trackball working with rectangle

git-svn-id: svn://anubis/misc/wfobj-view@30 bd8a9e45-a331-0410-811e-c64571078777

wfobj-view.cc

@@ -1,5 +1,6 @@
 
 /* Libraries we use */
+#include <SDL/SDL.h>
 #include <GL/gl.h>
 #include <GL/glu.h>
 
@@ -8,58 +9,113 @@
 #define HEIGHT 800
 #define TITLE "Josh's Wavefront Object Viewer"
 
-/* Some function prototypes */
-void	display(void);
-void	mouse(int button, int state, int x, int y);
-void	motion(int x, int y);
-
 /* Some global variables */
 float	rotationMatrix[16];
 int	startx, starty;
+bool dragging = false;
 
-/* The program's main entry point */
+void initgl(void)
-int	main(int argc, char *argv[])
 {
-	/* OpenGL initialization */
+	glClearColor(0.0, 0.0, 0.0, 0.0);
-	glShadeModel(GL_SMOOTH);
 	glEnable(GL_DEPTH_TEST);
+	glShadeModel(GL_SMOOTH);
 	glEnable(GL_LIGHTING);
 	glEnable(GL_LIGHT0);
-	float lpos[] = {0.0f, -6.0f, 0.0f, 1.0f};
+	float pos[] = {0.0, -1.0, 0.0, 0.0};
-	glLightfv(GL_LIGHT0, GL_POSITION, lpos);
+	glLightfv(GL_LIGHT0, GL_POSITION, pos);
 	glEnable(GL_CULL_FACE);
-	glClearColor(0, .3, 0.5, 1);
+	glViewport(0, 0, WIDTH, HEIGHT);
-	/* Initialize the default rotation matrix */
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	gluPerspective(60.0, (GLfloat)WIDTH/(GLfloat)WIDTH, 1.0, 30.0);
+	gluLookAt(0, -4.0, 0, 0, 0, 0, 0, 0, 1);
 	glMatrixMode(GL_MODELVIEW);
 	glLoadIdentity();
 	glGetFloatv(GL_MODELVIEW_MATRIX, rotationMatrix);
-	return 0;
 }
 
-/* This function is called to display the scene each refresh */
+void display(void)
-void	display(void)
 {
 	glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
 	glLoadIdentity();
 	glMultMatrixf(rotationMatrix);
+	glBegin(GL_QUADS);
+		glVertex3f(0.5, -0.5, 0.0);
+		glVertex3f(0.5, 0.5, 0.0);
+		glVertex3f(-0.5, 0.5, 0.0);
+		glVertex3f(-0.5, -0.5, 0.0);
+	glEnd();
+	SDL_GL_SwapBuffers();
 }
 
-/* handle mouse button press/release events */
+/* The program's main entry point */
-void	mouse(int button, int state, int x, int y)
+int	main(int argc, char * argv[])
 {
-	startx = x;
+	if (SDL_Init(SDL_INIT_VIDEO))
-	starty = y;
+	{
-}
+		printf("Failed to initialize SDL!\n");
-
+		return 1;
-/* handle mouse motion events */
+	}
-void	motion(int x, int y)
+
-{
+	atexit(SDL_Quit);
-	glLoadIdentity();
+
-	glRotatef(y-starty, 1, 0, 0);
+	SDL_Surface * screen;
-	glRotatef(x-startx, 0, 0, 1);
+	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
-	glMultMatrixf(rotationMatrix);
+	if (!(screen = SDL_SetVideoMode(WIDTH, HEIGHT, 32, SDL_OPENGL)))
-	glGetFloatv(GL_MODELVIEW_MATRIX, rotationMatrix);
+	{
-	startx=x;
+		printf("Failed to set video mode!\n");
-	starty=y;
+		SDL_Quit();
+		return 2;
+	}
+	SDL_WM_SetCaption(TITLE, TITLE);
+
+	initgl();
+	display();
+	SDL_Event event;
+	while (SDL_WaitEvent(&event))
+	{
+		if (event.type == SDL_QUIT)
+			break;
+		else if (event.type == SDL_KEYDOWN)
+		{
+			if (event.key.keysym.sym == SDLK_ESCAPE)
+				break;
+		}
+		else if (event.type == SDL_MOUSEBUTTONDOWN)
+		{
+			if (event.button.button == SDL_BUTTON_LEFT)
+			{
+				if (event.button.state == SDL_PRESSED)
+				{
+					dragging = true;
+					startx = event.button.x;
+					starty = event.button.y;
+				}
+			}
+		}
+		else if (event.type == SDL_MOUSEBUTTONUP)
+		{
+			if (event.button.button == SDL_BUTTON_LEFT)
+			{
+				dragging = false;
+			}
+		}
+		else if (event.type == SDL_MOUSEMOTION)
+		{
+			if (dragging)
+			{
+				glLoadIdentity();
+				glRotatef(event.motion.y - starty, 1, 0, 0);
+				glRotatef(event.motion.x - startx, 0, 0, 1);
+				glMultMatrixf(rotationMatrix);
+				glGetFloatv(GL_MODELVIEW_MATRIX, rotationMatrix);
+				startx = event.motion.x;
+				starty = event.motion.y;
+				display();
+			}
+		}
+	}
+
+	return 0;
 }