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I'm trying to make a visual "simulation" of the solar system using OpenGL and am using this function to orbit a planet around the sun (in a circular orbit).
glm::vec3 application::orbit(glm::vec3 thisPlanet, glm::vec3 otherPlanet, float rotSpeed, const time &dt)
{
float radius = glm::distance(thisPlanet, otherPlanet);
float angle = acosf((thisPlanet.x - otherPlanet.x) / radius) - atanf(1.0f) * 4.0f;
angle += dt.as_seconds() * rotSpeed;
if (angle > 2 * atanf(1.0f) * 4.0f)
angle -= 2 * atanf(1.0f) * 4.0f;
float x = otherPlanet.x + cosf(angle) * radius;
float z = otherPlanet.z + sinf(angle) * radius;
return glm::vec3(x, thisPlanet.y, z);
}
The function is called every frame like this:
void application::tick(const time &dt)
{
if (m_keyboard.key_released(GLFW_KEY_ESCAPE)) {
m_running = false;
}
m_controller.update(m_keyboard, m_mouse, dt);
m_cube_rotation += dt.as_seconds();
m_mercury_position = orbit(m_mercury_position, m_sun_position, 2.0f, dt);
// glm::mat4 world = glm::translate(glm::mat4(1.0f), m_cube_position)
// * glm::rotate(glm::mat4(1.0f), m_cube_rotation, glm::normalize(glm::vec3(1.0f, 1.0f, -1.0f)));
glm::mat4 sun = glm::translate(glm::scale(glm::mat4(1.0f), glm::vec3(2.0f, 2.0f, 2.0f)), m_sun_position)
* glm::rotate(glm::mat4(1.0f), m_cube_rotation, glm::normalize(glm::vec3(1.0f, 1.0f, -1.0f)));
glm::mat4 mercury = glm::translate(glm::scale(glm::mat4(1.0f), glm::vec3(1.0f, 1.0f, 1.0f)), m_mercury_position)
* glm::rotate(glm::mat4(1.0f), m_cube_rotation, glm::normalize(glm::vec3(1.0f, 1.0f, -1.0f)));
//m_crate.set_transform(world);
m_sun.set_transform(sun);
m_mercury.set_transform(mercury);
const int frames_per_second = int(1.0f / dt.as_seconds());
const int frame_timing_ms = int(dt.as_milliseconds());
m_overlay.pre_frame(m_width, m_height);
m_overlay.push_line("FPS: %d (%dms)", frames_per_second, frame_timing_ms);
}
Why doesn't the planet move?
This is how I would construct the model matrix:
mat4 model_mat;
const vec3 n_forward = dir.x;
const vec3 n_up = vec3(0, 1, 0);
const vec3 n_left = dir.z;
// construct a basis and a translation
model_mat[0] = normalize(vec4(n_left, 0.0f));
model_mat[1] = normalize(vec4(n_forward, 0.0f));
model_mat[2] = normalize(vec4(n_up, 0.0f));
model_mat[3] = vec4(p, 1.0f);
The position (e.g. p) is given by the parametric circle equation p = r cos(t) + r sin(t), where t is the elapsed time and r is the circular orbit radius. Also see: https://www.mathopenref.com/coordparamcircle.html
Does this help at all?
I'm using a "Dymanic Batch Renderer System", and i have an "Object.cpp" that has a function, and when it's call it returns the data it needs for the Batch to render a "Quad" on screen (also i'm gonna mention that this is on a 3D space so the Z movement, Z scaling and the XY rotation exist).
And for the math calculations i'm using the GLM library.
The rendering works fine and the batch too, the problem is the movement. The rotation actually works the way i want it to work, but the movement is what i'm not satisfied because it moves in the "Local Space" of the object. Meaning that, for example, if i rotate an object inside a batch 90° on the Y Axis, the X movement becomes Z movement, and Z movement becomes X movement.
I've been trying to look for an answer and i couldn't find anything. I think the problem probably is from the "rotationMatrix" that allows the object to rotate correctly, but i don't know if there's an extra "function" i have to add to move the object in the "World Space" instead of the "Local Space", and if there is, i don't know what "function" can be.
Now i'm gonna put here the entire code of "Object.cpp" so you guys can see how it works.
