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/*
* Copyright (C) 2018-2020 - Vito Caputo - <vcaputo@pengaru.com>
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 3 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <SDL.h>
#include <play.h>
#include <stage.h>
#include "glad.h"
#include "plasma-node.h"
#include "shader-node.h"
static const char *plasma_vs = ""
"#version 120\n"
"attribute vec3 vertex;"
"attribute vec2 texcoord;"
"void main()"
"{"
" gl_TexCoord[0].xy = texcoord;"
//" gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;"
" gl_Position = vec4(vertex, 1.f);"
"}"
"";
// derived from https://www.bidouille.org/prog/plasma
static const char *plasma_fs = ""
"#version 120\n"
"#define PI 3.1415926535897932384626433832795\n"
"uniform float alpha;"
"uniform float time;"
"void main() {"
" float v;"
" float stime = sin(time * .01f) * 100.f;"
" vec2 c = gl_TexCoord[0].st;"
// this zooms the texture coords in and out a bit with time
" c *= (sin(stime * .01f) *.5f + .5f) * 3.f + 1.f;"
// plasma calculations, stime instead of time directly to vary directions and speed
" v = sin((c.x + stime));"
" v += sin((c.y + stime) * .5f);"
" v += sin((c.x + c.y +stime) * .5f);"
" c += vec2(sin(stime * .33f), cos(stime * .5f)) * 3.f;"
" v += sin(sqrt(c.x * c.x + c.y * c.y + 1.f) + stime);"
" vec3 col = vec3(cos(PI * v + sin(time)), sin(PI * v + cos(time * .33f)), cos(PI * v + sin(time * .66f)));"
" gl_FragColor = vec4(col * .5f + .5f, alpha);"
"}"
"";
static void plasma_uniforms(void *uniforms_ctxt, void *render_ctxt, unsigned n_uniforms, const int *uniforms, const m4f_t *model_x, float alpha)
{
play_t *play = render_ctxt;
glUniform1f(uniforms[0], alpha);
glUniform1f(uniforms[1], play_ticks(play, PLAY_TICKS_TIMER0) * .001f); // FIXME KLUDGE ALERT
}
/* create plasma rendering stage */
stage_t * plasma_node_new(const stage_conf_t *conf)
{
return shader_node_new_src(conf, plasma_vs, plasma_fs, NULL, plasma_uniforms, NULL, 2,
(const char *[]){
"alpha",
"time",
}
);
}
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