going from immediete mode to vertex array

OpenGL OpenGL: Basic Coding
1

Hi! I’ve been using immediate mode for some time, and reading my vertex and faces from my 3ds loader, though now im going on to vertex arrays, what i wonder about is how the array is built,

for what it seems, its adding x,y,z,x,y,z,x,y,z in a one dimensional array, though the result i had with it was not good.

(pseudo)
so doing a for loop, f.exm for (vertxcounter=0;vertexcounter<numvertxes;vertxvounter++)
VertexArray[vertexcounter] = vertx;
VertexArray[vertexcounter+1] = verty;
VertexArray[vertexcounter+2] = vertz;

(vertexarray[numvertx * 3]
would be a mistake i guess? :slight_smile:

2

You are increasing your counter in the for loop with 1, while you enter three values. So, what happens is the following:

VertexArray[0] = vertx0;
VertexArray[1] = verty0;
VertexArray[2] = vertz0;
VertexArray[1] = vertx1; // notice the index of the VertexArray
VertexArray[2] = vertx1;
VertexArray[3] = vertx1;

Instead make the following loop:


for (size_t vertexcounter = 0; vertexcounter < numvertices; ++vertexcounter)
{
  VertexArray[3 * vertexcounter] = vertx;     // indices 0, 3, 6, ...
  VertexArray[3 * vertexcounter + 1] = verty; // indices 1, 4, 7, ...
  VertexArray[3 * vertexcounter + 2] = vertz; // indices 2, 5, 8, ...
}