Questions tagged [graphics]

For questions regarding graphical - as opposed to text - processing and display.

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5
votes
1answer
159 views

Why are the CBM control codes for color setting so spread out?

The control codes (my C64 handbook actually calls them ASCII codes) for color changing on the Commodore 64 are as follows: Color Control Code Color number BLACK $90 0 ...
3
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2answers
162 views

Is there a way to blank out a portion of a screen on Commdore C64?

I would like to blank out a couple of lines between two given rasterlines. Above that I'm planning to have a scrolling background and sprites, below that is a textual info area. I'm thinking of a ...
1
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0answers
103 views

Help debugging a circuit/code for Z80 and TMS9918ANL

I am working on designing a Z80 computer that utilized the TMS9918ANL for graphics. I am currently just trying to make sure the TMS9918ANL is working, so I hooked up the control pins the bus (...
2
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1answer
105 views

TMS9918ANL question

I am working on setting up a TMS9918ANL Video Display Processor. I was wondering if there is any way I can test to see if it is working without having the DRAM hooked up (I have a while before the ...
27
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3answers
4k views

Why did many 9-pin printers use only 8 pins for graphics?

In the answer to another question about printers, the following claim is made about 9-pin printers: The Epson MX-80, upon which many other printers were based, had nine round pins which were ...
1
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1answer
194 views

Using Bresenham's circle algorithm (or another alternative algorithm) to draw an arc [closed]

I'm trying to create some graphics function for a ZX Spectrum (Z80) machine in assembler. I already have the basics except for the arc. I know that there must be some way to draw an arc using the ...
20
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3answers
3k views

Typical dpi of dot matrix printers available in the 1980s

I have several printouts from what is presumably a dot-matrix printer, dated 1987. When zoomed in on these, you see the usual stair-step patterns on diagonal lines. However, it's difficult to ...
1
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0answers
151 views

Thinking through the design of a TTL video card: what memory chips and how to manage memory? [closed]

Inspired by Ben Eater's "Let's build a video card" aka "World's worst video card" two part projects on YouTube, I was inspired to consider designing a display adapter for my passive backplane TTL mini-...
9
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7answers
1k views

What are principles of vector CRT display? Simplest way to drive CRTs?

I am into playing with TTL to build 1970s style minicomputers. Aside from talking to them via some serial (or parallel) I/O port to a terminal, I am wondering about display output. This here is about ...
8
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1answer
465 views

Was there ever a functional EGA emulator for the Hercules graphics card?

I used to use a CGA emulator (don't remember which one it was), that could show some gfx even in EGA/VGA-only games (when I selected EGA mode). I remember my frustration seeing some garbled graphics ...
8
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1answer
315 views

Which computers used the Intel 82786 graphics chips, and what sort of commercial success did that chip attain?

In the late 1980's, Intel offered the 82768 graphics chip, with specific support for windowed environments. I remember it being covered in Byte magazine, but don't remember seeing any applications of ...
2
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1answer
101 views

Printing on the graphics screen with lowercase/uppercase letters using CHAR command in Commodore BASIC 7.0

The CHAR command in Commodore BASIC 7.0 on the Commodore 128 allows printing a text at a given position on the screen. Other than the PRINT command, CHAR also works in Hires graphics mode. Since the ...
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0answers
144 views

First GPU with thermal throttling

Pretty much the title - what was the first GPU that reduced clock speeds when it started to overheat instead of simply locking up? Bonus points for first Intel and AMD CPUs too.
4
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1answer
247 views

Hardware implementation of the isometric tile engine. Is it possible, did it exist?

We are talking about a hardware (and not software over hardware, as for example in some games on the SNES console) tile engine with multi-overlapping rectangular (rather than square, when the image ...
5
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2answers
336 views

Two graphics cards for retro gaming

I'm considering installing two graphics cards in my retro gaming setup (one AGP and one PCI) and was wondering if there are any drawbacks to doing so? The main things I'm thinking about are power ...
22
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4answers
4k views

Why was NEC able to wrestle PC graphics standards away from IBM?

The dominant standards for PC graphics in the 1980s were the ones introduced by IBM. This included MDA and CGA with the original IBM PC, followed by EGA shortly after the PC/AT, and then VGA with the ...
18
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3answers
4k views

Are pixels on the Commodore 64 square?

