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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>WebGL Text Rendering</title>
    <script src="https://cdn.tailwindcss.com"></script>
    <style>
        #glCanvas {
            display: block;
            background-color: #1a202c;
            border-radius: 0.5rem;
            box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
        }
        
        .control-panel {
            background-color: #2d3748;
            border-radius: 0.5rem;
        }
        
        .text-input {
            background-color: #4a5568;
            color: white;
            border: none;
            border-radius: 0.25rem;
            padding: 0.5rem;
        }
    </style>
</head>
<body class="bg-gray-900 text-gray-200 min-h-screen p-8">
    <div class="max-w-6xl mx-auto">
        <header class="mb-8">
            <h1 class="text-4xl font-bold text-blue-400 mb-2">WebGL Text Rendering</h1>
            <p class="text-gray-400">Rendering text using pure WebGL</p>
        </header>
        
        <div class="grid grid-cols-1 lg:grid-cols-3 gap-8">
            <div class="lg:col-span-2">
                <canvas id="glCanvas" width="800" height="500"></canvas>
            </div>
            
            <div class="control-panel p-6">
                <h2 class="text-xl font-semibold mb-4 text-blue-300">Controls</h2>
                
                <div class="space-y-4">
                    <div>
                        <label class="block text-sm font-medium mb-1" for="textInput">Text Content</label>
                        <input type="text" id="textInput" value="WebGL" class="text-input w-full">
                    </div>
                    
                    <div>
                        <label class="block text-sm font-medium mb-1" for="fontSize">Font Size</label>
                        <input type="range" id="fontSize" min="10" max="200" value="72" class="w-full">
                        <span id="fontSizeValue" class="text-sm">72px</span>
                    </div>
                    
                    <div>
                        <label class="block text-sm font-medium mb-1" for="textColor">Text Color</label>
                        <input type="color" id="textColor" value="#4299e1" class="w-full h-10">
                    </div>
                    
                    <button id="resetBtn" class="bg-blue-600 hover:bg-blue-700 text-white py-2 px-4 rounded transition-colors">
                        Reset Settings
                    </button>
                </div>
            </div>
        </div>
    </div>

    <script>
        document.addEventListener('DOMContentLoaded', function() {
            const canvas = document.getElementById('glCanvas');
            const gl = canvas.getContext('webgl') || canvas.getContext('experimental-webgl');
            
            if (!gl) {
                alert('WebGL not supported in your browser');
                return;
            }

            // Set up controls
            const textInput = document.getElementById('textInput');
            const fontSize = document.getElementById('fontSize');
            const fontSizeValue = document.getElementById('fontSizeValue');
            const textColor = document.getElementById('textColor');
            const resetBtn = document.getElementById('resetBtn');
            
            fontSize.addEventListener('input', () => {
                fontSizeValue.textContent = `${fontSize.value}px`;
                updateText();
            });
            
            textInput.addEventListener('input', updateText);
            textColor.addEventListener('input', updateUniforms);
            
            resetBtn.addEventListener('click', () => {
                textInput.value = 'WebGL';
                fontSize.value = 72;
                fontSizeValue.textContent = '72px';
                textColor.value = '#4299e1';
                updateText();
                updateUniforms();
            });

            // Vertex shader
            const vsSource = `
                attribute vec2 a_position;
                attribute vec2 a_texCoord;
                
                varying vec2 v_texCoord;
                
                void main() {
                    gl_Position = vec4(a_position, 0, 1);
                    v_texCoord = a_texCoord;
                }
            `;

            // Fragment shader (simplified for basic text rendering)
            const fsSource = `
                precision mediump float;
                
                uniform sampler2D u_texture;
                uniform vec3 u_textColor;
                
                varying vec2 v_texCoord;
                
                void main() {
                    vec4 texColor = texture2D(u_texture, v_texCoord);
                    gl_FragColor = vec4(u_textColor, texColor.r);
                }
            `;

            // Compile shader
            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('Shader compile error:', gl.getShaderInfoLog(shader));
                    gl.deleteShader(shader);
                    return null;
                }
                
                return shader;
            }

            // Create shader program
            const vertexShader = compileShader(gl, vsSource, gl.VERTEX_SHADER);
            const fragmentShader = compileShader(gl, fsSource, gl.FRAGMENT_SHADER);
            
            const program = gl.createProgram();
            gl.attachShader(program, vertexShader);
            gl.attachShader(program, fragmentShader);
            gl.linkProgram(program);
            
            if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
                console.error('Program link error:', gl.getProgramInfoLog(program));
                return;
            }
            
            gl.useProgram(program);

