flutter_opengl 0.9.0

Flutter plugin to bind a Texture widget to an OpenGL ES context. Many ShaderToy shaders can be used

example/lib/main.dart

import 'package:flutter/material.dart';
import 'package:flutter_opengl/flutter_opengl.dart';

void main() {
  OpenGLController().initializeGL();
  runApp(const MaterialApp(
    home: MyApp(),
  ));
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  final String fShader = '''
// https://www.shadertoy.com/view/XlfGRj
// Star Nest by Pablo Roman Andrioli

#define iterations 17
#define formuparam 0.53

#define volsteps 20
#define stepsize 0.1

#define zoom   0.800
#define tile   0.850
#define speed  0.010 

#define brightness 0.0015
#define darkmatter 0.300
#define distfading 0.730
#define saturation 0.850


void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
	//get coords and direction
	vec2 uv=fragCoord.xy/iResolution.xy-.5;
	uv.y*=iResolution.y/iResolution.x;
	vec3 dir=vec3(uv*zoom,1.);
	float time=iTime*speed+.25;

	//mouse rotation
	float a1=.5+iMouse.x/iResolution.x*2.;
	float a2=.8+iMouse.y/iResolution.y*2.;
	mat2 rot1=mat2(cos(a1),sin(a1),-sin(a1),cos(a1));
	mat2 rot2=mat2(cos(a2),sin(a2),-sin(a2),cos(a2));
	dir.xz*=rot1;
	dir.xy*=rot2;
	vec3 from=vec3(1.,.5,0.5);
	from+=vec3(time*2.,time,-2.);
	from.xz*=rot1;
	from.xy*=rot2;
	
	//volumetric rendering
	float s=0.1,fade=1.;
	vec3 v=vec3(0.);
	for (int r=0; r<volsteps; r++) {
		vec3 p=from+s*dir*.5;
		p = abs(vec3(tile)-mod(p,vec3(tile*2.))); // tiling fold
		float pa,a=pa=0.;
		for (int i=0; i<iterations; i++) { 
			p=abs(p)/dot(p,p)-formuparam; // the magic formula
			a+=abs(length(p)-pa); // absolute sum of average change
			pa=length(p);
		}
		float dm=max(0.,darkmatter-a*a*.001); //dark matter
		a*=a*a; // add contrast
		if (r>6) fade*=1.-dm; // dark matter, don't render near
		//v+=vec3(dm,dm*.5,0.);
		v+=fade;
		v+=vec3(s,s*s,s*s*s*s)*a*brightness*fade; // coloring based on distance
		fade*=distfading; // distance fading
		s+=stepsize;
	}
	v=mix(vec3(length(v)),v,saturation); //color adjust
	fragColor = vec4(v*.01,1.);	
}
  ''';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: SizedBox(
          width: 400,
          height: 300,
          child: FutureBuilder(
            /// The surface size identifies the real texture size and
            /// it is not related to the above SizedBox size
            future: OpenGLController().openglPlugin.createSurface(300, 200),
            builder: (_, snapshot) {
              if (snapshot.hasError || !snapshot.hasData) {
                return const SizedBox.shrink();
              }
              /// When the texture id is got, it will be possible
              /// to start renderer, set a shader and display it

              /// Start renderer thread
              OpenGLController().openglFFI.startThread();

              /// Set the fragment shader
              OpenGLController().openglFFI.setShaderToy(fShader);

              /// build the texture widget
              return OpenGLTexture(id: snapshot.data!);
            },
          ),
        ),
      ),
    );
  }
}