Are "tile pixels" the same size as "sprite pixels", and are they both square (ignoring the rule that multicolor sprites can only be colored in groups of two pixels)? By "square" I mean that the ...
3
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1answer
229 views

The Sentinel (aka The Sentry) on Commodore 64 - why was scrolling so fast?

On the Commodore 64 3D games which use one of the bitmap screen modes were notoriously slow. However watching a gameplay video of The Sentinel will show that in the first-person view, looking around ...
11
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2answers
2k views

How did most fifth-generation consoles avoid wobbly graphics?

According to Why do 3D models on the PlayStation 1 “wobble” so much? the PlayStation had a problem with wobbly graphics because Filling a triangle involves visiting every pixel within it and deciding ...
10
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2answers
1k views

What DOS games used Mode X as described by Michael Abrash?

In Michael Abrash's Graphics Programming Black Book, many chapters are dedicated to fast drawing of primitives, fills and copies using the 320x240 256-colour Mode X. What MS-DOS games used Mode X? ...
4
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1answer
578 views

Why did the PlayStation 2 implement backward compatibility that way?

It is well known that the PlayStation 2 implemented compatibility with the previous console by essentially incorporating a PS1 on a chip. The fact of backward compatibility is unremarkable as far as ...
4
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0answers
124 views

Annotated die photo of 3D graphics chip

I'm interested in how graphics hardware has worked at different tech levels. Having looked at an annotated die photo of the VIC-II for example, I now feel I have a much better understanding of how it ...
31
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3answers
3k views

How did Elite do vertex transformation?

In 3D graphics, vertex transformation is the process of converting x,y,z coordinates in 3D space, to x,y coordinates on the screen. According to https://www.khronos.org/opengl/wiki/...
17
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1answer
993 views

Can you split resolutions and scrolling (horizontally) on an Amiga?

Some time back I asked if it was possible to get more than 8 sprites on a single scanline with the Amiga using a copper list. It seems it is quite possible indeed! Now I am wondering if it is ...
10
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4answers
1k views

What graphics sytems used display lists?

As near as I can tell, there seems to have been roughly speaking two schools of thought when it comes to graphics hardware among early consoles, what I will call the Atari and Texas Instruments ...
10
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2answers
550 views

What PC graphics tech outperformed Sega Dreamcast in 1999?

The Sega Dreamcast was released in 1999 (1998 in Japan) at just the time that the competition for 3D graphics on PCs was intensifying. It's my assumption that a high-end 1999 Pentium II PC with 3Dfx ...
28
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1answer
10k views

Did the Windows 95 screensavers use hardware acceleration APIs?

The windows 95 is known for introducing a couple of classic screensavers including: Maze, Pipes and starfield among others. It looks like DirectX is a collection of multimedia APIs but for this ...
7
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2answers
848 views

Were any DOS games (or software) known to use VBE/AF?

Were there any MS-DOS games or graphics software that were known to take advantage of VESA BIOS Extensions/Accelerator Functions (VBE/AF)? some of the functions defined in the standard are ... Bit ...
43
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2answers
9k views

Why were some early PC 3D cards unsuitable for 2D graphics?

Some of the early PC 3D graphics cards such as the 3dfx Voodoo Graphics cards had a passthrough port to enable them to switch to a secondary card to display 2D graphics. I am curious to know why these ...
5
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3answers
459 views

How to use HGR2 (or HGR) on an Apple II

I am a big fan of the TV show lost, and I was trying to make the Dharma Initiative logo. But at certain point I couldn't add new lines of code and the final part of the logo was cut off. I tried to ...
27
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2answers
11k views

Looking for PC graphics demo software from the early 90s called “Unreal”

Back in the early 90's I remember downloading a graphics demo called, I think, "Unreal". This was on DOS on a standard PC and probably downloaded from a BBS. Identifying information: It ran for ...
13
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4answers
2k views

Amiga 500 OCS/ECS vs Mega Drive VDP

Superficially the Amiga 500 and Mega Drive are similar. Both run a Motorola 68000 CPU at similar clocks and both have dedicated hardware for sprite and other graphics operations. Comparing the arcade ...
54
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6answers
15k views

Why do old games use flashing as means of showing damage?

