CODEWITHSUNDEEP
c++openglmatrixtransformation
Outurnate
Outurnate

Reputation: 96

glm lookAt and matrix transformation yielding odd behaviour

I am using glm::lookAt to get a matrix to transform the world by. This works fine, I can generate the matrix, the feed it into the shader, and it all works. What I now need to do is transform an arbitrary vector (ie 100,100,100,1) by the lookAt matrix. For some reason, I get garbage values

glm::mat4 model = glm::lookAt(glm::vec3(current_pos.x,
                                        current_pos.y, 
                                        current_pos.z),
                              glm::vec3(current_pos.x + dir.x,
                                        current_pos.y + dir.y, 
                                        current_pos.z + dir.z),
                              glm::vec3(up.x,up.y,up.z));
GLfloat fmodel[16] =
{
    model[0][0],
    model[0][1],
    model[0][2],
    model[0][3],

    model[1][0],
    model[1][1],
    model[1][2],
    model[1][3],

    model[2][0],
    model[2][1],
    model[2][2],
    model[2][3],

    model[3][0],
    model[3][1],
    model[3][2],
    model[3][3]
};

A printout of model's values: 0,1,2,3,0,1,2,3,0,1,2,3,0,1,2,3 I am calculating the point using model * vec4(x, y, z, 1)

The matrix is duplicated so I can pass it as a uniform. Both using the original matrix an constructing the matrix from the array yield identical results.

EDIT

Printing code is as follows:

for (unsigned i = 0; i < 16; ++i)
  printf("%d,", fmodel[i]);

This yields the output of 3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 no matter what my vectors are

Upvotes: 0

Views: 861

Answers (1)

Outurnate
Outurnate

Reputation: 96

Oddly, after using glm::value_ptr() rewriting large swathes of code, this is now working

Upvotes: 1

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