Applying a perspective matrix

Hi,
I'm having problems applying a perspective matrix to my 3d cube in OpenGL (3.3)

I'm uploading the perspective matrix (along with the vertex color) through uniform buffers. I can confirm this uniform buffer process works if I upload the identity matrix, but when I try the perspective variant it does not work (nothing gets drawn),

So when I set the perspective matrix like this:


uint16_t h = mEngine->GetRenderer().GetScreenMode().ScreenHeight;
uint16_t w = mEngine->GetRenderer().GetScreenMode().ScreenWidth;
shaderData.mPerspMatrix = CreatePerspectiveMatrix(45.0f, w/(float) h, 0.5f, 3.0f);


it dosn't work, but when I set it to the identity matrix it draws, but of course with no perspective


shaderData.mPerspMatrix = Mat4(1.0f);


Here's the cube data:


const float vertexPositions[] =
{
// front vertices
0.0f, 0.5f, 0.0f,
0.5f, 0.5f, 0.0f,
0.5f, 0.0f, 0.0f,
0.0f, 0.0f, 0.0f,
// back vertices
0.0f, 0.5f, 0.5f,
0.5f, 0.5f, 0.5f,
0.5f, 0.0f, 0.5f,
0.0f, 0.0f, 0.5f
};
const GLshort indexData[] =
{
// back
5, 4, 7,
5, 7, 6,
// right
1, 5, 6,
1, 6, 2,
// left
0, 4, 7,
0, 7, 3,
// top
5, 4, 0,
5, 0, 1,
// bottom
6, 7, 3,
6, 3, 2,
// front
1, 0, 3,
1, 3, 2
};


Buffer and draw it like this:


// buffer data
glBindBuffer(GL_ARRAY_BUFFER, mVBO_VertexShader);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertexPositions), vertexPositions, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indexData), indexData, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

// setup VAO
glBindVertexArray(mVAO);
glBindBuffer(GL_ARRAY_BUFFER, mVBO_VertexShader);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);


//.... and drawing
glBindVertexArray(mVAO);
glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_SHORT, 0);
glBindVertexArray(0);


Here's my vertex + fragment shader:


const std::string gVertexShader = "#version 330 \n \
\n \
layout(std140) uniform Uni \n \
{ \n \
vec4 mColor; \n \
mat4 mPerspMatrix; \n \
}; \n \
\n \
in vec3 in_position; \n \
out vec3 ex_color; \n \
void main() \n \
{ \n \
vec4 camPos = vec4(in_position, 1.0f); \n \
ex_color = mColor.xyz; \n \
gl_Position = mPerspMatrix * camPos; \n \
} \n";

const std::string gFragmentShader = "#version 330 \n \
in vec3 ex_color; \n \
out vec4 outColor; \n \
void main() \n \
{ \n \
outColor = vec4(ex_color, 1.0f); \n \
} \n";


What am I missing to apply a perspective?

EDIT: Sorry I hope its readable, dosn't seem copy-paste works too well?