# Questions tagged [rasterization]

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1 vote
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### Is there a reason that we have to use homogeneous coordinates in rasterization?

Looking at the pipeline of games, I am confused about the necessity of homogeneous coordinates. For gameplay logic, a 4x3 matrix is enough to handle translation, rotation, and scale. I can't think of ...
227 views

### How to achieve no gaps between triangles in software renderer like in Quake?

I've heard alot that I need to use fixed-point math, top-left rule, etc. to eliminate gaps between triangles but the thing is how did Quake not have any gaps, did it? I've seen Quake's math file and ...
378 views

### Raster Graphics vs Vector graphics

There was this game that I used to play when I was a kid. It's named Another World. It was ahead of its time in graphics, it even has real-time cutscenes on the SNES version. That game does not use ...
429 views

### Barycentric coordinates outputting coordinate outside of triangle

So I am trying to draw and fill a triangle on the screen using the barycentric method, but my barycentric implementation seems to be outputting outside triangle coordinates, why? ...
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1 vote
514 views

### Geometric clipping of triangles intersecting near plane

I was reading about how rasterization works but there is one topic I can't quite understand. After perspective projection, our point is in clip space as I understand it. Now we test all points in a ...
276 views

### Opengl in 500 lines barycentric calculation question

https://github.com/ssloy/tinyrenderer/wiki/Lesson-2-Triangle-rasterization-and-back-face-culling I cannot figure out how we go from uAB-vector + vAC-vector + PA-vector = 0 to the linear system with ...
1 vote
108 views

### Opengl in 500 lines point in triangle question

https://github.com/ssloy/tinyrenderer/wiki/Lesson-2-Triangle-rasterization-and-back-face-culling I am on lesson 2 of the "Opengl in 500 lines" tutorial. I ...
90 views

### How can I draw filled triangles with the illusion of color?

So I have used the code of this website for drawing filled triangles. But I would like to improve my game by adding the illusion of color. Well sadly I made my game for the monochrome Nokia 5110 ...
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1 vote
6k views

### How can I draw filled triangles in C++?

VERY IMPORTANT NOTE: Im trying to fill a triangle. I have already made the 3D part. Sorry if this wasn't understandable. I'm currently trying to create a simple 3D-Engine. Well, I have successfully ...
• 49
322 views

### Can I linear interpolate color along both the X and Y axis of a circle instead of using the distance formula on each individual point?

I've been unable to make it work and I'm not sure whether it's a problem with my code or if this can even be done. I'm sure there is a way to prove whether it is possible mathematically but I don't ...
• 145
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### How to draw a smoother solid-fill circle?

I'm experimenting with drawing circles and have brute-forced a very simple one: Pseduocode: ...
• 145
1 vote
748 views

### Why does my triangle rasterization miss some pixels along one edge?

I am having an issue rasterizing a triangle. The goal is to calculate barycentric coordinates and make the triangle based off those coordinates. I am having an issue with having weird jaggy missing ...
• 31
1k views

### Why is the depth test not done on geometry before rasterization?

It seems the only time depth is used to discard data is during rasterization, i.e. at the fragment level. In the geometry stage, I've only see culling and clipping of vertices. Is it not possible to ...
• 161
2k views

### Parallelism in GPU's rasterization process

Based on this article I understood the base principle inside the Rasterization algorithm: ...
• 143
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### How can I obtain a triangle ID during rasterization?

I want to know the triangle ID of each rendered pixel is coming from. Is there a way to do this in OpenGL?
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### Details of what GPU actually do when clipping in 4D homogeneous space?

I am learning programmable rendering pipeline by implementing a tiny software renderer. I try to implement it in a 'hardware' style. However, I am not familiar with the GPU pipeline and got some ...
• 221
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### Drawing a lines radiating from every angle using Bresenham line algorithm

I am trying to recreate a image like this ... or just each point Using Bresenham line algorithm, but can't seem to able to do so.. The point i receive from my computation doesn't look like a like, ...
• 21
239 views

### Software polygon rasterization with transparency using raw image data

I have an image with shapes in it (squares and triangles with different colors scattered in the image) and I have an algorithm that matches the image and extracts the geometry vertices from image raw ...
• 191
2k views

### How can I rasterize 3D triangles in software?

I am creating a 3D software renderer, and I have a wire frame cube rendering. Now I am working on solid color rendering and I am wondering what an efficient algorithm for shading the contents of the ...
• 113
430 views

### Retro Racing Renderer

While I have a lot of experience with coding SW&HW 3D rasterizers across multiple platforms and eras, I never got to coding a 2D renderer for a non-polygonal racing game with multiple rolling ...
• 244
485 views

### Algorithm to fill a shape defined by 4 pixel points?

I'm developing an application in Unity3D where a user can define 4 pixel points on screen, and what I would like to do is fill this shape with pixels using Unity's SetPixel. While I can do this ...
• 362
264 views

### XNA/C# Convert polygons into tilemap

I'm currently working on my 2D survival game, where the world is infinite and generated by perlin noise. I wanted to also include biomes and this article interested me - http://www-cs-students....
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1 vote
178 views

### Is the rendering of distorted point clouds more complex?

I have two point clouds of n points: A dense ball-shape point cloud with many points inside A spherical point cloud with points on its surface. Is there (really) any difference between rendering (...
• 31
1 vote
822 views

### (XNA) Stretching Images (Sprites) without Blur (Rasterizing?)

thanks for clicking on this question although it has likely one of the most un-specific and confusing titles on this site. I am somewhat new to XNA and I have only posted 1 question on this site ...
2k views

### What coordinates are we passing to pixel shader from vertex shader?

I have read articles about shader programing and understood the very basic knowledge of shader programing. One thing I always get confused is about the texture mapping. What I pass(output) from VS to ...
43k views

### How do you draw a straight line between two points in a bitmap?

I'm playing around with height maps (bitmaps), trying to create some of my own in my game, and for that I need to implement some basic drawing methods. I've quickly realized that drawing straight ...
223 views

### Triangular grid and rendering to a texture (Direct3D 11)

Is it possible to render vertex data from a triangular grid into a texture with a same size (i.e. 3x3 vertices to 3x3 pixels - each pixel is representing one vertex)? Consider following situation. I ...
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1 vote
835 views

### DirectX11 pixel shader in pipeline is missing

I'm writing a program which displays a MS3D model using DirectX, and unfortunately, the result shows nothing on the screen. When I use the Graphics Debugger from Visual Studio 13, I notice that the ...
• 243
208 views

### Keep rasterized pixel amount constant

I have a scene that is rendered from the point of view of the light using an orthographic projection matrix. For an arbitrarily shaped and oriented object that doesn't change its shape or size in ...
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### How does the Direct3D 9 rasterizer determine triangle coverage?

I'm working on a software rasterizer to use in my project. I have implemented one that works well, however, often my rasterizer under or overestimates triangle coverage. I need perfect emulation of ...
• 575
1 vote
2k views

### Fast software color interpolating triangle rasterization technique

I'm implementing a software renderer with this rasterization method, however, I was wondering if there is a possibility to improve it, or if there exists an alternative technique that is much faster. ...
• 176
495 views

### Is there any heuristic to polygonize a closed 2D raster shape with n triangles?

Let's say we have a 2D image black on white that shows a closed geometric shape. Is there any (not naive brute force) algorithm that approximates that shape as closely as possible with n triangles? ...
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