Object::Object(glm::vec3 pos, glm::vec3 rot, glm::vec3 sca, int ObjId)
: translationMatrix(glm::mat4(0)), rotationMatrix(glm::mat4(0))
{
id = ObjId;
position = pos;
lastPosition = pos + glm::vec3(1.0f);
scale = sca;
rotation = rot;
lastRotation = rot + glm::vec3(1.0f);
}
glm::mat4 One(1.0f);
Vertex* Object::UpdateObject(Vertex* target)
{
if (lastPosition != position)
{
translationMatrix = glm::translate(glm::identity<glm::mat4>(), -position);
lastPosition = position;
}
if (lastRotation != rotation)
{
glm::mat4 rotMatrixTemp(1.0f);
rotMatrixTemp = glm::rotate(rotMatrixTemp, glm::radians(rotation.x), glm::vec3(1.0f, 0.0f, 0.0f));
rotMatrixTemp = glm::rotate(rotMatrixTemp, glm::radians(rotation.y), glm::vec3(0.0f, 1.0f, 0.0f));
rotMatrixTemp = glm::rotate(rotMatrixTemp, glm::radians(rotation.z + 180.0f), glm::vec3(0.0f, 0.0f, 1.0f));
rotationMatrix = -translationMatrix * rotMatrixTemp * translationMatrix;
lastRotation = rotation;
}
float x = 1.0f, y = 1.0f;
if (flipX)
x *= -1;
if (flipY)
y *= -1;
target->position = rotationMatrix * glm::vec4(position.x - 0.5f * scale.x, position.y + 0.5f * scale.y, position.z, 1.0f);
target->color = glm::vec4(1.0f, 1.0f, 1.0f, 1.0f);
target->texcoord = glm::vec2(0.0f, y);
target++;
target->position = rotationMatrix * glm::vec4(position.x - 0.5f * scale.x, position.y - 0.5f * scale.y, position.z, 1.0f);
target->color = glm::vec4(1.0f, 1.0f, 1.0f, 1.0f);
target->texcoord = glm::vec2(0.0f, 0.0f);
target++;
target->position = rotationMatrix * glm::vec4(position.x + 0.5f * scale.x, position.y - 0.5f * scale.y, position.z, 1.0f);
target->color = glm::vec4(1.0f, 1.0f, 1.0f, 1.0f);
target->texcoord = glm::vec2(x, 0.0f);
target++;
target->position = rotationMatrix * glm::vec4(position.x + 0.5f * scale.x, position.y + 0.5f * scale.y, position.z, 1.0f);
target->color = glm::vec4(1.0f, 1.0f, 1.0f, 1.0f);
target->texcoord = glm::vec2(x, y);
target++;
return target;
}
So, to recap, what i'm trying to accomplish is moving these objects in the "World Space" instead of the "Local Space" (while also, keeping the rotation system in the "Local Space", if possible. Because otherwise the object's center is always gonna be (0, 0, 0) instead of being its own position).
To position an object in the world with a given orientation, you usually apply the rotation first then the translation, unless you are indeed trying to rotate the objects about the origin after translating it out. So either check that, or make sure you have a good reason to do have the translationMatrix in
rotationMatrix = -translationMatrix * rotMatrixTemp * translationMatrix
Because it seems like you have translation logic both in and out of the if blocks
I'm trying to calculate tight ortho projection around the camera for better shadow mapping. I'm first calculating the camera frustum 8 points in world space using basic trigonometry using fov, position, right, forward, near, and far parameters of the camera as follows:
PerspectiveFrustum::PerspectiveFrustum(const Camera* camera)
{
float height = tanf(camera->GetFov() / 2.0f) * camera->GetNear();
float width = height * Screen::GetWidth() / Screen::GetHeight();
glm::vec3 nearTop = camera->GetUp() * camera->GetNear() * height;
glm::vec3 nearRight = camera->GetRight() * camera->GetNear() * width;
glm::vec3 nearCenter = camera->GetEye() + camera->GetForward() * camera->GetNear();
glm::vec3 farTop = camera->GetUp() * camera->GetFar() * height;
glm::vec3 farRight = camera->GetRight() * camera->GetFar() * width;
glm::vec3 farCenter = camera->GetEye() + camera->GetForward() * camera->GetFar();
m_RightNearBottom = nearCenter + nearRight - nearTop;
m_RightNearTop = nearCenter + nearRight + nearTop;
m_LeftNearBottom = nearCenter - nearRight - nearTop;
m_LeftNearTop = nearCenter - nearRight + nearTop;
m_RightFarBottom = farCenter + nearRight - nearTop;
