STUDIO/anim1.html at main · DO-SAY-GO/STUDIO · GitHub

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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>3-Point Perspective Cube</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      overflow: hidden;
      background: dodgerblue;
    }

    canvas {
      display: block;
      width: 100vw;
      height: 100vh;
    }

    .debug-checkbox {
      position: absolute;
      top: 1em;
      left: 1em;
      background: rgba(255, 255, 255, 0.8);
      padding: 0.5em;
      border-radius: 4px;
      font-family: Arial, sans-serif;
    }
  </style>
</head>
<body>
  <canvas id="cubeCanvas"></canvas>
  <div class="debug-checkbox">
    <label>
      <input type="checkbox" id="debugLines"> Show Debug Lines
    </label>
  </div>

  <script>
    // Imports, constants then state
    const canvas = document.getElementById('cubeCanvas');
    if (!canvas) {
      console.error('Canvas element not found!');
    }

    const ctx = canvas.getContext('2d');
    if (!ctx) {
      console.error('Failed to get 2D context for Canvas!');
    }

    const debugCheckbox = document.getElementById('debugLines');
    let showDebugLines = false;

    let horizonY = canvas.height * 0.382; // 38.2% from top (61.8% from bottom)
    let vp1 = { x: -canvas.width * 0.5, y: horizonY }; // Left vanishing point (off-screen)
    let vp2 = { x: canvas.width * 1.5, y: horizonY }; // Right vanishing point (off-screen)
    let vp3 = { x: canvas.width / 2, y: canvas.height * 1.5 }; // Top vanishing point (below canvas)
    const perspective = 1000; // Controls depth effect

    const cubeSize = 100; // Side length
    let cube = { center: { x: 0, y: 0, z: -100 }, vertices: [] }; // Single cube
    const cubeFaces = [
      { vertices: [0, 1, 5, 4], color: '#808080' }, // Front
      { vertices: [2, 3, 7, 6], color: '#808080' }, // Back
      { vertices: [0, 3, 7, 4], color: '#808080' }, // Left
      { vertices: [1, 2, 6, 5], color: '#808080' }, // Right
      { vertices: [4, 5, 6, 7], color: '#808080' }, // Top
      { vertices: [0, 1, 2, 3], color: '#808080' }  // Bottom
    ];

    const floor = {
      points: [
        { x: -canvas.width, y: 0, z: 0 },  // Bottom-left
        { x: canvas.width, y: 0, z: 0 },   // Bottom-right
        { x: canvas.width, y: 0, z: -800 }, // Top-right
        { x: -canvas.width, y: 0, z: -800 } // Top-left
      ]
    };

    // Logic
    window.addEventListener('resize', resizeCanvas);
    debugCheckbox.addEventListener('change', () => {
      showDebugLines = debugCheckbox.checked;
      render();
    });
    resizeCanvas();
    initializeCube();
    render();

    // Functions
    function resizeCanvas() {
      canvas.width = window.innerWidth;
      canvas.height = window.innerHeight;
      initializeCube();
      render();
    }

    function initializeCube() {
      const x = 0; // Center in X
      const z = Math.random() * -200; // -200 to 0
      cube.center = { x, y: 0, z };
      cube.vertices = generateCubeVertices(cube.center);
      console.log('Cube positioned at:', cube.center);
    }

    function render() {
      try {
        ctx.clearRect(0, 0, canvas.width, canvas.height);

        // Update perspective parameters
        horizonY = canvas.height * 0.382;
        vp1 = { x: -canvas.width * 0.5, y: horizonY };
        vp2 = { x: canvas.width * 1.5, y: horizonY };
        vp3 = { x: canvas.width / 2, y: canvas.height * 1.5 };

        // Draw floor
        drawFloor();

        // Draw guides
        drawGuides();

        // Sort faces by average z (far to near)
        const sortedFaces = cubeFaces.map(face => {
          const avgZ = face.vertices.reduce((sum, idx) => sum + cube.vertices[idx].z, 0) / face.vertices.length;
          return { face, avgZ };
        }).sort((a, b) => b.avgZ - a.avgZ);

        console.log('Sorted faces by avgZ:', sortedFaces.map(f => f.avgZ));

        // Render sorted faces
        sortedFaces.forEach(({ face }) => {
          drawFace(cube, face);
        });

        // Draw debug lines if enabled
        if (showDebugLines) {
          drawDebugLines();
        }
      } catch (error) {
        console.error('Error in render:', error);
      }
    }

    function project(x, y, z) {
      const d = perspective / (perspective - z);
      if (isNaN(d) || d <= 0) {
        console.error('Invalid projection:', { x, y, z, d });
        return { x: 0, y: 0 };
      }

      const projX = canvas.width / 2 + x * d + (x < 0 ? (vp1.x - canvas.width / 2) * (1 - d) : (vp2.x - canvas.width / 2) * (1 - d));
      const projY = horizonY + y * d + (vp3.y - horizonY) * (1 - d);

      if (isNaN(projX) || isNaN(projY)) {
        console.error('NaN in projection:', { x, y, z, projX, projY, d });
        return { x: 0, y: 0 };
      }
      return { x: projX, y: projY, scale: d };
    }

