I guess I can just put this up. Most of these have been sitting here forever.

glfuzz.c

@@ -0,0 +1,158 @@
+/*
+	glfuzz.c : Fancy hardware filter.
+	I was bored.
+	(C)2016 Marisa Kirisame, UnSX Team.
+	Released under the GNU GPLv3 (or later).
+*/
+#include <epoxy/gl.h>
+#include <SDL2/SDL.h>
+#include <time.h>
+#include <string.h>
+
+GLuint prog, frag, vert;
+GLuint flat;
+
+const char *vcode =
+"varying vec2 coord;\n"
+"void main()\n"
+"{\n"
+"coord=(gl_Vertex.xy+1.0)*0.5;\n"
+"gl_Position=gl_Vertex;\n"
+"}\n";
+const char *fcode =
+"uniform float timer;\n"
+"uniform vec2 resolution;\n"
+"varying vec2 coord;\n"
+"float rnd(in vec2 sd)\n"
+"{\n"
+"return cos(sd.y*3874.8674+sd.x*6783.5325)*2737.8474;\n"
+"}\n"
+"void main()\n"
+"{\n"
+"vec2 uv=floor(coord*resolution*0.5);\n"
+"vec3 col=vec3(0.71,0.67,0.95)*2.0*abs(fract(rnd(uv)+timer*1.3526)-0.5);\n"
+"uv=floor(coord*resolution*0.25);\n"
+"col*=vec3(0.66,0.84,0.73)*2.0*abs(fract(rnd(uv)+timer*0.7843)-0.5);\n"
+"uv=floor(coord*resolution*0.125);\n"
+"col*=vec3(0.95,0.73,0.81)*2.0*abs(fract(rnd(uv)+timer*0.3725)-0.5);\n"
+"gl_FragColor=vec4(col,1.0);\n"
+"}\n";
+
+float t = 0.f;
+const int fw = 640, fh = 480;
+
+SDL_Window *w;
+SDL_GLContext *ctx;
+
+#define NANOS_SEC 1000000000L
+
+long ticker( void )
+{
+	struct timespec ts;
+	clock_gettime(CLOCK_MONOTONIC_RAW,&ts);
+	return ts.tv_nsec+ts.tv_sec*NANOS_SEC;
+}
+
+void DrawFrame( void )
+{
+	GLint uf;
+	glUseProgram(prog);
+	uf = glGetUniformLocation(prog,"timer");
+	glUniform1f(uf,t);
+	uf = glGetUniformLocation(prog,"resolution");
+	glUniform2f(uf,fw,fh);
+	glEnableClientState(GL_VERTEX_ARRAY);
+	glBindBuffer(GL_ARRAY_BUFFER,flat);
+	glVertexPointer(3,GL_FLOAT,0,0);
+	glDrawArrays(GL_TRIANGLE_STRIP,0,4);
+	glFinish();
+}
+
+int main( int argc, char **argv )
+{
+	SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER|SDL_INIT_EVENTS);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION,2);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION,1);
+	w = SDL_CreateWindow("Fuzz (OpenGL)",SDL_WINDOWPOS_UNDEFINED,
+		SDL_WINDOWPOS_UNDEFINED,fw,fh,
+		SDL_WINDOW_OPENGL|SDL_WINDOW_SHOWN);
+	ctx = SDL_GL_CreateContext(w);
+	SDL_GL_SetSwapInterval(!((argc>1)&&!strcmp(argv[1],"--novsync")));
+	GLint len, suc;
+	char *log;
+	/* fragment */
+	frag = glCreateShader(GL_FRAGMENT_SHADER);
+	len = strlen(fcode);
+	glShaderSource(frag,1,&fcode,&len);
+	glCompileShader(frag);
+	glGetShaderiv(frag,GL_COMPILE_STATUS,&suc);
+	if ( !suc )
+	{
+		glGetShaderiv(frag,GL_INFO_LOG_LENGTH,&len);
+		log = malloc(len);
+		glGetShaderInfoLog(frag,len,&suc,log);
+		printf("fragment:\n%s\n",log);
+		free(log);
+	}
+	/* vertex */
+	vert = glCreateShader(GL_VERTEX_SHADER);
+	len = strlen(vcode);
+	glShaderSource(vert,1,&vcode,&len);
+	glCompileShader(vert);
+	glGetShaderiv(vert,GL_COMPILE_STATUS,&suc);
+	if ( !suc )
+	{
+		glGetShaderiv(vert,GL_INFO_LOG_LENGTH,&len);
+		log = malloc(len);
+		glGetShaderInfoLog(vert,len,&suc,log);
+		printf("vertex:\n%s\n",log);
+		free(log);
+	}
+	/* program */
+	prog = glCreateProgram();
+	glAttachShader(prog,frag);
+	glAttachShader(prog,vert);
+	glLinkProgram(prog);
+	glGetProgramiv(prog,GL_LINK_STATUS,&suc);
+	if ( !suc )
+	{
+		glGetProgramiv(prog,GL_INFO_LOG_LENGTH,&len);
+		log = malloc(len);
+		glGetProgramInfoLog(prog,len,&suc,log);
+		printf("program:\n%s\n",log);
+		free(log);
+	}
+	glDeleteShader(frag);
+	glDeleteShader(vert);
+	/* flat */
+	GLfloat v[12] =
+	{
+		-1.0,-1.0, 0.0,  1.0,-1.0, 0.0,
+		-1.0, 1.0, 0.0,  1.0, 1.0, 0.0,
+	};
+	glGenBuffers(1,&flat);
+	glBindBuffer(GL_ARRAY_BUFFER,flat);
+	glBufferData(GL_ARRAY_BUFFER,sizeof(GLfloat)*12,v,GL_STATIC_DRAW_ARB);
+	SDL_Event e;
+	int active = 1;
+	long tick, tock;
+	while ( active )
+	{
+		while ( SDL_PollEvent(&e) ) if ( (e.type == SDL_QUIT)
+			|| ((e.type == SDL_KEYDOWN)
+			&& (e.key.keysym.sym == SDLK_ESCAPE)) ) active = 0;
+		tick = ticker();
+		DrawFrame();
+		SDL_GL_SwapWindow(w);
+		tock = ticker();
+		float frame = (float)(tock-tick)/NANOS_SEC;
+		printf("FPS: %.2f\n",1.f/frame);
+		t += frame;
+	}
+	glDeleteBuffers(1,&flat);
+	glDeleteProgram(prog);
+	SDL_GL_DeleteContext(ctx);
+	SDL_DestroyWindow(w);
+	SDL_Quit();
+	return 0;
+}