GLSL Nearest filter?

[retrotails]

So just to do it, I started a tile renderer in GLSL. Problem is, the filtering fucks everything up. I tried

Code: Select all

texture2D(map, floor((pixel_coords)/size)/size)

it's the closest I could get but it's still blurry before scaling it up with a broken nearest filter.
At the moment, it just adds color to the fragment so I can just test if I can scale up with a nearest neighbor filter.
I'd much rather send a table, but that seems difficult from what I've read.

[monsieur_h]

Your .love doesn't seem to work. I get an error on line 1365 "cannot compile shader".

Details are:

Code: Select all

Line 10: implicit cast from float to vec2
line 11: implicit cast from vec4 to vec3

[retrotails]

Your .love doesn't seem to work. I get an error on line 1365 "cannot compile shader".

Details are:

Code: Select all

Line 10: implicit cast from float to vec2
line 11: implicit cast from vec4 to vec3

Odd, works for me. But thanks for posting the error, could be related.
edit: I see, your card apparently can't convert one vector to another. I can fix the first issue but I don't know how to fix the second.

[Boolsheet]

It's actually GLSL 1.2 that doesn't specify such implicit casts. Only int to float is allowed, I think. Your driver is more lenient and lets it go by.

Can't you use the .rgb (or .xyz, they're identical) swizzler for the second texture2D call too?

[retrotails]

It's actually GLSL 1.2 that doesn't specify such implicit casts. Only int to float is allowed, I think. Your driver is more lenient and lets it go by.

Can't you use the .rgb (or .xyz, they're identical) swizzler for the second texture2D call too?

Ah, so vec3(0,0,0) + 1 doesn't equal vec3(1,1,1), I have to say vec3(0,0,0) + vec3(1,1,1) to be correct?
If so many people can't play like anything with shaders I've made.
I could add the .xyz, but I wasn't sure if that'd fix it since I have no way of testing for it.
By the way, does the video driver compile shaders?

edit: While this topic is up, why does this spit out

Code: Select all

Line 16: error: Undeclared Identifier: col

I'm just trying this shader as a test to see if I can get conditionals working at ALL.

Code: Select all

[[
            uniform sampler2D tex0;
            vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords)
            {
                vec2 uv = vec2(
                    texture_coords.x,
                    1 - texture_coords.y
                );
                if (1 == 1) {
                    vec4 col = vec4(0,0,0,1);
                } else {
                    vec4 col = vec4(1,0,0,1);
                }
             return vec4(col);
            }
        ]]

[Boolsheet]

GLSL 1.2 has special rules for arithmetic operators. See '5.9 Expressions' in the GLSL 1.2 specification. This part is relevant to your question:

One operand is a scalar, and the other is a vector or matrix. In this case, the scalar operation is
applied independently to each component of the vector or matrix, resulting in the same size vector
or matrix.

I can't find anything on type promoting, so I guess arithmetic with different size vectors (like vec4 + vec3) is invalid, but the drivers do it anyway.

By the way, does the video driver compile shaders?

Correct. You can assume that every vendor has their own compiler in their OpenGL implementation and they all have their own little quirks.

Regarding your new problem, it looks like you have some issues with the scope there. Your code would look like this in Lua.

Code: Select all

function effect()
    if (1 == 1) then
        local col = {0,0,0,1}
    else
        local col = {1,0,0,1}
    end
    return col
end

See the problem? Declare the vec4 variable above the if statement so the code inside it can assign the value to that.

[retrotails]

See the problem? Declare the vec4 variable above the if statement so the code inside it can assign the value to that.

Well it gives me some redefinition error. Fortunately I don't have to use a conditional anymore, I have some complex mod() do it instead.

[Boolsheet]

Here's what I hinted at in actual GLSL.

Code: Select all

vec4 col;
if (1 == 1) {
    col = vec4(0,0,0,1);
} else {
    col = vec4(1,0,0,1);
}
return col;