All Episodes in this Season
Episode #099 - Split Screen Many two-player games on Commodore 64 split the screen horizontally and present separate view for each player. Today we are going to do it ourselves. We are going to make two horizontal parts of the screen scroll independently of each other.
Episode #098 - Binary Coded Decimal One of the pretty common tasks we encounter while creating a game is printing the score. It can also be surprisingly difficult. Especially if you need an efficient solution. Today we will learn how an underestimated feature of the 6510 processor - the binary coded decimal mode, can be used to update and print the score efficiently.
Episode #097 - Printing Bin & Hex Numbers II In the previous episode, we've created pseudo commands that converted numbers into their binary and hexadecimal string representations. They will work fine in most cases when we need to either print the string directly to the screen or store them in the memory. But sometimes we might prefer to have print commands that would use the KERNAL's character output routine. This way we wouldn't need to care about the screen coordinates and have the number printed at the current cursor position.
Episode #096 - Printing Bin & Hex Numbers I When programming Commodore 64 we are using different representations of numbers. Sometimes it is more convenient to use a plain old decimal version, especially when we need to use any arithmetic. But when we operate on specific bits of a number it is easier to use a binary representation. Memory addresses, on the other hand, are more natural to read as hexadecimal numbers. In the source code, we can easily change the representation of a number. But we don't have any built-in way of printing them on the screen. Today we will solve this problem.
Episode #095 - Safe Branching Often in programming Commodore 64, we need accurate and compact delay loops. We usually create them using one of branching instructions. Once we introduce such loop, our code can become fragile, since branches can take one cycle more if the jump lands on a different page than the next instruction. And it can happen by accident if we add some code to before those instructions or if we relocate the program. This can lead to frustrating debugging sessions since the compiler doesn't warn us about this problem automatically. Today we will change that.
Episode #094 - Counting Cycles Aren't you tired of counting cycles in your routines by hand? Looking up specifications of every single instruction gets old soon. It's especially hard if your code contains branches and loops. Not to mention page crossing. Wouldn't it be great to have the cycle-count computed automatically? In this tutorial, we are going to create a library. You'll be able to include it in any project. It will automatically compute how many cycles your routine takes. We won't need to look up specifications of every single instruction. We will also make sure the library works well by using Test Driven Development to create it.
Episode #093 - Sprites everywhere Can we display more than 8 sprites on the screen with side borders open? Of course, we can! You'll learn how in less than eight minutes!
Episode #092 - Sprites on the border IV - Four on a bad line In the previous episode, we've found a way to display sprite-zero while also having the side border open. In this video we will figure out if that's possible on a bad line.
Episode #091 - Sprites on the border III - Eight sprites In this episode, we will learn how to display sprite zero while the side border is open. This allows us to draw all eight sprites on the top and the bottom part of the border where there are no bad lines.