terrain generation | gml

Create a 64 x 64 sprite sprBlock and assign to objBlock, but DO NOT place any blocks into room.

We will generate our terrain programmatically using the room Creation Code:



Default room dimensions of 1024 x 768 means we have a grid of 16x12 blocks: 1024 / 64 = 16, 768 / 64 = 12

This means we have an "arbitrary space" grid of 16 spaces horizontally and 12 spaces vertically to work with:

room0 Creation Code event:

//------------------------ SPECIFICATIONS -----------:
//max / min height (in blocks):
maxHeight = 9;
minHeight = 3;
//to calculate height and width of grid, got to
//spawn an instance of the block first:
temp = instance_create_layer(0,0,"Instances",objBlock); 
blockHeight = objBlock.sprite_height;
blockWidth = objBlock.sprite_width;
gridHeight = room_height / blockHeight;
gridWidth = room_width / blockWidth;
instance_destroy(temp);

//----------------------------------------------------
// TO CREATE TERRAIN:

//1. Set co-ords for our first block:
randomize();
xx = 0;
yy = irandom_range(gridHeight - maxHeight, gridHeight - minHeight);

//2. Moving across the screen...
for(columnToFill = xx; columnToFill <= gridWidth; columnToFill += 1){
	//3. .. work out up one, same height or down one for each column ..
	upSameDown = irandom_range(1,3); //1 up, 2 same height, 3 down
	switch(upSameDown){
	  case 1: if(yy > (gridHeight - maxHeight))yy -= 1; break;
	  case 2: break; //do nothing - same height!
	  case 3: if(yy < (gridHeight - minHeight))yy += 1; break;
	}
		
	//4. .. and fill each column to the ground:
	for(columnPos = yy; columnPos <= gridHeight; columnPos += 1){
	 instance_create_layer(columnToFill * blockWidth, columnPos * blockHeight, "Instances", objBlock);
	}
}