I am attempting to implement a perspective projection transformation using Haskell and OpenGL.
My vertices are set up as follows:
let vertices =
[ -0.3, 0.3, 0, -- Front Top Left 0
0.3, 0.3, 0, -- Front Top Right 1
0.3, -0.3, 0, -- Front Bottom Right 2
-0.3, -0.3, 0, -- Front Bottom Left 3
0.3, 0.3, 0, -- Back Top Left 4
0.3, 0, 0, -- Back Top Right 5
0.3, 0, 0, -- Back Bottom Right 6
0.3, 0.3, 0 -- Back Bottom Left 7 ]
and, using no transformation, or just the View transformation, everything appears as it should (a grey square).
The view transformation is
view = [cos ty * cos tz, cos tz * sin tx * sin ty - cos tx * sin tz, cos tx * cos tz * sin ty + sin tx * sin tz, -cx,
cos ty * sin tz, cos tx * cos tz + sin tx * sin ty * sin tz, -1 * cos tz * sin tx + cos tx * sin ty * sin tz, -cy,
-1 * sin ty, cos ty * sin tx, cos tx * cos ty, -cz,
0, 0, 0, 1]
where (cx, cy, cz) are the camera's position and (tx, ty, tz) are the cameras rotation about the axis in radian Euler angles.
The problems occurs when I apply the perspective transformation
perspective = [scale, 0, 0, 0,
0, scale, 0, 0,
0, 0, -1 * (far + near) / diff, -1,
0, 0, -2 * near * far / diff, 0]
where diff = far - near and scale = 1.0 / tan (fov / 2.0) and fov = 0.785.
My far and near planes are 10 and 0.01, respectively.
Once applied, using the following GLSL code, nothing appears (ie. only a black screen).
void main()
{
Color = color;
gl_Position = perspective * view * vec4(position, 1.0);
}
I have tried viewing the square from multiple different angles and positions, and with culling disabled.
What is wrong with my perspective projection matrix or the application of it?
