Translating square with shaders on iPhone

I'm trying to update my (little) knowledge of OpenGL ES 1.1 to 2.0 on the iPhone. The default OpenGL ES Application template for the iPhone draws a square and makes it translate up and down and works fine. Their implementation does the math for the Y value changes on the shader itself which is pretty much useless. So, I've changed the vertext shader to:

uniform mat4 mvpMatrix;

attribute vec4 position;
attribute vec4 color;
varying vec4 colorVarying;


void main()
{
    gl_Position = position * mvpMatrix;
    colorVarying = color;
}

Which seems to be correct and common (from I've seen in my research). Obviously, I did the necessary changes to the code, like binding the uniform and, to help with the math, I got the sources for the esUtil.h code. On the drawing method, my code looks like this:

transY += 0.075f;   

ESMatrix mvp, model, view;
esMatrixLoadIdentity(&view);
esPerspective(&view, 60.0, 320.0/480.0, 1.0, -1.0);

esMatrixLoadIdentity(&model);
esTranslate(&model, sinf(transY), 0.0f, 0.0f);

esMatrixLoadIdentity(&mvp);
esMatrixMultiply(&mvp, &model, &view);
glUniformMatrix4fv(uniforms[UNIFORM_MVPMATRIX], 1, GL_FALSE, (GLfloat *)&mvp);

And that should be working but, unfortunate开发者_StackOverflow社区ly, what I get is quite different from a simple translation.

I've restarted the template a few times but I can't figure out what I'm doing wrong here... Rotating seems to be working as expected, I believe...

Any help would be appreciated.

I think you want to reverse the order of your position transform, as your matrix library is probably working in Column-major order.

gl_Position = position * mvpMatrix;

=>

gl_Position = mvpMatrix * position;

unknowingly you have made a camera position change. In opengles camera(global) and object(local) transforms are just inverse.