    function drawFace(cube, face) {
      try {
        ctx.save();
        const points2D = face.vertices.map(index => project(
          cube.vertices[index].x,
          cube.vertices[index].y,
          cube.vertices[index].z
        ));
        ctx.beginPath();
        ctx.moveTo(points2D[0].x, points2D[0].y);
        for (let i = 1; i < points2D.length; i++) {
          ctx.lineTo(points2D[i].x, points2D[i].y);
        }
        ctx.closePath();
        ctx.fillStyle = face.color;
        ctx.fill();
        ctx.strokeStyle = 'black';
        ctx.lineWidth = 2;
        ctx.stroke();
        ctx.restore();

        console.log('Face projected points:', points2D.map(p => ({ x: p.x, y: p.y })));
        if (face.vertices.includes(0)) {
          console.log('Bottom vertex projected Y:', points2D[0].y);
        }
        if (face.vertices.includes(4)) {
          console.log('Top vertex projected Y:', points2D[0].y);
        }
      } catch (error) {
        console.error('Error drawing face:', error);
      }
    }

    function drawFloor() {
      try {
        ctx.save();
        const points2D = floor.points.map(point => project(point.x, point.y, point.z));
        ctx.beginPath();
        ctx.moveTo(points2D[0].x, points2D[0].y);
        for (let i = 1; i < points2D.length; i++) {
          ctx.lineTo(points2D[i].x, points2D[i].y);
        }
        ctx.closePath();
        ctx.fillStyle = '#2A2A2A'; // Charcoal for floor
        ctx.fill();
        ctx.restore();

        console.log('Floor projected points:', points2D.map(p => ({ x: p.x, y: p.y })));
      } catch (error) {
        console.error('Error drawing floor:', error);
      }
    }

    function drawGuides() {
      ctx.save();
      ctx.beginPath();
      ctx.moveTo(0, horizonY);
      ctx.lineTo(canvas.width, horizonY);
      ctx.strokeStyle = 'red';
      ctx.lineWidth = 2;
      ctx.stroke();
      ctx.restore();
    }

    function drawDebugLines() {
      ctx.save();
      ctx.strokeStyle = 'yellow';
      ctx.lineWidth = 1;
      ctx.setLineDash([5, 5]); // Dashed lines

      cube.vertices.forEach((vertex, index) => {
        const point2D = project(vertex.x, vertex.y, vertex.z);

        // Lines to VP1 (left-right edges)
        if (index === 0 || index === 3 || index === 4 || index === 7) { // Left vertices
          ctx.beginPath();
          ctx.moveTo(point2D.x, point2D.y);
          ctx.lineTo(vp1.x, vp1.y);
          ctx.stroke();
          console.log(`Debug line to VP1 from vertex ${index}: (${point2D.x}, ${point2D.y}) to (${vp1.x}, ${vp1.y})`);
        }

        // Lines to VP2 (right-left edges)
        if (index === 1 || index === 2 || index === 5 || index === 6) { // Right vertices
          ctx.beginPath();
          ctx.moveTo(point2D.x, point2D.y);
          ctx.lineTo(vp2.x, vp2.y);
          ctx.stroke();
          console.log(`Debug line to VP2 from vertex ${index}: (${point2D.x}, ${point2D.y}) to (${vp2.x}, ${vp2.y})`);
        }

        // Lines to VP3 (vertical edges)
        ctx.beginPath();
        ctx.moveTo(point2D.x, point2D.y);
        ctx.lineTo(vp3.x, vp3.y);
        ctx.stroke();
        console.log(`Debug line to VP3 from vertex ${index}: (${point2D.x}, ${point2D.y}) to (${vp3.x}, ${vp3.y})`);
      });

      ctx.setLineDash([]); // Reset dash
      ctx.restore();
    }

    // Helper functions
    function generateCubeVertices(center) {
      const { x, y, z } = center;
      const s = cubeSize / 2;
      const theta = Math.PI / 6; // 30 degrees
      const cosTheta = Math.cos(theta);
      const sinTheta = Math.sin(theta);

      const baseVertices = [
        { x: -s, y: 0, z: -s },       // 0: Bottom front left
        { x: s, y: 0, z: -s },        // 1: Bottom front right
        { x: s, y: 0, z: s },         // 2: Bottom back right
        { x: -s, y: 0, z: s },        // 3: Bottom back left
        { x: -s, y: cubeSize, z: -s }, // 4: Top front left
        { x: s, y: cubeSize, z: -s },  // 5: Top front right
        { x: s, y: cubeSize, z: s },   // 6: Top back right
        { x: -s, y: cubeSize, z: s }   // 7: Top back left
      ];

      const rotatedVertices = baseVertices.map(v => {
        const rx = v.x * cosTheta + v.z * sinTheta;
        const rz = -v.x * sinTheta + v.z * cosTheta;
        return {
          x: rx + x,
          y: v.y + y,
          z: rz + z
        };
      });

      console.log('Rotated vertices:', rotatedVertices);
      return rotatedVertices;
    }
  </script>
</body>
</html>