Projection and View Matrix

Question

Edit

I have determined it's not a problem with my matrices, rather glGetUniformLocation not finding the requested variable

Edit 2

I've fixed the above mistake and unit matrices now work. So the error goes back to my matrices now I think.

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I am having some issues getting my projection and view matrices correct. I have checked them against several examples and don't know where I am going wrong. I see nothing on screen unless I disable the shader.

I calculate the model matrix like so:

float aspect = (float)width / std::max(1.0f, (float)height);
float top = tan(Maths::toRadian(FOV * 0.5f)) * near;
float bottom = -top;
float right = top * aspect;
float left = -right;

projMatrix.reset();
projMatrix(0, 0) = (2.0f * near) / (right - left);
projMatrix(1, 1) = (2.0f * near) / (top - bottom);
projMatrix(2, 2) = -(far + near) / (far - near);
projMatrix(2, 3) = -1.0f;
projMatrix(3, 2) = (-2.0f * far * near) / (far - near);
projMatrix(3, 3) = 0.0f;

I calculate the view matrix like so:

Camera::Camera(const Maths::Vector3& pos)
    : position(pos), target(0.0f, 0.0f, 0.0f), up(0.0f, 1.0f, 0.0f) {
    target.normalize();
    up.normalize();
}

Maths::Matrix4 Camera::getMatrix() const {
    Maths::Matrix4 mat;
    Maths::Vector3 z = position - target;
    Maths::Vector3 x = Maths::crossProduct(up, z);
    Maths::Vector3 y = Maths::crossProduct(z, x);

    z.normalize();
    x.normalize();

    mat(0, 0) = x.x; mat(0, 1) = y.x; mat(0, 2) = y.z;
    mat(1, 0) = x.y; mat(1, 1) = y.y; mat(1, 2) = y.z;
    mat(2, 0) = x.z; mat(1, 2) = y.z; mat(2, 2) = y.z;

    mat(3, 0) = -Maths::dotProduct(x, position);
    mat(3, 1) = -Maths::dotProduct(y, position);
    mat(3, 2) = -Maths::dotProduct(z, position);

    return mat;
}

Then I pass them into the shader eventually like so:

glGetUniformLocation(viewMatrix, "view");
glGetUniformLocation(projMatrix, "proj");

glUniformMatrix4fv(viewMatrix, 1, GL_TRUE, view.asArray());
glUniformMatrix4fv(projMatrix, 1, GL_TRUE, proj.asArray());

and finally my shader:

Vertex:

#version 330

layout (location = 0) in vec3 position;

uniform mat4 view;
uniform mat4 proj;

void main()
{
    gl_Position = proj * view * vec4(position, 1.0);
};

Fragment:

#version 330

out vec4 gl_FragColor;

void main()
{
    gl_FragColor = vec4(1.0f, 0.0f, 0.0f, 1.0f);
} 

And to cover all bases here are my methods for calculating the dot product and the cross product:

float dotProduct(const Vector3& a, const Vector3& b) {
    return a.x * b.x + a.y * b.y + a.z * b.z;
}

Vector3 crossProduct(const Vector3& a, const Vector3& b) {
    return Vector3(a.y * b.z - a.z * b.y,
                   a.z * b.x - a.x * b.z,
                   a.x * b.y - a.y * b.z);
}

Answer 1

Bingo! My view matrix was wrong. Notice how I was setting the last column all to y.z...

Here's my amended view matrix:

Maths::Matrix4 mat;
Maths::Vector3 z = Maths::normalize(target - position);
Maths::Vector3 x = Maths::normalize(Maths::crossProduct(z, up));
Maths::Vector3 y = Maths::crossProduct(x, z);

mat(0, 0) = x.x; mat(0, 1) = y.x; mat(0, 2) = -z.x;
mat(1, 0) = x.y; mat(1, 1) = y.y; mat(1, 2) = -z.y;
mat(2, 0) = x.z; mat(1, 2) = y.z; mat(2, 2) = -z.z;

mat(3, 0) = -Maths::dotProduct(x, position);
mat(3, 1) = -Maths::dotProduct(y, position);
mat(3, 2) = Maths::dotProduct(z, position);