m_RightFarTop = farCenter + nearRight + nearTop;
m_LeftFarBottom = farCenter - nearRight - nearTop;
m_LeftFarTop = farCenter - nearRight + nearTop;
}
Then I calculate the frustum in light view and calculating the min and max point in each axis to calculate the bounding box of the ortho projection as follows:
inline glm::mat4 GetView() const
{
return glm::lookAt(m_Position, glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
}
glm::mat4 DirectionalLight::GetProjection(const Camera& camera) const
{
PerspectiveFrustum frustum = camera.GetFrustum();
glm::mat4 lightView = GetView();
std::array<glm::vec3, 8> frustumToLightView
{
lightView * glm::vec4(frustum.m_RightNearBottom, 1.0f),
lightView * glm::vec4(frustum.m_RightNearTop, 1.0f),
lightView * glm::vec4(frustum.m_LeftNearBottom, 1.0f),
lightView * glm::vec4(frustum.m_LeftNearTop, 1.0f),
lightView * glm::vec4(frustum.m_RightFarBottom, 1.0f),
lightView * glm::vec4(frustum.m_RightFarTop, 1.0f),
lightView * glm::vec4(frustum.m_LeftFarBottom, 1.0f),
lightView * glm::vec4(frustum.m_LeftFarTop, 1.0f)
};
glm::vec3 min{ INFINITY, INFINITY, INFINITY };
glm::vec3 max{ -INFINITY, -INFINITY, -INFINITY };
for (unsigned int i = 0; i < frustumToLightView.size(); i++)
{
if (frustumToLightView[i].x < min.x)
min.x = frustumToLightView[i].x;
if (frustumToLightView[i].y < min.y)
min.y = frustumToLightView[i].y;
if (frustumToLightView[i].z < min.z)
min.z = frustumToLightView[i].z;
if (frustumToLightView[i].x > max.x)
max.x = frustumToLightView[i].x;
if (frustumToLightView[i].y > max.y)
max.y = frustumToLightView[i].y;
if (frustumToLightView[i].z > max.z)
max.z = frustumToLightView[i].z;
}
return glm::ortho(min.x, max.x, min.y, max.y, min.z, max.z);
}
Doing this gives me empty shadow map, so something clearly wrong and I haven't being doing this right. Can someone help me by telling me what I'm doing wrong and why?
EDIT:
As said my calculations of the frustum were wrong and I've changed them to the following:
PerspectiveFrustum::PerspectiveFrustum(const Camera* camera)
{
float nearHalfHeight = tanf(camera->GetFov() / 2.0f) * camera->GetNear();
float nearHalfWidth = nearHalfHeight * Screen::GetWidth() / Screen::GetHeight();
float farHalfHeight = tanf(camera->GetFov() / 2.0f) * camera->GetFar();
float farHalfWidth = farHalfHeight * Screen::GetWidth() / Screen::GetHeight();
glm::vec3 nearCenter = camera->GetEye() + camera->GetForward() * camera->GetNear();
glm::vec3 nearTop = camera->GetUp() * nearHalfHeight;
glm::vec3 nearRight = camera->GetRight() * nearHalfWidth;
glm::vec3 farCenter = camera->GetEye() + camera->GetForward() * camera->GetFar();
glm::vec3 farTop = camera->GetUp() * farHalfHeight;
glm::vec3 farRight = camera->GetRight() * farHalfWidth;
m_RightNearBottom = nearCenter + nearRight - nearTop;
m_RightNearTop = nearCenter + nearRight + nearTop;
m_LeftNearBottom = nearCenter - nearRight - nearTop;
m_LeftNearTop = nearCenter - nearRight + nearTop;
m_RightFarBottom = farCenter + farRight - farTop;
m_RightFarTop = farCenter + farRight + farTop;
m_LeftFarBottom = farCenter - farRight - farTop;
m_LeftFarTop = farCenter - farRight + farTop;
}
Also flipped the z coordinates when creating the ortho projection as follows:
return glm::ortho(min.x, max.x, min.y, max.y, -min.z, -max.z);
Yet still nothing renders to the depth map. Any ideas?
Here's captured results as you can see top left corner quad shows the shadow map which is completely wrong even drawing shadows on the objects themselves as a result as can be seen:
https://gfycat.com/brightwealthybass
(The smearing of the shadow map values is just an artifact of the gif compresser I used it doesn't really happen so there's no problem of me not clearing the z-buffer of the FBO)
EDIT2::
Ok few things GetFov() returned degrees and not radians.. changed it.
