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TL;DR: How to pass a interpolated double vector, such as a dvec2, from the vertex shader to the fragment shader? I have a vertex shader. In this the output variable out vec2 uv; is set. And i have...
#2: Post edited
by
H_H
·
2023-08-22T16:48:53Z (9 months ago)
Add description and image to explain why `float` isn't precise enough.
- TL;DR: How to pass a interpolated `double` vector, such as a `dvec2`, from the vertex shader to the fragment shader?
- I have a vertex shader. In this the output variable `out vec2 uv;` is set. And i have a fragment shader, in this the (intperpolated) input variable `in vec2 uv;` is expected. This works, and the relevant shader parts looks like this:
- Vertex shader:
- ```
- #version 400
- out vec2 uv;
- ...
- void main()
- {
- uv = calculateUv();
- ...
- }
- ```
- Fragment shader:
- ```
- #version 400
- in vec2 uv;
- ...
- void main()
- {
- doSomething(uv);
- ...
- }
- ```
- However, this uses only `float` or 32 bit precision. When i change it to `double` precision, by using `dvec2` instead of `vec2`, it no longer works and i get a
- > error C7570: 64 bit input 'uv' should be flat
- error. I can set `uv` to `flat`, but then it is no longer interpolated and it doesn't work as expected (the `uv` value is the same for all `fragments` on a face, which is not what i want). Non-working shaders:
- Vertex shader:
- ```
- #version 400
- out dvec2 uv;
- ...
- void main()
- {
- uv = calculateUv();
- ...
- }
- ```
- Fragment shader:
- ```
- #version 400
- in dvec2 uv;
- ...
- void main()
- {
- doSomething(uv);
- ...
- }
- ```
- It isn't a problem of not accepting double in general, inside the shader i can use `double` based types such `dvec2` without any problem as long as i don't want to pass it to a other shader.
- Any idea how to pass a `dvec2`? Or any workaround?
- TL;DR: How to pass a interpolated `double` vector, such as a `dvec2`, from the vertex shader to the fragment shader?
- I have a vertex shader. In this the output variable `out vec2 uv;` is set. And i have a fragment shader, in this the (intperpolated) input variable `in vec2 uv;` is expected. This works, and the relevant shader parts looks like this:
- Vertex shader:
- ```
- #version 400
- out vec2 uv;
- ...
- void main()
- {
- uv = calculateUv();
- ...
- }
- ```
- Fragment shader:
- ```
- #version 400
- in vec2 uv;
- ...
- void main()
- {
- doSomething(uv);
- ...
- }
- ```
- However, this uses only `float` or 32 bit precision. When i change it to `double` precision, by using `dvec2` instead of `vec2`, it no longer works and i get a
- > error C7570: 64 bit input 'uv' should be flat
- error. I can set `uv` to `flat`, but then it is no longer interpolated and it doesn't work as expected (the `uv` value is the same for all `fragments` on a face, which is not what i want). Non-working shaders:
- Vertex shader:
- ```
- #version 400
- out dvec2 uv;
- ...
- void main()
- {
- uv = calculateUv();
- ...
- }
- ```
- Fragment shader:
- ```
- #version 400
- in dvec2 uv;
- ...
- void main()
- {
- doSomething(uv);
- ...
- }
- ```
- It isn't a problem of not accepting double in general, inside the shader i can use `double` based types such `dvec2` without any problem as long as i don't want to pass it to a other shader.
- Why `double` precession is needed: I draw a fractal and want to zoom. This is possible by changing the `uv`-coordinates but at a high zoom level, there are big artefacts from big, pixel-like, regions on the screen having the same `uv` value.
- Any idea how to pass a `dvec2`? Or any workaround?
#1: Initial revision
by
H_H
·
2023-08-22T16:37:55Z (9 months ago)
OpenGL: Pass a double vector from vertex shader to fragment shader
TL;DR: How to pass a interpolated `double` vector, such as a `dvec2`, from the vertex shader to the fragment shader?
I have a vertex shader. In this the output variable `out vec2 uv;` is set. And i have a fragment shader, in this the (intperpolated) input variable `in vec2 uv;` is expected. This works, and the relevant shader parts looks like this:
Vertex shader:
```
#version 400
out vec2 uv;
...
void main()
{
uv = calculateUv();
...
}
```
Fragment shader:
```
#version 400
in vec2 uv;
...
void main()
{
doSomething(uv);
...
}
```
However, this uses only `float` or 32 bit precision. When i change it to `double` precision, by using `dvec2` instead of `vec2`, it no longer works and i get a
> error C7570: 64 bit input 'uv' should be flat
error. I can set `uv` to `flat`, but then it is no longer interpolated and it doesn't work as expected (the `uv` value is the same for all `fragments` on a face, which is not what i want). Non-working shaders:
Vertex shader:
```
#version 400
out dvec2 uv;
...
void main()
{
uv = calculateUv();
...
}
```
Fragment shader:
```
#version 400
in dvec2 uv;
...
void main()
{
doSomething(uv);
...
}
```
It isn't a problem of not accepting double in general, inside the shader i can use `double` based types such `dvec2` without any problem as long as i don't want to pass it to a other shader.
Any idea how to pass a `dvec2`? Or any workaround?