1 files changed, 42 insertions, 0 deletions
diff --git a/blockgame/camera.js b/blockgame/camera.js
new file mode 100644
index 0000000..f696441
--- /dev/null
+++ b/blockgame/camera.js
@@ -0,0 +1,42 @@
+export class Camera {
+	constructor(gl) {
+		const fieldOfView = 45 * Math.PI / 180;   // in radians
+		const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
+		const zNear = 0.1;
+		const zFar = 100.0;
+		const projectionMatrix = mat4.create();
+		
+		// note: glmatrix.js always has the first argument
+		// as the destination to receive the result.
+		mat4.perspective(projectionMatrix,
+		                 fieldOfView,
+		                 aspect,
+		                 zNear,
+		                 zFar);
+		
+		// Set the drawing position to the "identity" point, which is
+		// the center of the scene.
+		const modelViewMatrix = mat4.create();
+		
+		// Now move the drawing position a bit to where we want to
+		// start drawing the square.
+		
+		mat4.translate(modelViewMatrix,     // destination matrix
+		               modelViewMatrix,     // matrix to translate
+		               [-0.0, 0.0, -6.0]);  // amount to translate
+
+		this.mvmatrix = modelViewMatrix;
+		this.pmatrix = projectionMatrix;
+	}
+
+	use(gl, shader) {
+		gl.uniformMatrix4fv(
+		    shader.uniforms.projectionMatrix,
+		    false,
+		    this.pmatrix);
+		gl.uniformMatrix4fv(
+		    shader.uniforms.modelViewMatrix,
+		    false,
+		    this.mvmatrix);
+	}
+}