I Also try the transformation from NDC to world space with the following code:
glm::mat4 inverseProjectViewMatrix = glm::inverse(camera.GetProjection() * camera.GetView());
std::array<glm::vec4, 8> NDC =
{
glm::vec4{-1.0f, -1.0f, -1.0f, 1.0f},
glm::vec4{1.0f, -1.0f, -1.0f, 1.0f},
glm::vec4{-1.0f, 1.0f, -1.0f, 1.0f},
glm::vec4{1.0f, 1.0f, -1.0f, 1.0f},
glm::vec4{-1.0f, -1.0f, 1.0f, 1.0f},
glm::vec4{1.0f, -1.0f, 1.0f, 1.0f},
glm::vec4{-1.0f, 1.0f, 1.0f, 1.0f},
glm::vec4{1.0f, 1.0f, 1.0f, 1.0f},
};
for (size_t i = 0; i < NDC.size(); i++)
{
NDC[i] = inverseProjectViewMatrix * NDC[i];
NDC[i] /= NDC[i].w;
}
For the far coordinates of the frustum they're equal to my calculation of the frustum, but for the near corners they're off as if my calculation of the near corners is halved by 2 (for x and y only).
For example:
RIGHT TOP NEAR CORNER:
my calculation yields - {0.055, 0.041, 2.9}
inverse NDC yields - {0.11, 0.082, 2.8}
So I'm not sure where my calculation got wrong, maybe you could point out?
Even with the inversed NDC coordinates I tried to use them as following:
glm::mat4 DirectionalLight::GetProjection(const Camera& camera) const
{
glm::mat4 lightView = GetView();
glm::mat4 inverseProjectViewMatrix = glm::inverse(camera.GetProjection() * camera.GetView());
std::array<glm::vec4, 8> NDC =
{
glm::vec4{-1.0f, -1.0f, 0.0f, 1.0f},
glm::vec4{1.0f, -1.0f, 0.0f, 1.0f},
glm::vec4{-1.0f, 1.0f, 0.0f, 1.0f},
glm::vec4{1.0f, 1.0f, 0.0f, 1.0f},
glm::vec4{-1.0f, -1.0f, 1.0f, 1.0f},
glm::vec4{1.0f, -1.0f, 1.0f, 1.0f},
glm::vec4{-1.0f, 1.0f, 1.0f, 1.0f},
glm::vec4{1.0f, 1.0f, 1.0f, 1.0f},
};
for (size_t i = 0; i < NDC.size(); i++)
{
NDC[i] = lightView * inverseProjectViewMatrix * NDC[i];
NDC[i] /= NDC[i].w;
}
glm::vec3 min{ INFINITY, INFINITY, INFINITY };
glm::vec3 max{ -INFINITY, -INFINITY, -INFINITY };
for (unsigned int i = 0; i < NDC.size(); i++)
{
if (NDC[i].x < min.x)
min.x = NDC[i].x;
if (NDC[i].y < min.y)
min.y = NDC[i].y;
if (NDC[i].z < min.z)
min.z = NDC[i].z;
if (NDC[i].x > max.x)
max.x = NDC[i].x;
if (NDC[i].y > max.y)
max.y = NDC[i].y;
if (NDC[i].z > max.z)
max.z = NDC[i].z;
}
return glm::ortho(min.x, max.x, min.y, max.y, min.z, max.z);
}
And still got bad result:
https://gfycat.com/negativemalealtiplanochinchillamouse
Let's start with your frustum calculation here:
float height = tanf(camera->GetFov() / 2.0f) * camera->GetNear();
[...]
glm::vec3 nearTop = camera->GetUp() * camera->GetNear() * height;
[...]
glm::vec3 farTop = camera->GetUp() * camera->GetFar() * height;
That's one to many GetNear in your multiplications. Conceptually, you could height represent half of the frustum height at unit distance (I still would name it differently) without projecting it to the near plane, then the rest of your formulas make more sense.
However, the whole approach is doubtful to begin with. To get the frustum corners in world space, you can simply unproject all 8 vertices of the [-1,1]^3 NDC cube. Since you want to transform that into your light space, you can even combine it to a single matrix m = lightView * inverse(projection * view), just don't forget the perspective divide after the multiplying the NDC cube vertices.
return glm::ortho(min.x, max.x, min.y, max.y, min.z, max.z);
Standard GL conventions use a view space where the camera is looking into negative z direction, but the zNear and zFar parameters are interpreted as distances along the viewing directions, so the actual viewing volume will range from -zFar, -zNear in view space. You'll have to flip the signs of your z dimension to get the actual bounding box you're looking for.
