a/src/main.c
+++ b/src/main.c
@@ -10,6 +10,9 @@ int main(int argc, char **argv) {
   SDL_Init(SDL_INIT_VIDEO);
   screen = SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, 32, SDL_HWSURFACE | SDL_DOUBLEBUF);
 
+  // Initialize internal game state
+  terrain = generateTerrain(150.0, 180.0);
+  
   // the main game loop
   while (gameRunning == true) {
     // Check for events
@@ -24,6 +27,9 @@ int main(int argc, char **argv) {
     SDL_Flip(screen);
   }
 
+  // Cleanup and quit
+  free(terrain);
+
   SDL_Quit();
   return 0;
 }