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我的問題與在使用OpenGL時從SFML獲取正確的鼠標座標有關。使用OpenGL在SFML中獲取正確的鼠標位置
基本上我正在Z軸上旋轉一個多邊形來查看當前的光標位置。
您還可以使用WASD鍵在屏幕上移動多邊形。
如果多邊形停留在屏幕的中心一切都很好，但當我將多邊形移動到屏幕的左上角時，會出現問題。
基本上它就像是獲取不正確的鼠標座標並超出實際鼠標光標的位置。
我用GL_LINES創建一種十字線來查看我的變量認爲鼠標光標在哪裏，並且它超出了實際位置。
爲了讓我使用這個鼠標的當前座標：
mouseX = Input.GetMouseX()-App.GetWidth()/2.f;
mouseY = Input.GetMouseY()-App.GetHeight()/2.f;
有誰知道我的問題可能是什麼？
爲了提供所有我可以得到的信息，下面是我的完整源代碼。 另外，如果我提供我的資源，那麼對於那些有興趣幫助的人，可以編譯它並查看我的意思，因爲我有點難以解釋。
抱歉它是如此凌亂 - 我是新來這個畢竟:)
#include <SFML/Window.hpp>
#include <iostream>
#include <cmath>
const float PI = 3.14159265f;
int main() {
// Angle of rotation for the polygon
float angle = 0.f;
sf::Window App(sf::VideoMode(800, 600, 32), "SFML OpenGL");
glClearDepth(1.f);
glClearColor(0.f, 0.f, 0.f, 0.f);
glEnable(GL_DEPTH_TEST);
glDepthMask(GL_TRUE);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(90.f, 1.2f, 1.f, 500.f);
// Current position of the polygon (used in glTranslatef)
GLfloat currentPosX = 0.f;
GLfloat currentPosY = 0.f;
// Current position of the mouse cursor
float mouseX = 0.f;
float mouseY = 0.f;
const sf::Input &Input = App.GetInput();
App.SetFramerateLimit(30);
while (App.IsOpened()) {
sf::Event Event;
while (App.GetEvent(Event)) {
if (Event.Type == sf::Event::Closed) {
App.Close();
}
if ((Event.Type == sf::Event::KeyPressed) && (Event.Key.Code == sf::Key::Escape)) {
App.Close();
}
if (Event.Type == sf::Event::Resized) {
glViewport(0, 0, Event.Size.Width, Event.Size.Height);
}
}
App.SetActive();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if(Input.IsKeyDown(sf::Key::W)) {
currentPosY += 3.f;
}
if(Input.IsKeyDown(sf::Key::S)) {
currentPosY -= 3.f;
}
if(Input.IsKeyDown(sf::Key::D)) {
currentPosX += 3.f;
}
if(Input.IsKeyDown(sf::Key::A)) {
currentPosX -= 3.f;
}
// Minus half of the screen width and height
// because the OpenGL origin is in the middle of the screen
mouseX = Input.GetMouseX()-App.GetWidth()/2.f;
mouseY = Input.GetMouseY()-App.GetHeight()/2.f;
// I don't know any better way to flip the Y axis so this is what I did
if(mouseY >= 0) {
mouseY = -(mouseY);
}
else {
mouseY = abs(mouseY);
}
// Calculate the angle which the polygon needs to rotate at
angle = atan2(mouseY - currentPosY, mouseX - currentPosX)*180/PI;
// Print variables to console to try and figure out what I'm doing wrong
std::cout << mouseX << "(" << currentPosX << ")" << ", " << mouseY << "(" << currentPosY << ")" << " - " << angle << std::endl;
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(currentPosX, currentPosY, -200.f);
glRotatef(angle, 0.f, 0.f, 1.f);
// Polygon
glBegin(GL_QUADS);
glVertex3f(-25.f, -25.f, -50.f);
glVertex3f(25.f, -25.f, -50.f);
glVertex3f(25.f, 25.f, -50.f);
glVertex3f(-25.f, 25.f, -50.f);
glEnd();
glLoadIdentity();
glTranslatef(currentPosX, currentPosY, -200.f);
// Axis on polygon
glBegin(GL_LINES);
glVertex3f(-70.f, 0.f, -50.f);
glVertex3f(70.f, 0.f, -50.f);
glVertex3f(0.f, -70.f, -50.f);
glVertex3f(0.f, 70.f, -50.f);
glEnd();
glLoadIdentity();
glTranslatef(currentPosX, currentPosY, -200.f);
glRotatef(angle, 0.f, 0.f, 1.f);
// Line to indicate the direction of the polygon
glBegin(GL_LINES);
glVertex3f(0.f, 0.f, -50.f);
glVertex3f(50.f, 0.f, -50.f);
glEnd();
glLoadIdentity();
glTranslatef(0.f, 0.f, -200.f);
// Screen axis
glBegin(GL_LINES);
glVertex3f(-400.f, 0.f, -60.f);
glVertex3f(400.f, 0.f, -60.f);
glVertex3f(0.f, 300.f, -60.f);
glVertex3f(0.f, -300.f, -60.f);
glEnd();
glLoadIdentity();
glTranslatef(mouseX, mouseY, -200.f);
// Cursor position
glBegin(GL_LINES);
glVertex3f(-10.f, 0.f, -60.f);
glVertex3f(10.f, 0.f, -60.f);
glVertex3f(0.f, 10.f, -60.f);
glVertex3f(0.f, -10.f, -60.f);
glEnd();
App.Display();
}
return 0;
}