src/streamlit_app.py

import streamlit as st
import streamlit.components.v1 as components
import time

st.title("Shader + Mouse Demo")

# Display mouse coordinates from Streamlit sliders
st.sidebar.subheader("Mouse coordinates (simulate / control)")
mouse_x = st.sidebar.slider("Mouse X (0–1)", 0.0, 1.0, 0.5)
mouse_y = st.sidebar.slider("Mouse Y (0–1)", 0.0, 1.0, 0.5)

# WebGL shader HTML
html_code = f"""
<canvas id="glcanvas" width="500" height="400"></canvas>
<script type="text/javascript">
const canvas = document.getElementById('glcanvas');
const gl = canvas.getContext('webgl');

if (!gl) {{
    alert('WebGL not supported');
}}

// Vertex shader
const vertCode = `
attribute vec4 position;
void main() {{
    gl_Position = position;
}}
`;

// Fragment shader
const fragCode = `
precision mediump float;
uniform float iTime;
uniform vec2 iMouse;
uniform vec2 iResolution;

void main() {{
    vec2 uv = gl_FragCoord.xy / iResolution.xy;
    vec3 color = vec3(uv.x + iMouse.x*0.5 + sin(iTime)*0.2,
                      uv.y + iMouse.y*0.5 + cos(iTime)*0.2,
                      0.5 + 0.5*sin(iTime));
    gl_FragColor = vec4(color, 1.0);
}}
`;

// Compile helper
function compileShader(gl, source, type) {{
    const shader = gl.createShader(type);
    gl.shaderSource(shader, source);
    gl.compileShader(shader);
    if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {{
        console.error(gl.getShaderInfoLog(shader));
        return null;
    }}
    return shader;
}}

// Compile shaders
const vertShader = compileShader(gl, vertCode, gl.VERTEX_SHADER);
const fragShader = compileShader(gl, fragCode, gl.FRAGMENT_SHADER);

// Create program
const program = gl.createProgram();
gl.attachShader(program, vertShader);
gl.attachShader(program, fragShader);
gl.linkProgram(program);
gl.useProgram(program);

// Fullscreen quad
const vertices = new Float32Array([
    -1,-1,  1,-1, -1,1,
    -1,1,   1,-1,  1,1
]);
const buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
const position = gl.getAttribLocation(program, "position");
gl.enableVertexAttribArray(position);
gl.vertexAttribPointer(position, 2, gl.FLOAT, false, 0, 0);

// Uniform locations
const iTime = gl.getUniformLocation(program, "iTime");
const iResolution = gl.getUniformLocation(program, "iResolution");
const iMouse = gl.getUniformLocation(program, "iMouse");

gl.uniform2f(iResolution, canvas.width, canvas.height);

// Animation loop
let startTime = Date.now();
function render() {{
    let t = (Date.now() - startTime) / 1000.0;
    gl.uniform1f(iTime, t);
    gl.uniform2f(iMouse, {mouse_x}, {mouse_y});  // send Streamlit slider values
    gl.drawArrays(gl.TRIANGLES, 0, 6);
    requestAnimationFrame(render);
}}
render();
</script>
"""

components.html(html_code, height=420)
st.write(f"Mouse in Streamlit sliders: X={mouse_x:.2f}, Y={mouse_y:.2f}")