flythrough_camera
Single-header single-function C/C++ immediate-mode camera for your graphics demos
Just call flythrough_camera_update once per frame.
Simple Example
Below is a fully-functional example program that works under command prompt.
Create a new Visual Studio project, drop this file in it, and it should just work.
#define FLYTHROUGH_CAMERA_IMPLEMENTATION
#include "flythrough_camera.h"
#include <Windows.h>
#include <stdio.h>
int main()
{
printf("flythrough_camera test:\n");
printf("hold right click, then move the mouse and press WASD/space/left ctrl\n");
float pos[3] = { 0.0f, 0.0f, 0.0f };
float look[3] = { 0.0f, 0.0f, 1.0f };
const float up[3] = { 0.0f, 1.0f, 0.0f };
LARGE_INTEGER then, now, freq;
QueryPerformanceFrequency(&freq);
QueryPerformanceCounter(&then);
POINT oldcursor;
GetCursorPos(&oldcursor);
while (!GetAsyncKeyState(VK_ESCAPE))
{
QueryPerformanceCounter(&now);
float delta_time_sec = (float)(now.QuadPart - then.QuadPart) / freq.QuadPart;
POINT cursor;
GetCursorPos(&cursor);
// only move and rotate camera when right mouse button is pressed
float activated = GetAsyncKeyState(VK_RBUTTON) ? 1.0f : 0.0f;
float view[16];
flythrough_camera_update(
pos, look, up, view,
delta_time_sec,
100.0f * (GetAsyncKeyState(VK_LSHIFT) ? 2.0f : 1.0f) * activated,
0.5f * activated,
80.0f,
cursor.x - oldcursor.x, cursor.y - oldcursor.y,
GetAsyncKeyState('W'), GetAsyncKeyState('A'), GetAsyncKeyState('S'), GetAsyncKeyState('D'),
GetAsyncKeyState(VK_SPACE), GetAsyncKeyState(VK_LCONTROL),
FLYTHROUGH_CAMERA_LEFT_HANDED_BIT);
if (activated)
{
printf("\n");
printf("pos: %f, %f, %f\n", pos[0], pos[1], pos[2]);
printf("look: %f, %f, %f\n", look[0], look[1], look[2]);
printf("view: %f %f %f %f\n"
" %f %f %f %f\n"
" %f %f %f %f\n"
" %f %f %f %f\n",
view[0], view[1], view[2], view[3],
view[4], view[5], view[6], view[7],
view[8], view[9], view[10], view[11],
view[12], view[13], view[14], view[15]);
Sleep(100);
}
then = now;
oldcursor = cursor;
}
return 0;
}
OpenGL Example
Below is a fully-functional example program that works using OpenGL.
Create a new Visual Studio project, drop this file in it, and it should just work.
#define FLYTHROUGH_CAMERA_IMPLEMENTATION
#include "flythrough_camera.h"
#include <Windows.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <stdio.h>
#pragma comment(lib, "OpenGL32.lib")
#pragma comment(lib, "glu32.lib")
LRESULT CALLBACK MyWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CLOSE:
ExitProcess(0);
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
int CALLBACK WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
printf("flythrough_camera test:\n");
printf("hold right click, then move the mouse and press WASD/space/left ctrl\n");
WNDCLASSEX wc;
ZeroMemory(&wc, sizeof(wc));
wc.cbSize = sizeof(wc);
wc.style = CS_OWNDC;
wc.lpfnWndProc = MyWndProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)COLOR_BACKGROUND;
wc.lpszClassName = TEXT("WindowClass");
RegisterClassEx(&wc);
RECT wr = { 0, 0, 640, 480 };
AdjustWindowRect(&wr, 0, FALSE);
HWND hWnd = CreateWindowEx(
0, TEXT("WindowClass"),
TEXT("BasicGL"),
WS_OVERLAPPEDWINDOW,
0, 0, wr.right - wr.left, wr.bottom - wr.top,
0, 0, hInstance, 0);
PIXELFORMATDESCRIPTOR pfd;
ZeroMemory(&pfd, sizeof(pfd));
pfd.nSize = sizeof(pfd);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 32;
pfd.cDepthBits = 24;
pfd.cStencilBits = 8;
pfd.iLayerType = PFD_MAIN_PLANE;
HDC hDC = GetDC(hWnd);
int chosenPixelFormat = ChoosePixelFormat(hDC, &pfd);
SetPixelFormat(hDC, chosenPixelFormat, &pfd);
HGLRC hGLRC = wglCreateContext(hDC);
wglMakeCurrent(hDC, hGLRC);
ShowWindow(hWnd, SW_SHOWNORMAL);
float pos[3] = { 0.0f, 0.0f, 0.0f };
float look[3] = { 0.0f, 0.0f, 1.0f };
const float up[3] = { 0.0f, 1.0f, 0.0f };
LARGE_INTEGER then, now, freq;
QueryPerformanceFrequency(&freq);
QueryPerformanceCounter(&then);
POINT oldcursor;
GetCursorPos(&oldcursor);
while (!GetAsyncKeyState(VK_ESCAPE))
{
MSG msg;
while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
QueryPerformanceCounter(&now);
float delta_time_sec = (float)(now.QuadPart - then.QuadPart) / freq.QuadPart;
POINT cursor;
GetCursorPos(&cursor);
// only move and rotate camera when right mouse button is pressed
float activated = GetAsyncKeyState(VK_RBUTTON) ? 1.0f : 0.0f;
float view[16];
flythrough_camera_update(
pos, look, up, view,
delta_time_sec,
10.0f * (GetAsyncKeyState(VK_LSHIFT) ? 2.0f : 1.0f) * activated,
0.5f * activated,
80.0f,
cursor.x - oldcursor.x, cursor.y - oldcursor.y,
GetAsyncKeyState('W'), GetAsyncKeyState('A'), GetAsyncKeyState('S'), GetAsyncKeyState('D'),
GetAsyncKeyState(VK_SPACE), GetAsyncKeyState(VK_LCONTROL),
0);
if (activated)
{
printf("\n");
printf("pos: %f, %f, %f\n", pos[0], pos[1], pos[2]);
printf("look: %f, %f, %f\n", look[0], look[1], look[2]);
printf("view: %f %f %f %f\n"
" %f %f %f %f\n"
" %f %f %f %f\n"
" %f %f %f %f\n",
view[0], view[1], view[2], view[3],
view[4], view[5], view[6], view[7],
view[8], view[9], view[10], view[11],
view[12], view[13], view[14], view[15]);
}
glClear(GL_COLOR_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(70.0, (double)(wr.right - wr.left) / (wr.bottom - wr.top), 0.001, 100.0);
glMatrixMode(GL_MODELVIEW);
glLoadMatrixf(view);
glBegin(GL_TRIANGLES);
glColor3ub(255, 0, 0);
glVertex3f(-1.0f, -1.0f, 10.0f);
glColor3ub(0, 255, 0);
glVertex3f(1.0f, -1.0f, 10.0f);
glColor3ub(0, 0, 255);
glVertex3f(0.0f, 1.0f, 10.0f);
glEnd();
SwapBuffers(hDC);
then = now;
oldcursor = cursor;
}
return 0;
}