I'm attempting to rotate a cube around an axis and it's definitely behaving incorrectly. I'm assuming the problem lies in my matrix rotation code as everything else seems to be working. I can translate the model correctly along the x, y or z axis, as well as scale. My camera view matrix is working as expected as well and so is my projection matrix. If I remove the view matrix and or the projection matrix implementations the problem remains.
If you wish to see what result I'm getting, it's the exact same output as the gif shown on this stackoverflow post: Rotating a cube in modern opengl... looks strange
The cube appears to fold in on itself while rotating, then returns to normal after a full rotation and seems to rotate fine for about 20 degrees until folding in on itself again and repeating. My issue is the same as that in the linked to article, however my matrix class is not the same, so my problem, though the same, seemingly has a different solution.
Here's my stripped matrix declaration with possibly relevant operators
math.h
typedef struct matrix4x4
{
//Elements stored in ROW MAJOR ORDER
GLfloat matrix[16];
void translate(Vector3f translation);
void rotateX(GLfloat angle);
void rotateY(GLfloat angle);
void rotateZ(GLfloat angle);
void rotate(Vector3f angles);
void scale(Vector3f scales);
void scale(GLfloat scale);
inline matrix4x4& operator*=(const matrix4x4& rhs)
{
this->matrix[0] = this->matrix[0] * rhs.matrix[0] + this->matrix[1] * rhs.matrix[4] + this->matrix[2] * rhs.matrix[8] + this->matrix[3] * rhs.matrix[12];
this->matrix[1] = this->matrix[0] * rhs.matrix[1] + this->matrix[1] * rhs.matrix[5] + this->matrix[2] * rhs.matrix[9] + this->matrix[3] * rhs.matrix[13];
this->matrix[2] = this->matrix[0] * rhs.matrix[2] + this->matrix[1] * rhs.matrix[6] + this->matrix[2] * rhs.matrix[10] + this->matrix[3] * rhs.matrix[14];
this->matrix[3] = this->matrix[0] * rhs.matrix[3] + this->matrix[1] * rhs.matrix[7] + this->matrix[2] * rhs.matrix[11] + this->matrix[3] * rhs.matrix[15];
this->matrix[4] = this->matrix[4] * rhs.matrix[0] + this->matrix[5] * rhs.matrix[4] + this->matrix[6] * rhs.matrix[8] + this->matrix[7] * rhs.matrix[12];
this->matrix[5] = this->matrix[4] * rhs.matrix[1] + this->matrix[5] * rhs.matrix[5] + this->matrix[6] * rhs.matrix[9] + this->matrix[7] * rhs.matrix[13];
this->matrix[6] = this->matrix[4] * rhs.matrix[2] + this->matrix[5] * rhs.matrix[6] + this->matrix[6] * rhs.matrix[10] + this->matrix[7] * rhs.matrix[14];
this->matrix[7] = this->matrix[4] * rhs.matrix[3] + this->matrix[5] * rhs.matrix[7] + this->matrix[6] * rhs.matrix[11] + this->matrix[7] * rhs.matrix[15];
this->matrix[8] = this->matrix[8] * rhs.matrix[0] + this->matrix[9] * rhs.matrix[4] + this->matrix[10] * rhs.matrix[8] + this->matrix[11] * rhs.matrix[12];
this->matrix[9] = this->matrix[8] * rhs.matrix[1] + this->matrix[9] * rhs.matrix[5] + this->matrix[10] * rhs.matrix[9] + this->matrix[11] * rhs.matrix[13];
this->matrix[10] = this->matrix[8] * rhs.matrix[2] + this->matrix[9] * rhs.matrix[6] + this->matrix[10] * rhs.matrix[10] + this->matrix[11] * rhs.matrix[14];
this->matrix[11] = this->matrix[8] * rhs.matrix[3] + this->matrix[9] * rhs.matrix[7] + this->matrix[10] * rhs.matrix[11] + this->matrix[11] * rhs.matrix[15];
this->matrix[12] = this->matrix[12] * rhs.matrix[0] + this->matrix[13] * rhs.matrix[4] + this->matrix[14] * rhs.matrix[8] + this->matrix[15] * rhs.matrix[12];
this->matrix[13] = this->matrix[12] * rhs.matrix[1] + this->matrix[13] * rhs.matrix[5] + this->matrix[14] * rhs.matrix[9] + this->matrix[15] * rhs.matrix[13];
this->matrix[14] = this->matrix[12] * rhs.matrix[2] + this->matrix[13] * rhs.matrix[6] + this->matrix[14] * rhs.matrix[10] + this->matrix[15] * rhs.matrix[14];
this->matrix[15] = this->matrix[12] * rhs.matrix[3] + this->matrix[13] * rhs.matrix[7] + this->matrix[14] * rhs.matrix[11] + this->matrix[15] * rhs.matrix[15];
return *this;
}
}matrix4x4;
