# Search:

Type: Posts; User: esapir

1. ## Thread: Calculating orthographic matrix parameters from perspective matrix

by esapir
Replies
1
Views
451

### Calculating orthographic matrix parameters from perspective matrix

I have the following two matrix creation methods:

GLK_INLINE GLKMatrix4 GLKMatrix4MakePerspective(float fovyRadians, float aspect, float nearZ, float farZ)
{
float cotan = 1.0f /...
2. ## Thread: Finding intersection of a ray with arbitrary surface

by esapir
Replies
2
Views
755

### Finding intersection of a ray with arbitrary surface

I want to check if a user clicked on a surface. In this case the surface is a coons patch.

What should be the algorithm to finding an intersection of the click point (a ray) with the surface?
3. ## Thread: Creating a surface from a closed path composed from bezier curves

by esapir
Replies
1
Views
711

### Creating a surface from a closed path composed from bezier curves

I have a closed path, composed of N bezier curves with 3D coordinates. I would like to create a triangulated surface from this path.
Is there a known algorithm for creating a surface from such a...
4. ## Thread: Creating smooth curve from sampled points

by esapir
Replies
0
Views
582

### Creating smooth curve from sampled points

I am creating sort of a 'paint' application in which use can draw free curves. If i draw the sampled points as is, the curve does not look smooth.

I tried the algorithm in the following tutorial:...
5. ## Thread: Drawing 3D curve with varying width

by esapir
Replies
1
Views
604

### Drawing 3D curve with varying width

I am trying to draw a curve in 3D in which the width may vary. I am doing something similar to what described in the following tutorial:...
6. ## Thread: Drawing lines with changing width

by esapir
Replies
1
Views
575

### Drawing lines with changing width

I am looking for a way to draw 3D lines with changing width. I know that i can create triangles, as in the following tutorial:...
7. ## Thread: Blended lines do not look as expected

by esapir
Replies
5
Views
1,070

### My background is a gradient drawn using two...

My background is a gradient drawn using two rectangles (colors of the vertices with y=0 are not equals to the colors of the vertices with y=height). If i understand correctly, the fog color i use...
8. ## Thread: Blended lines do not look as expected

by esapir
Replies
5
Views
1,070

### It am not sure how to make it work when i have a...

It am not sure how to make it work when i have a gradient background - the fog color changes from pixel to pixel.
How i can i achieve the fog effect without using alpha blending?
9. ## Thread: Blended lines do not look as expected

by esapir
Replies
5
Views
1,070

### Blended lines do not look as expected

I use the following fragment shader, which uses the fog effect, to draw my scene:

precision mediump float;

uniform int EnableFog;
uniform float FogMinDist;
uniform float FogMaxDist;
...
10. ## Thread: Drawing smoothly connected lines with width

by esapir
Replies
2
Views
803

### Drawing smoothly connected lines with width

I am trying to draw lines that should be and look connected. The problem is that when the width is not 1.0, the edges don't really look connected.
Is there a way to fix it without drawing the lines...

by esapir
Replies
3
Views
775

### How i can draw a quad with screen coords?

How i can draw a quad with screen coords?

by esapir
Replies
3
Views
775

### Drawing background gradient

I would like to set the background with gradient instead of a single color. Is it possible ?
13. ## Thread: One vertex buffer with varying with

by esapir
Replies
2
Views
621

### Thanks, i will try that

Thanks, i will try that
14. ## Thread: One vertex buffer with varying with

by esapir
Replies
2
Views
621

### One vertex buffer with varying with

I would like to draw lines from one vertex buffer but with changing width. Is it possible?

by esapir
Replies
2
Views
1,177

16. ## Thread: How can i make far objects look fading or transparent?

by esapir
Replies
2
Views
1,177

### How can i make far objects look fading or transparent?

Say i have a 3D rectangle, rotated 45 degrees as in the attached screenshot. I would like the lines and the far edge (A) to look fading. Moreover, when i rotate the camera, i want the 'new' far lines...
17. ## Thread: Depth test not working

by esapir
Replies
2
Views
727

### You are correct of course. I had another bug that...

You are correct of course. I had another bug that i fixed after that.
All works well now. thanks!
18. ## Thread: Depth test not working

by esapir
Replies
2
Views
727

### Depth test not working

I am using OpenGL ES 2.0 on iOS. I enabled DEPTH_TEST, but still object that should be hidden are rendered.
See screenshots:

http://postimg.org/image/9kp5ltcx7/50d44327/...
19. ## Thread: Triangulating a surface constructed by 3D curves

by esapir
Replies
5
Views
2,404

### It was also my intuition - that i need to...

It was also my intuition - that i need to construct quads. However, there are several problems that i am not sure how to solve:

1. Number of points on the curves is not equal and more than that -...
20. ## Thread: Triangulating a surface constructed by 3D curves

by esapir
Replies
5
Views
2,404

### I think this kind of solution will work only for...

I think this kind of solution will work only for planar polygons. I don't think it will work for real 3D polygons
21. ## Thread: Triangulating a surface constructed by 3D curves

by esapir
Replies
5
Views
2,404

### Triangulating a surface constructed by 3D curves

I have a 3D polygon (i wonder if polygon is the correct term here) that is constructed from 3D curves. These curves are basically lists of 3D points.

I would like to triangulate this surface so i...
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