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diff --git a/frontend/_rigidbody/2d/part_1.html b/frontend/_rigidbody/2d/part_1.html new file mode 100644 index 0000000..ec0acbf --- /dev/null +++ b/frontend/_rigidbody/2d/part_1.html @@ -0,0 +1,93 @@ +<!DOCTYPE html> +<html lang="en"> + <head> + <meta charset="utf-8"> + <script src="/scripts/jquery-3.5.1.min.js"></script> + <script src="/index.js"></script> + <link rel="stylesheet" href="/index.css"> + <link rel="shortcut icon" href="/favicon/favicon.ico" type="image/x-icon"> + <link href="https://fonts.googleapis.com/css?family=Open+Sans:400,600,300" rel="stylesheet" type="text/css"> + <title>Physics for Games</title> + + <script src="/_shared/math/vec2.js"></script> + <script src="/_shared/math/mat4.js"></script> + <script src="/_shared/math/circle.js"></script> + <script src="/_shared/2d/shader.js"></script> + <script src="/_shared/2d/program_common.js"></script> + <script src="rigidbody_1.js"></script> + </head> + <body> + <header> + <h1>Physics for Games</h1> + </header> + <main> + <nav> + </nav> + <section> + <h1>Part 1: Linear Forces</h1> + <article> + <p> + The first - and perhaps easiest - part of implementing any rigid body physics system is getting the entities in your scene to move in response to linear forces. + With this implementation alone, you can achieve an interesting level of realism in your 2D (and even 3D) scene. + </p> + <p> + Let's begin by recalling the relationships between acceleration, velocity, and position. + </p> + <p> + Knowing all this, you should be able to understand the following source code fairly easily; + <pre> + <code> + <span class="code_keyword">function</span> update(dtSeconds) { + <span class="code_comment">// Add up the forces acting on the circle</span> + <span class="code_keyword">const</span> GRAVITY = 9.8; + <span class="code_keyword">const</span> lGravityForce = vec2(0, -1.0 * (lCircle.mass * <span class="code_constant">GRAVITY</span>)); + lCircle.force = addVec2(lCircle.force, lGravityForce); + + <span class="code_comment">// Figure out acceleration (a = F / m)</span> + <span class="code_keyword">const</span> lCurrentAcceleration = scaleVec2(lCircle.force, 1.0 / lCircle.mass); + + <span class="code_comment">// Calculate the new velocity: v = v0 + a * t</span> + lCircle.velocity = addVec2(lCircle.velocity, scaleVec2(lCurrentAcceleration, dtSeconds)); + + <span class="code_comment">// Update the position based on velocity: x = x0 + v * t</span> + lCircle.position = addVec2(lCircle.position, scaleVec2(lCircle.velocity, dtSeconds)); + + <span class="code_comment">// Update the model matrix accordingly</span> + lCircle.model = translateMatrix(mat4(), lCircle.position.x, lCircle.position.y, 0); + + <span class="code_comment">// Reset the force vector for the next update</span> + lCircle.force = vec2() + } + </code> + </pre> + </p> + <div id="rigidbody_1" class="opengl_canvas_container"> + <canvas width="640" height="480"></canvas> + <div class="opengl_canvas_sidebar"> + <ul class="opengl_value_tracker"> + <li><b>Linear Force:</b><span id="rigidbody_1_force_field">N/A</span></li> + <li><b>Linear Acceleration:</b><span id="rigidbody_1_acceleration_field">N/A</span></li> + <li><b>Linear Velocity:</b><span id="rigidbody_1_velocity_field">N/A</span></li> + <li><b>Linear Position:</b><span id="rigidbody_1_position_field">N/A</span></li> + </ul> + <form id="rigidbody_1_force_submit_button" style="text-align: right; padding: 0.5rem;"> + <div class="vec2_input_group"> + <label>Force Vector</label> + <input class="vec2_x_input" type="number" placeholder="X (Default 0)"/> + <input class="vec2_y_input" type="number" placeholder="Y (Default 5000 N)"/> + </div> + <input type="submit" value="Apply Force"></input> + </form> + </div> + <button class="play_button"> + Play + </button> + <button class="stop_button"> + Stop + </button> + </div> + </article> + </section> + </main> + </body> +</html>
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