matrix4x4 createTransformationMatrix(Vector3f translation, Vector3f rotation, Vector3f scale);
matrix4x4 createPerspectiveProjectionMatrix(GLfloat width, GLfloat height, GLfloat fov, GLfloat nearPlane, GLfloat farPlane);
matrix4x4 createViewMatrix(Vector3f cameraPosition, GLfloat cameraPitch, GLfloat cameraYaw, GLfloat cameraRoll);
and it's relevant implementations
math.cpp
matrix4x4::matrix4x4(GLfloat elements[])
{
//Elements stored in ROW MAJOR ORDER
for (unsigned int i = 0; i <= elementCount; i++)
{
matrix[i] = elements[i];
}
}
void matrix4x4::setIdentity()
{
std::fill(matrix, matrix + sizeof(matrix) / sizeof(GLfloat), 0.0f);
matrix[0] = 1;
matrix[5] = 1;
matrix[10] = 1;
matrix[15] = 1;
}
/*/////////////////////////////////////////////////////
math
/////////////////////////////////////////////////////*/
void matrix4x4::translate(Vector3f translation)
{
GLfloat transformElements[16] =
{
1.0f, 0.0f, 0.0f, translation.x,
0.0f, 1.0f, 0.0f, translation.y,
0.0f, 0.0f, 1.0f, translation.z,
0.0f, 0.0f, 0.0f, 1.0f
};
matrix4x4 transform = matrix4x4(transformElements);
*this *= transform;
}
void matrix4x4::rotateX(GLfloat angle)
{
angle = degreesToRadians(angle);
GLfloat transformElements[16] =
{
1.0f, 0.0f, 0.0f, 0.0f,
0.0f, std::cos(-angle), -std::sin(-angle), 0.0f,
0.0f, std::sin(-angle), std::cos(-angle), 0.0f,
0.0f, 0.0f, 0.0f, 1.0f
};
matrix4x4 transform = matrix4x4(transformElements);
*this *= transform;
}
void matrix4x4::rotateY(GLfloat angle)
{
angle = degreesToRadians(angle);
GLfloat transformElements[16] =
{
std::cos(-angle), 0.0f, std::sin(-angle), 0.0f,
0.0f, 1.0f, 0.0f, 0.0f,
-std::sin(-angle), 0.0f, std::cos(-angle), 0.0f,
0.0f, 0.0f, 0.0f, 1.0f
};
matrix4x4 transform = matrix4x4(transformElements);
*this *= transform;
}
void matrix4x4::rotateZ(GLfloat angle)
{
angle = degreesToRadians(angle);
GLfloat transformElements[16] =
{
std::cos(-angle), -std::sin(-angle), 0.0f, 0.0f,
std::sin(-angle), std::cos(-angle), 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f
};
matrix4x4 transform = matrix4x4(transformElements);
*this *= transform;
}
void matrix4x4::rotate(Vector3f angles)
{
matrix4x4 transform = matrix4x4();
transform.setIdentity();
transform.rotateX(angles.x);
transform.rotateY(angles.y);
transform.rotateZ(angles.z);
*this *= transform;
}
void matrix4x4::scale(Vector3f scales)
{
GLfloat transformElements[16] =
{
scales.x, 0.0f, 0.0f, 0.0f,
0.0f, scales.y, 0.0f, 0.0f,
0.0f, 0.0f, scales.z, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f
};
matrix4x4 transform = matrix4x4(transformElements);
*this *= transform;
}
matrix4x4 createTransformationMatrix(Vector3f translation, Vector3f rotation, Vector3f scale)
{
matrix4x4 transformationMatrix;
transformationMatrix.setIdentity();
//I've tried changing the order of these around, as well as only
//doing one operation (skipping translate and scale, or everything but a single axis rotation
transformationMatrix.translate(translation);
transformationMatrix.rotate(rotation);
transformationMatrix.scale(scale);
return transformationMatrix;
}
matrix4x4 createPerspectiveProjectionMatrix(GLfloat width, GLfloat height, GLfloat fov, GLfloat nearPlane, GLfloat farPlane)
{
matrix4x4 projectionMatrix;
projectionMatrix.setIdentity();
GLfloat aspectRatio = width / height;
projectionMatrix.matrix[0] = (1.0f / std::tan((degreesToRadians(fov)) / 2.0f) / aspectRatio);
projectionMatrix.matrix[5] = 1.0f / std::tan((degreesToRadians(fov)) / 2.0f);
projectionMatrix.matrix[10] = (farPlane + nearPlane) / (nearPlane - farPlane);
projectionMatrix.matrix[11] = (2.0f * farPlane * nearPlane) / (nearPlane - farPlane);
projectionMatrix.matrix[14] = -1.0f;
return projectionMatrix;
}
I know my matrix/vector implementations are quick and dirty, but I'm just trying to get something set up. I've got plans to make the math methods (scale, translate, etc) static methods that don't affect the contents of the matrix, but instead accept a matrix as input and return a new one... but that's not the issue right now.
