View Full Version : picking things with a mouse

06-30-2001, 04:02 PM
whats wrong with this code? - its mostly is nehe's

void SelectionL(void) // This Is Where Selection Is Done
GLuint buffer[512]; // Set Up A Selection Buffer
GLint hits; // The Number Of Objects That We Selected

// The Size Of The Viewport. [0] Is <x>, [1] Is <y>, [2] Is <length>, [3] Is <width>
GLint viewport[4];

// This Sets The Array <viewport> To The Size And Location Of The Screen Relative To The Window
glGetIntegerv(GL_VIEWPORT, viewport);
glSelectBuffer(1024, buffer); // Tell OpenGL To Use Our Array For Selection

// Puts OpenGL In Selection Mode. Nothing Will Be Drawn. Object ID's and Extents Are Stored In The Buffer.
(void) glRenderMode(GL_SELECT);

glInitNames(); // Initializes The Name Stack
glPushName(0); // Push 0 (At Least One Entry) Onto The Stack

glMatrixMode(GL_PROJECTION); // Selects The Projection Matrix
glPushMatrix(); // Push The Projection Matrix
glLoadIdentity(); // Resets The Matrix

// This Creates A Matrix That Will Zoom Up To A Small Portion Of The Screen, Where The Mouse Is.
gluPickMatrix((GLdouble) mouse_x, (GLdouble) (viewport[3]-mouse_y), 1.0f, 1.0f, viewport);

// Apply The Perspective Matrix
// gluPerspective(45.0f, (GLfloat) (viewport[2]-viewport[0])/(GLfloat) (viewport[3]-viewport[1]), 0.1f, 100.0f);
glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix

DrawMenuButtons(); // Render The Targets To The Selection Buffer

glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glPopMatrix(); // Pop The Projection Matrix
glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix
hits=glRenderMode(GL_RENDER); // Switch To Render Mode, Find Out How Many
// Objects Were Drawn Where The Mouse Was
if (hits > 0) // If There Were More Than 0 Hits
int choose = buffer[3]; // Make Our Selection The First Object
int depth = buffer[1]; // Store How Far Away It Is

for (int loop = 1; loop < hits; loop++) // Loop Through All The Detected Hits
// If This Object Is Closer To Us Than The One We Have Selected
if (buffer[loop*4+1] < GLuint(depth))
choose = buffer[loop*4+3]; // Select The Closer Object
depth = buffer[loop*4+1]; // Store How Far Away It Is

/*if (!object[choose].hit) // If The Object Hasn't Already Been Hit
object[choose].hit=TRUE; // Mark The Object As Being Hit
score+=1; // Increase Score
kills+=1; // Increase Level Kills
if (kills>level*5) // New Level Yet?
miss=0; // Misses Reset Back To Zero
kills=0; // Reset Level Kills
level+=1; // Increase Level
if (level>30) // Higher Than 30?
level=30; // Set Level To 30 (Are You A God?)

void DrawMenuButtons()


for (int loop1=0; loop1<=7; loop1++)
else glColor3f(1.0f,1.0f,1.0f);



glTexCoord2d(0,0); glVertex2d(60,loop1*70);
glTexCoord2d(1,0); glVertex2d(260,loop1*70);
glTexCoord2d(1,1); glVertex2d(260,loop1*70+76);
glTexCoord2d(0,1); glVertex2d(60,loop1*70+76);

[This message has been edited by bobertperry (edited 06-30-2001).]

[This message has been edited by bobertperry (edited 06-30-2001).]

06-30-2001, 07:21 PM
Never mind i figured it out.