ZDoom

Closing because we got a duplicate on the Github issues.

// #version 330 core
#define SHADERTOY
#ifdef SHADERTOY

#define INPUT_TEXTURE iChannel0
#define MOUSE_POS iMouse.xy
#define VIEW_RESOLUTION iResolution.xy
#define OUTPUT fragColor
#define TEXCOORD fragCoord/iResolution.xy
#define TIMER iTime

#else

#define INPUT_TEXTURE u_scene
#define MOUSE_POS u_mouse
#define VIEW_RESOLUTION u_resolution
#define OUTPUT gl_FragColor
#define TEXCOORD v_texcoord
#define TIMER u_time

uniform sampler2D INPUT_TEXTURE;
uniform vec2 VIEW_RESOLUTION;
uniform vec2 MOUSE_POS;
uniform float TIMER;

in vec2 TEXCOORD;

#endif

#define BLUR_SAMPLES 3
#define MAX_ROTATION .125
#define BLUR_MIX_FACTOR .25

#ifdef SHADERTOY
void mainImage(out vec4 fragColor, in vec2 fragCoord)
#else
void main()
#endif
{
    vec4 colour = texture(INPUT_TEXTURE, TEXCOORD);
    vec2 mousePos = MOUSE_POS / VIEW_RESOLUTION * 2. - 1.;
    /*
    float ef1 = min(v_texcoord.x, v_texcoord.y);
    float ef2 = 1 - max(v_texcoord.x, v_texcoord.y);
    float edgeFactor = min(ef1, ef2) * 2;
    */
    for (int i = BLUR_SAMPLES - 1; i >= 0; i--)
    {
        float th = mousePos.x * float(i + 1) * MAX_ROTATION;
        mat2 rotation = mat2(cos(th), sin(th), -sin(th), cos(th));
        vec2 rotUv = TEXCOORD;
        rotUv -= .5; // Set rotation pivot point
        rotUv = rotation * rotUv; // Rotate
        rotUv += .5; // Don't show the bottom of the screen
        vec4 blurred = texture(INPUT_TEXTURE, rotUv);
        colour = mix(colour, blurred, abs(sin(TIMER)) * BLUR_MIX_FACTOR);
    }
    OUTPUT = colour;
}

I came up with a post-processing shader which should approximate the desired blur effect:

[code]
// #version 330 core
#define SHADERTOY
#ifdef SHADERTOY

#define INPUT_TEXTURE iChannel0
#define MOUSE_POS iMouse.xy
#define VIEW_RESOLUTION iResolution.xy
#define OUTPUT fragColor
#define TEXCOORD fragCoord/iResolution.xy
#define TIMER iTime

#else

#define INPUT_TEXTURE u_scene
#define MOUSE_POS u_mouse
#define VIEW_RESOLUTION u_resolution
#define OUTPUT gl_FragColor
#define TEXCOORD v_texcoord
#define TIMER u_time

uniform sampler2D INPUT_TEXTURE;
uniform vec2 VIEW_RESOLUTION;
uniform vec2 MOUSE_POS;
uniform float TIMER;

in vec2 TEXCOORD;

#endif

#define BLUR_SAMPLES 3
#define MAX_ROTATION .125
#define BLUR_MIX_FACTOR .25

#ifdef SHADERTOY
void mainImage(out vec4 fragColor, in vec2 fragCoord)
#else
void main()
#endif
{
vec4 colour = texture(INPUT_TEXTURE, TEXCOORD);
vec2 mousePos = MOUSE_POS / VIEW_RESOLUTION * 2. - 1.;
/*
float ef1 = min(v_texcoord.x, v_texcoord.y);
float ef2 = 1 - max(v_texcoord.x, v_texcoord.y);
float edgeFactor = min(ef1, ef2) * 2;
*/
for (int i = BLUR_SAMPLES - 1; i >= 0; i--)
{
float th = mousePos.x * float(i + 1) * MAX_ROTATION;
mat2 rotation = mat2(cos(th), sin(th), -sin(th), cos(th));
vec2 rotUv = TEXCOORD;
rotUv -= .5; // Set rotation pivot point
rotUv = rotation * rotUv; // Rotate
rotUv += .5; // Don't show the bottom of the screen
vec4 blurred = texture(INPUT_TEXTURE, rotUv);
colour = mix(colour, blurred, abs(sin(TIMER)) * BLUR_MIX_FACTOR);
}
OUTPUT = colour;
}
[/code]

I developed it using ShaderToy and [url=https://github.com/patriciogonzalezvivo/glslViewer]GLSLViewer[/url]. You can copy and paste the code into ShaderToy to see what it looks like. On a laptop with a crappy Intel integrated GPU, I get 60FPS on ShaderToy.

That's all good, thanks for the quick reply :)

I still haven't gotten around to this.

@Rachael just wondering if this is something you ever got around to checking out? I know you're completely strapped for time but just thought I'd ask :)

I'll try it out and attempt to make something later on. Right now I have way too much going on.

Another problem is that the speed of the delirium effect is tied to the framerate. I remember the first time I saw it in NBlood I thought it was unnaturally fast.

The bloom effect is 8 blur shaders running in sequence. For a single blur effect you just need two runs (vertical + horizontal) with the gaussian blur shader used by the bloom pass.

I think that's a question where only dpJudas may be able to give an answer.

[quote="Graf Zahl"]This will require a postprocessing shader.[/quote]
Is it even possible to write a blur shader without baking the GPU? None of mine have ever done it unless I sampled at really low resolutions and upsampled the result.

If not for this little issue I'd have happily done it myself.

I know. ;)
This will require a postprocessing shader.

Reminder that this has not been re-implemented yet.