Here's my vertex shader
#version 330 core
//declare inputs
in vec3 position;
in vec2 textureCoords;
//declare output
out vec2 pass_textureCoords;
//uniforms
uniform mat4 transformationMatrix;
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
void main(void)
{
//tell OpenGL where to render the vertex on screen
gl_Position = projectionMatrix * viewMatrix * transformationMatrix * vec4(position.x, position.y, position.z, 1.0);
pass_textureCoords = textureCoords;
}
My render method...
void Renderer::render(Entity entity, Shader* shader)
{
...
RawModel* rawModel = texturedModel->getRawModel();
glBindVertexArray(rawModel->getVaoID());
...
matrix4x4 transformationMatrix = createTransformationMatrix(entity.getPosition(), entity.getRotation(), entity.getScale());
shader->loadTransformationMatrix(transformationMatrix);
...
glDrawElements(GL_TRIANGLES, rawModel->getVertexCount(), GL_UNSIGNED_INT, 0);
...
}
And finally the relevant pieces from my main. The cube definitions and so on
//This is a simple cube
std::vector<GLfloat> vertices =
{
-0.5f,0.5f,-0.5f,
-0.5f,-0.5f,-0.5f,
0.5f,-0.5f,-0.5f,
0.5f,0.5f,-0.5f,
-0.5f,0.5f,0.5f,
-0.5f,-0.5f,0.5f,
0.5f,-0.5f,0.5f,
0.5f,0.5f,0.5f,
0.5f,0.5f,-0.5f,
0.5f,-0.5f,-0.5f,
0.5f,-0.5f,0.5f,
0.5f,0.5f,0.5f,
-0.5f,0.5f,-0.5f,
-0.5f,-0.5f,-0.5f,
-0.5f,-0.5f,0.5f,
-0.5f,0.5f,0.5f,
-0.5f,0.5f,0.5f,
-0.5f,0.5f,-0.5f,
0.5f,0.5f,-0.5f,
0.5f,0.5f,0.5f,
-0.5f,-0.5f,0.5f,
-0.5f,-0.5f,-0.5f,
0.5f,-0.5f,-0.5f,
0.5f,-0.5f,0.5f
};
std::vector<GLfloat> textureCoords =
{
...
};
std::vector<GLuint> indices =
{
0,1,3,
3,1,2,
4,5,7,
7,5,6,
8,9,11,
11,9,10,
12,13,15,
15,13,14,
16,17,19,
19,17,18,
20,21,23,
23,21,22
};
//parameters are (model, pos, rotation, scale)
Entity entity = Entity(&texturedModel, Vector3f(0.0f, 0.0f, -2.0f), Vector3f(0.0f, 0.0f, 0.0f), 1.0f);
//SHADER STUFF
Shader textureShader = Shader("uniformVarTextureShader");
textureShader.loadProjectionMatrix(display.getProjectionMatrix());
Camera cam;
//draw in wireframe mode
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
//glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
while (display.checkForClose() == 0)
{
glfwPollEvents();
//TO DO: update logic here
//entity.varyPosition(+0.005f, 0.0f, -0.002f); //this works, as does scaling and camera movement
//entity.varyRotation(0.25f, 0.18f, 0.0f);
entity.setYRotation(entity.getYRotation() + 0.25f); //any sort of rotation operation ends up with the strange behaivor
//rendering commands here
display.prepare();
textureShader.bind();
textureShader.loadViewMatrix(cam);
display.render(entity, &textureShader);
textureShader.stop();
display.swapBuffers();
}
So, to recap; I'm not having any issues with translating, scaling, "camera movement" and the projection matrix appears to work as well. Any time I attempt to rotate however, I get the exact same behavior as the linked to article above.
