Picking: not working properly

[psychopath]

Ugh. I can't seem to get anything to work correctly lately.

Iv'e attempted to add mouse object picking, aided by an example from the OGL superbible (found by searching these forums). However, no matter where I click, it reads that I clicked the highest name ID (ex, if I have 3 objects, it always says I clicked object 3).

on rendering:

void prefab::renderprefabs()
{
	for(int i=0; i<num_prefabs; i++)
	{
		//if(!_ceFrustum.CubeInFrustum(prefabP[i].pos.x, prefabP[i].pos.y, prefabP[i].pos.z, 1.0f))
		//{
		//i++; }
		
		if(prefabP[i].type==0)
		{
			glPushMatrix();
			glLoadName(i+1);
			glMultMatrixf(&prefabP[i].matrix[0][0]);
			drawsolidcube(&prefabP[i],1,1);
			glPopMatrix();
		}
	}
}

picking code:

void processclicks(GLuint id)
{
	if(id==0)
		printf("miss\n");
	else if(id>0)
		printf("hit %d\n", id);
}

#define BUFFER_LENGTH 64
void ProcessSelection(int xPos, int yPos)
	{
	// Space for selection buffer
	GLuint selectBuff[BUFFER_LENGTH];

	// Hit counter and viewport storeage
	GLint hits, viewport[4];

	// Setup selection buffer
	glSelectBuffer(BUFFER_LENGTH, selectBuff);
	
	// Get the viewport
	glGetIntegerv(GL_VIEWPORT, viewport);

	// Switch to projection and save the matrix
	glMatrixMode(GL_PROJECTION);
	glPushMatrix();

	// Change render mode
	glRenderMode(GL_SELECT);

	// Establish new clipping volume to be unit cube around
	// mouse cursor point (xPos, yPos) and extending two pixels
	// in the vertical and horzontal direction
	glLoadIdentity();
	gluPickMatrix(xPos, viewport[3] - yPos, 2,2, viewport);

	// Apply perspective matrix 
	gluPerspective(50.0f, fAspect, 0.01, -1.0);

	// Draw the scene
	display();

	// Collect the hits
	hits = glRenderMode(GL_RENDER);

	// If a single hit occured, display the info.
	if(hits == 1)
		processclicks(selectBuff[3]);

	// Restore the projection matrix
	glMatrixMode(GL_PROJECTION);
	glPopMatrix();

	// Go back to modelview for normal rendering
	glMatrixMode(GL_MODELVIEW);
}

void mouse(int button, int state, int x, int y)
{
	if(button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
		ProcessSelection(x, y);
}

and before drawing I have

glInitNames();
glPushName(0);

The only lead I have to this, is that i'm probably just not doing it right ;p.

thanx
-psychopath

[skorman00]

void processclicks(GLuint id)
{
	if(id==0)
		printf("miss\n");
	else if(id>0)
		printf("hit %d\n", id);
}
.
.
.
	if(hits == 1)
		processclicks(selectBuff[3]);

1) I'm not sure what glSelectBuffer does, but it seems to me you're only testing the last object
2)processclicks should be doing more than checking the value if id. I'm not familiar with the glu libs, but I'm guessing what you want to do is multiply your mouse coords by the matrix you get from that ever so sexy looking gluPickMatrix function.