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?
This was solved by transposing the view matrix.