Final notes: I have depth testing enabled and clear the depth buffer each frame. I also pass GL_TRUE to transpose any matrix data I give to glUniformMatrix4fv. I've checked the locations of each of the uniforms and they are passing correctly; 0, 1 and 2 respectively. No -1.
I'm stumped, any help would be appreciated. I can post more code if need be, but I'm pretty sure this covers the entirety of where the problem most likely lies. Thanks again
The major issue is the matrix multipolication operation.
Since you manipulate the matrix (you read from the matrix and you write to it), are some elements already manipulated, before you read it.
e.g. In the first line this->matrix[0] is written to
this->matrix[0] = this->matrix[0] * rhs.matrix[0] + this->matrix[1] * rhs.matrix[4] + this->matrix[2] * rhs.matrix[8] + this->matrix[3] * rhs.matrix[12];
and in the second line this->matrix[0] is read again:
this->matrix[1] = this->matrix[0] * rhs.matrix[1] + this->matrix[1] * rhs.matrix[5] + this->matrix[2] * rhs.matrix[9] + this->matrix[3] * rhs.matrix[13];
Copy the matrix array to a local variable, to solve the issue:
matrix4x4& operator*=(const matrix4x4& rhs)
{
matrix4x4 act( this->matrix );
this->matrix[0] = act.matrix[0] * rhs.matrix[0] + act.matrix[1] * rhs.matrix[4] + act.matrix[2] * rhs.matrix[8] + act.matrix[3] * rhs.matrix[12];
this->matrix[1] = act.matrix[0] * rhs.matrix[1] + act.matrix[1] * rhs.matrix[5] + act.matrix[2] * rhs.matrix[9] + act.matrix[3] * rhs.matrix[13];
....
return *this;
}
By the way, since you multiply a vector to the matrix from the right, in the shader
gl_Position = projectionMatrix * viewMatrix * transformationMatrix * vec4(position.x, position.y, position.z, 1.0);
the matrix has to be initilized in column major order:
mat4 m44 = mat4(
vec4( Xx, Xy, Xz, 0.0),
vec4( Yx, Xy, Yz, 0.0),
vec4( Zx Zy Zz, 0.0),
vec4( Tx, Ty, Tz, 1.0) );
Note your matrices are initialized in row major order e.g. matrix4x4::translate:
GLfloat transformElements[16] =
{
1.0f, 0.0f, 0.0f, translation.x,
0.0f, 1.0f, 0.0f, translation.y,
0.0f, 0.0f, 1.0f, translation.z,
0.0f, 0.0f, 0.0f, 1.0f
};
So you have to transpose the matrix when you set it to the uniform glUniformMatrix4fv:
glUniformMatrix4fv( ..., ..., GL_TRUE, ... );
float FoV = initialFoV - 5;
//(*it)->getParent()->getPosition() + (*it)->getOrientationQuat() * (*it)->getPosition();
glm::vec3 lookAt = carPosition;
glm::vec3 temp;
temp.x = spaceShip->orientation.y;
temp.y = spaceShip->orientation.x;
temp.z = spaceShip->orientation.z;
glm::vec3 cameraposition = carPosition + glm::quat(temp) * position;
ProjectionMatrix = glm::perspective(FoV, 4.0f / 3.0f, 0.1f, 100.0f);
ViewMatrix = glm::lookAt(
cameraposition, // Camera is here
lookAt, // and looks here : at the same position, plus "direction"
vec3(0, 1, 0) // Head is up (set to 0,-1,0 to look upside-down)
);
As you can see we build a third person camera, this camera is chasing our airplane. But when our airplane makes a looping, the camera will flip halfway through. So everything is upside down. How can we make sure the camera won't flip?
We fixed it by calculating the up instead of setting it.
glm::vec3 cameraposition = carPosition + glm::quat(temp) * position;
ProjectionMatrix = glm::perspective(FoV, 4.0f / 3.0f, 0.1f, 100.0f);
glm::mat4 RotationMatrix = eulerAngleYXZ(carDirection.x, carDirection.y, carDirection.z);
glm::vec4 up = RotationMatrix * glm::vec4(0,1,0,0);
glm::vec3 up3(up);
ViewMatrix = glm::lookAt(
cameraposition, // Camera is here
lookAt, // and looks here : at the same position, plus "direction"
up3 // Head is up (set to 0,-1,0 to look upside-down)
);