b=513156; update Canvas 3D to implement WebGL (still disabled by default via configure); r=vlad

content/canvas/src/WebGLContextValidate.cpp

@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+#include "WebGLContext.h"
+
+using namespace mozilla;
+
+/*
+ * Verify that we can read count consecutive elements from each bound VBO.
+ */
+
+PRBool
+WebGLContext::ValidateBuffers(PRUint32 count)
+{
+    GLint len = 0;
+    GLint enabled = 0, size = 4, type = LOCAL_GL_FLOAT, binding = 0;
+    PRBool someEnabled = PR_FALSE;
+    GLint currentProgram = -1;
+    GLint numAttributes = -1;
+
+    MakeContextCurrent();
+
+    // XXX cache this per program
+    gl->fGetIntegerv(LOCAL_GL_CURRENT_PROGRAM, &currentProgram);
+    if (currentProgram == -1) {
+        // what?
+        LogMessage("glGetIntegerv GL_CURRENT_PROGRAM failed: 0x%08x", (uint) gl->fGetError());
+        return PR_FALSE;
+    }
+
+    gl->fGetProgramiv(currentProgram, LOCAL_GL_ACTIVE_ATTRIBUTES, &numAttributes);
+    if (numAttributes == -1) {
+        // what?
+        LogMessage("glGetProgramiv GL_ACTIVE_ATTRIBUTES failed: 0x%08x", (uint) gl->fGetError());
+        return PR_FALSE;
+    }
+
+    // is this valid?
+    if (numAttributes > (GLint) mAttribBuffers.Length()) {
+        // what?
+        LogMessage("GL_ACTIVE_ATTRIBUTES > GL_MAX_VERTEX_ATTRIBS");
+        return PR_FALSE;
+    }
+    PRUint32 maxAttribs = numAttributes;
+
+    for (PRUint32 i = 0; i < maxAttribs; ++i) {
+      WebGLVertexAttribData& vd = mAttribBuffers[i];
+
+      // is this a problem?
+      if (!vd.enabled)
+	continue;
+
+      if (vd.buf == nsnull) {
+	LogMessage("No VBO bound to index %d (or it's been deleted)!", i);
+	return PR_FALSE;
+      }
+
+      GLuint needed = vd.offset + (vd.stride ? vd.stride : vd.size) * count;
+      if (vd.buf->Count() < needed) {
+	LogMessage("VBO too small for bound attrib index %d: need at least %d elements, but have only %d", i, needed, vd.buf->Count());
+	return PR_FALSE;
+      }
+    }
+
+    return PR_TRUE;
+}