Merge pull request gpjt#6 from erictheise/updates

Minimal updates to get the lessons working with gl-matrix-2.2.1

.gitignore

@@ -1,3 +1,5 @@
 Thumbs.db
 *.blend1
-.c9settings.xml
+.c9settings.xml
+.DS_Store
+.idea

UPDATES.txt

@@ -0,0 +1,59 @@
+Updates?
+--------
+
+Many people find their way to Giles Thomas' "Learning WebGL Lessons" when first trying to get
+experience using that technology. His sixteen lessons were written between October 2009 and
+December 2010, and they rely on glMatrix-0.9.5.min.js. That library is at version 2.2.1 as of this
+writing (6 July 2014). See the well-organized glMatrix website at http://glmatrix.net/
+
+You'll learn a lot by going through "Learning WebGL Lessons".
+
+You might think you'd learn something by updating the lessons to work with the current version
+of glMatrix, but, in all honesty, you won't.
+
+I've done it. I doubt I'm the first.
+
+Here's an outline of the necessary changes.
+
+* the functionality of mat4.set(mvMatrix, copy) has been replaced with mat4.copy(copy, mvMatrix).
+
+* mat4.toInverseMat3(mvMatrix, normalMatrix) and mat3.transpose(normalMatrix) have been combined
+  into a single method in the mat3 class, mat3.normalFromMat4().
+
+* the API of mat4.perspective() has been rearranged so that
+
+    mat4.perspective(45, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0, pMatrix);
+
+  becomes
+
+    mat4.perspective(pMatrix, 45.0, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0);
+
+* the API for a number of relevant methods now take as arguments the matrix (or vector) to be
+  acted upon and the matrix (or vector) to receive the action. These include mat4.translate(),
+  mat4.rotate(), and mat4.multiply(), and the update is simply to change, for example,
+
+    mat4.translate(mvMatrix, [0.0, 0.0, z]);
+
+  to
+
+    mat4.translate (mvMatrix, mvMatrix, [0.0, 0.0, z]);
+
+* the parameters in the API for vec3.normalize() and vec3.scale() have been reversed, so that
+
+    vec3.normalize(lightingDirection, adjustedLD);
+    vec3.scale(adjustedLD, -1);
+
+  becomes
+
+    vec3.normalize(adjustedLD, lightingDirection);
+    vec3.scale(adjustedLD, adjustedLD, -1);
+
+
+I've also changed the values of z, zoom, or zPos (and, when present, the DOM element, "lightPositionZ")
+to approximate the scene size in the original tutorial, added semicolons when flagged by my IDE, removed
+commas at ends of arrays (this is JavaScript, not Python), and replaced a few occurrences of "= Array()"
+with "= []". I've tried to flag all my changes with "// Update: ...".
+
+Hoping this saves a lot of people a lot of time.
+
+Eric Theise / @erictheise

example01/index.html

@@ -87,7 +87,7 @@
   var gl;
   function initGL(canvas) {
     try {
-      gl = canvas.getContext("experimental-webgl");
+      gl = canvas.getContext("webgl");
       gl.viewportWidth = canvas.width;
       gl.viewportHeight = canvas.height;
     } catch(e) {
@@ -175,7 +175,7 @@
          1.0,  1.0,
         -1.0,  1.0,
          1.0, -1.0,
-        -1.0, -1.0,
+        -1.0, -1.0
     ];
     gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
     vertexPositionBuffer.itemSize = 2;
@@ -188,7 +188,7 @@
       [ 0.7,  1.2],
       [-2.2,  1.2],
       [ 0.7, -1.2],
-      [-2.2, -1.2],
+      [-2.2, -1.2]
   ];
   function drawScene() {
     gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
@@ -214,7 +214,7 @@
 
     gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
 
-    gl.deleteBuffer(plotPositionBuffer)
+    gl.deleteBuffer(plotPositionBuffer);
 
     zoom *= 1.02;
     document.getElementById("zoomOutput").value = zoom;
@@ -243,7 +243,7 @@
 
     var canvas = document.getElementById("example01-canvas");
     initGL(canvas);
-    initShaders()
+    initShaders();
     initBuffers();
 
     gl.clearColor(0.0, 0.0, 0.0, 1.0);