Is it not possible to use the % operator in the custom shaders?

[Dr. Spankenstein]

Hi folks,

I've got a working shader that creates a scanline effect over an image in Cg. The problem is that the modulo/remainder operator doesn't seem to work when using the shader with Dolphin.

Can anyone please explain why this is the case?

[skid]

drk says try using fmod

[Dr. Spankenstein]

(03-03-2010, 10:04 AM)skid Wrote: drk says try using fmod

fmod works correctly, thank you.

Is it possible to obtain the following in a shader:

1) The image input size (Wii game's input resolution)

2) The texture size for samplerRECT (E.g. 512x512, 64x64 etc.)

in order to line up the scanlines correctly?

Thanks.

---

The following works with Force 4:3 mode at 640x480:

Code:

#define LINES_ON      1
#define LINES_OFF     1
#define OFF_INTENSITY 0.5

uniform samplerRECT samp0 : register(s0);

void main(out float4 ocol0 : COLOR0, in float2 uv0 : TEXCOORD0)
{
    float y_InputSize = 480;
    float y_OutputSize = 480;
    float y_TextureSize = 480;

       float pixelRatio = 20;    //y_OutputSize  * (y_TextureSize / y_InputSize);    

    float mod = fmod(floor(uv0.y * pixelRatio), LINES_ON + LINES_OFF) < LINES_ON ? 1.0 : OFF_INTENSITY;

       ocol0 = texRECT(samp0, uv0) * mod;
}

This code is adopted from an HLSL shader by someone other than myself.

[skid]

Don't know, doc.

How about making each scanline 1 pixel tall and drawn on every other line? Not a true scan-line shader but should look pretty good. At least we would get uniform thickness and spacing.

[Dr. Spankenstein]

(03-03-2010, 01:05 PM)skid Wrote: Don't know, doc.

How about making each scanline 1 pixel tall and drawn on every other line? Not a true scan-line shader but should look pretty good. At least we would get uniform thickness and spacing.

That won't work as the image is still scaled to the screen.

Changing:

Code:

float mod = fmod(floor(uv0.y * pixelRatio), LINES_ON + LINES_OFF) < LINES_ON ? 1.0 : OFF_INTENSITY;

to

Code:

float mod = fmod(uv0.y, 2) < 1 ? 1.0 : OFF_INTENSITY;

does what you ask but doesn't work due to image scaling.