How can I transform a glm::vec3 by a glm::mat4

opengl transform glm-math
user1873578 picture user1873578 · Dec 3, 2012 · Viewed 18.2k times · Source

I want to transform a glm::vec3 (camera.target) by a glm::mat4 (camera.rotationMatrix). I try multiply this give me an error:error: no match for 'operator*' in 'originalTarget * ((Camera*)this)->Camera::rotationMatrix. I suppose that I can't multiply a vec3 * mat4. Does GLM some function to transform this? Other way to do the transform?

The code:

void Camera::Update(void)
{
// Aplicamos la rotacion sobre el target
glm::vec3 originalTarget = target;
glm::vec3 rotatedTarget = originalTarget * rotationMatrix;

// Aplicamos la rotacion sobre el Up
glm::vec3 originalUp = up;
glm::vec3 rotatedUp = originalUp * rotationMatrix;

// Establecemos las matrices de vista y proyeccion
view = lookAt(
position, //eye
rotatedTarget, //direction
rotatedUp //up
);
projection = perspective(
FOV,
(float) getParent()->getEngine()->GetCurrentWidth() / getParent()->getEngine()->GetCurrentWidth() ,
near_plane,
far_plane);
}

Answer

Xymostech picture Xymostech · Dec 3, 2012

You want to first convert your glm::vec3 into a glm::vec4 with the 4th element a 0, and then multiply them together.

glm::vec4 v(originalUp, 0);

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