When you play old games, especially platformers, a common "special effect" is rapid blinking of your character when they are hit. Also, enemies often blinked before dying. Not all games did this, but ...
6
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4answers
2k views

High-end PC graphics circa 1990?

I remember CAD being a major driver for PCs with high-end graphics cards; specifically AutoCAD was rising quickly in popularity around 1990 as PCs were able to compete with very costly CAD ...
54
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6answers
12k views

How did old MS-DOS games utilize various graphic cards?

Nowadays each graphic card has some driver in operating system that translates some (typically) standard API such as OpenGL, so that programmers use some standardized API code to tell graphics cards ...
24
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2answers
6k views

What is a subpixel in Super Mario Bros, and how does it relate to wall clipping?

What are "subpixels" in Super Mario Bros on the NES? How does it relate to wall clipping? At 4:42 in the following video, the notion is mentioned in the context of how it relates to "wall clipping": ...
20
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3answers
3k views

When and what was the first 3D acceleration device ever released?

Plain and simple, we know that consumer level 3D acceleration devices roughly appeared in the middle of the 90s, with brands like Matrox, 3DFX, Nvidia and so on. However, such technology for sure ...
11
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2answers
522 views

Looking for ATARI-ST Graphics Image

I am hoping that someone here collects computer images from days gone by. Many years ago when I used my ATARI-ST I made two drawing I believe I used the art program NEOCHROME, or possibly DEGAS. The ...
18
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2answers
888 views

Fate of mystery Motorola RMS graphics chipset (68486 + 68487)

I recently learned that mid 1980s, Motorola was working on a discrete graphics chipset that would be a great leap forward from its 6847 Video Display Generator and 6845 display controller. It was ...
32
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2answers
5k views

How did Elite on the NES work?

Elite was one of the earliest 3D games, wireframe only of course but still a remarkable accomplishment on 8-bit computers. Originating on the BBC micro, it was ported to many home computers, as well ...
4
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0answers
154 views

What would happen if the DHR jumper was enabled on a Rev A Apple //e?

The Apple //e originally did not support Double HiRes graphics (DHR). The engineers realized they could double their hires and lores X resolution shortly after the introduction of the machine, so the ...
18
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3answers
4k views

When did hardware antialiasing start being available?

An important step towards 3D gaming was the ability to scale sprites or tiles by nonintegral factors. Examples of the former from the eighties were the arcade games Pole Position, Outrun, Space ...
2
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1answer
584 views

SNES PPU die photo

The heart of many classic home computers and game consoles was the graphics chip, yet these tend to be less well-documented than the corresponding CPUs. Still, there are die photos of two of the most ...
6
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3answers
678 views

Can the Commodore 64 display 26 rows of text?

I seem to remember some demo, or a game, which displayed 26 rows of text (that's one more than the usual text mode resolution of 40x25). My memory of it is very hazy, but at least is corroborated by ...
7
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3answers
592 views

Why do we need to acknowledge the interrupt from VIC-II?

A page on how to do raster interrupts includes the following code Irq: LDA #7 STA $D020 ; Turn screen frame yellow LDX #90 Pause: DEX BNE Pause ; Empty loop that "...
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2answers
708 views

Does anyone have an x86 EGA draw pixel routine?

So far, I have gotten by with using the BIOS draw-pixel routine here: http://stanislavs.org/helppc/int_10-c.html This works of course, but I can't imagine that commercial games used this BIOS call as ...
5
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2answers
714 views

How to exactly sync to the raster line for a vertical raster split?

Motivated by Wilson's question Can a Commodore 64 use two screenmodes on one scanline? I tried to implement a simple example that polls the beginning of a rasterline and then switches the screen mode ...
3
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3answers
678 views

Daisy wheel graphics using the period?

Although it would have absolutely beaten the hardware to death, did anyone ever try to write a graphics driver for daisy wheel printers that would use the period symbol to painstakingly construct a ...
7
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2answers
387 views

Could a 6502 use different speeds of RAM in a single machine?

I'm not sure I've entirely formed the idea in my head, but I'll ask anyway... One of the things I learned here in RO is that the BBC gained speed by using faster RAM, thereby avoiding cycle stealing ...
3
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2answers
732 views

EGA style 16 color dithering

I am trying to write a program in C# that will re-create the type of dithering used in many of the old sierra and Lucas arts games. I have looked up many different dithering algorithms and none seem ...