            // Get attribute and uniform locations
            const positionAttributeLocation = gl.getAttribLocation(program, 'a_position');
            const texCoordAttributeLocation = gl.getAttribLocation(program, 'a_texCoord');
            const textureUniformLocation = gl.getUniformLocation(program, 'u_texture');
            const textColorUniformLocation = gl.getUniformLocation(program, 'u_textColor');

            // Create a texture
            const texture = gl.createTexture();
            gl.bindTexture(gl.TEXTURE_2D, texture);
            
            // Set texture parameters
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);

            // Create buffers for a fullscreen quad
            const positionBuffer = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
            
            // Positions for a fullscreen quad
            const positions = [
                -1.0, -1.0,
                 1.0, -1.0,
                -1.0,  1.0,
                 1.0,  1.0,
            ];
            
            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(positions), gl.STATIC_DRAW);

            // Texture coordinates buffer
            const texCoordBuffer = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, texCoordBuffer);
            
            const texCoords = [
                0.0, 0.0,
                1.0, 0.0,
                0.0, 1.0,
                1.0, 1.0,
            ];
            
            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(texCoords), gl.STATIC_DRAW);

            // Create a temporary canvas for text rendering
            const tempCanvas = document.createElement('canvas');
            const tempCtx = tempCanvas.getContext('2d');

            // Generate texture from text
            function generateTextTexture(text, size) {
                // Calculate canvas size based on text
                tempCtx.font = `${size}px Arial`;
                const metrics = tempCtx.measureText(text);
                const width = Math.max(128, metrics.width + 20);
                const height = size + 20;
                
                tempCanvas.width = width;
                tempCanvas.height = height;
                
                // Clear and draw text
                tempCtx.clearRect(0, 0, width, height);
                tempCtx.font = `${size}px Arial`;
                tempCtx.textAlign = 'center';
                tempCtx.textBaseline = 'middle';
                tempCtx.fillStyle = 'white';
                tempCtx.fillText(text, width/2, height/2);
                
                // Upload to WebGL texture
                gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, tempCanvas);
                
                return {
                    width: width,
                    height: height
                };
            }

            // Update uniforms
            function updateUniforms() {
                const color = hexToRgb(textColor.value);
                gl.uniform3f(textColorUniformLocation, color.r, color.g, color.b);
                render();
            }

            // Hex to RGB conversion
            function hexToRgb(hex) {
                const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
                return result ? {
                    r: parseInt(result[1], 16) / 255,
                    g: parseInt(result[2], 16) / 255,
                    b: parseInt(result[3], 16) / 255
                } : { r: 0, g: 0, b: 0 };
            }

            // Update text
            function updateText() {
                const text = textInput.value || ' ';
                const size = parseInt(fontSize.value);
                generateTextTexture(text, size);
                updateUniforms();
            }

            // Render function
            function render() {
                gl.clearColor(0.1, 0.1, 0.1, 1.0);
                gl.clear(gl.COLOR_BUFFER_BIT);
                
                // Enable position attribute
                gl.enableVertexAttribArray(positionAttributeLocation);
                gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
                gl.vertexAttribPointer(positionAttributeLocation, 2, gl.FLOAT, false, 0, 0);
                
                // Enable texture coordinate attribute
                gl.enableVertexAttribArray(texCoordAttributeLocation);
                gl.bindBuffer(gl.ARRAY_BUFFER, texCoordBuffer);
                gl.vertexAttribPointer(texCoordAttributeLocation, 2, gl.FLOAT, false, 0, 0);
                
                // Draw
                gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
            }

            // Initial render
            updateText();
            
            // Handle window resize
            window.addEventListener('resize', function() {
                const displayWidth = canvas.clientWidth;
                const displayHeight = canvas.clientHeight;
                
                if (canvas.width !== displayWidth || canvas.height !== displayHeight) {
                    canvas.width = displayWidth;
                    canvas.height = displayHeight;
                    gl.viewport(0, 0, canvas.width, canvas.height);
                    render();
                }
            });
        });
    </script>
<p style="border-radius: 8px; text-align: center; font-size: 12px; color: #fff; margin-top: 16px;position: fixed; left: 8px; bottom: 8px; z-index: 10; background: rgba(0, 0, 0, 0.8); padding: 4px 8px;">Made with <img src="https://enzostvs-deepsite.hf.space/logo.svg" alt="DeepSite Logo" style="width: 16px; height: 16px; vertical-align: middle;display:inline-block;margin-right:3px;filter:brightness(0) invert(1);"><a href="https://enzostvs-deepsite.hf.space" style="color: #fff;text-decoration: underline;" target="_blank" >DeepSite</a> - 🧬 <a href="https://enzostvs-deepsite.hf.space?remix=victorqueiroz/webgl" style="color: #fff;text-decoration: underline;" target="_blank" >Remix</a></p></body>
</html>