replace the glsl snow shader with a more lightweight version.

(gpu usage is approximately 25% compared to the original.)
This commit is contained in:
aliaspider 2016-12-11 15:52:32 +01:00
parent d8acba1fa8
commit 5cf8391c5a
2 changed files with 68 additions and 57 deletions

View File

@ -1,65 +1,69 @@
#include "shaders_common.h"
static const char *stock_fragment_xmb_snow = GLSL(
uniform float time;
vec2 res = vec2(1920*3, 1080*3);
static const char* stock_fragment_xmb_snow = GLSL(
uniform float time;
uniform vec2 OutputSize;
// High quality = larger patterns
// quality * 84 is the number of seconds in a loop
float quality = 8.0;
float baseScale = 3.5; // [1.0 .. 10.0]
float density = 0.7; // [0.01 .. 1.0]
float speed = 0.25; // [0.1 .. 1.0]
float Cellular2D(vec2 P) {
// https://github.com/BrianSharpe/Wombat/blob/master/Cellular2D.glsl
vec2 Pi = floor(P);
vec2 Pf = P - Pi;
vec4 Pt = vec4( Pi.xy, Pi.xy + 1.0 );
Pt = Pt - floor(Pt * ( 1.0 / 71.0 )) * 71.0;
Pt += vec2( 26.0, 161.0 ).xyxy;
Pt *= Pt;
Pt = Pt.xzxz * Pt.yyww;
vec4 hash_x = fract( Pt * ( 1.0 / 951.135664 ) );
vec4 hash_y = fract( Pt * ( 1.0 / 642.949883 ) );
hash_x = hash_x * 2.0 - 1.0;
hash_y = hash_y * 2.0 - 1.0;
const float JITTER_WINDOW = 0.25;
hash_x = ( ( hash_x * hash_x * hash_x ) - sign( hash_x ) ) * JITTER_WINDOW + vec4( 0.0, 1.0, 0.0, 1.0 );
hash_y = ( ( hash_y * hash_y * hash_y ) - sign( hash_y ) ) * JITTER_WINDOW + vec4( 0.0, 0.0, 1.0, 1.0 );
vec4 dx = Pf.xxxx - hash_x;
vec4 dy = Pf.yyyy - hash_y;
vec4 d = dx * dx + dy * dy;
d.xy = min(d.xy, d.zw);
return min(d.x, d.y) * ( 1.0 / 1.125 );
}
float rand(vec2 co)
{
return fract(sin(dot(co.xy, vec2(12.9898, 78.233))) * 43758.5453);
}
float snow(vec2 pos, float time, float scale) {
// add wobble
pos.x += cos(pos.y*4.0 + time*3.14159*2.0 + 1.0/scale)/(8.0/scale);
// add gravity
pos += time*scale*vec2(-0.5, 1.0);
return max(
1.0 - Cellular2D(mod(pos/scale, scale*quality)*16.0)*1024.0,
0.0
) * (scale*0.5 + 0.5);
}
float dist_func(vec2 distv)
{
float dist = sqrt((distv.x * distv.x) + (distv.y * distv.y)) * (40.0 / baseScale);
dist = clamp(dist, 0.0, 1.0);
return cos(dist * (3.14159265358 * 0.5)) * 0.5;
}
void main( void ) {
float winscale = max(res.x, res.y);
float tim = mod(time/8.0, 84.0*quality);
vec2 pos = gl_FragCoord.xy/winscale;
float a = 0.0;
// Each of these is a layer of snow
// Remove some for better performance
// Changing the scale (3rd value) will mess with the looping
a += snow(pos, tim, 1.0);
a += snow(pos, tim, 0.7);
a += snow(pos, tim, 0.6);
a += snow(pos, tim, 0.5);
a += snow(pos, tim, 0.4);
a += snow(pos, tim, 0.3);
a += snow(pos, tim, 0.25);
a += snow(pos, tim, 0.125);
a = a * min(pos.y*4.0, 1.0);
gl_FragColor = vec4(1.0, 1.0, 1.0, a);
}
float random_dots(vec2 co)
{
float part = 1.0 / 20.0;
vec2 cd = floor(co / part);
float p = rand(cd);
if (p > 0.005 * (density * 40.0))
return 0.0;
vec2 dpos = (vec2(fract(p * 2.0) , p) + vec2(2.0, 2.0)) * 0.25;
vec2 cellpos = fract(co / part);
vec2 distv = (cellpos - dpos);
return dist_func(distv);
}
float snow(vec2 pos, float time, float scale)
{
// add wobble
pos.x += cos(pos.y * 1.2 + time * 3.14159 * 2.0 + 1.0 / scale) / (8.0 / scale) * 4.0;
// add gravity
pos += time * scale * vec2(-0.5, 1.0) * 4.0;
return random_dots(pos / scale) * (scale * 0.5 + 0.5);
}
void main(void)
{
float tim = time * 0.4 * speed;
vec2 pos = gl_FragCoord.xy / OutputSize.xx;
float a = 0.0;
// Each of these is a layer of snow
// Remove some for better performance
// Changing the scale (3rd value) will mess with the looping
a += snow(pos, tim, 1.0);
a += snow(pos, tim, 0.7);
a += snow(pos, tim, 0.6);
a += snow(pos, tim, 0.5);
a += snow(pos, tim, 0.4);
a += snow(pos, tim, 0.3);
a += snow(pos, tim, 0.25);
a += snow(pos, tim, 0.125);
a = a * min(pos.y * 4.0, 1.0);
gl_FragColor = vec4(1.0, 1.0, 1.0, a);
}
);

View File

@ -193,6 +193,13 @@ static void menu_display_gl_draw_pipeline(void *data)
uniform_param.lookup.ident = "time";
uniform_param.result.f.v0 = t;
video_shader_driver_set_parameter(uniform_param);
uniform_param.type = UNIFORM_2F;
uniform_param.lookup.ident = "OutputSize";
uniform_param.result.f.v0 = draw->width;
uniform_param.result.f.v1 = draw->height;
video_shader_driver_set_parameter(uniform_param);
}
break;