Finding world coord of mouse click
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I''m sure a recently saw some example code of how to use gluUnProject (I think) to get the world coordinates of a mouse click. I can''t quite remember where though. Anyway, I now need to do this. I tried doing it myself, but it doesn''t seem to be working quite right. The hard part is that I know the Z plane that the click should be in (I know the click will land on a ply in the z=1 plane), but I''m not sure how to use this to unproject. Anyway, does anyone know of some example code for this or something?
Thanks.
hi there, i have done this before on a game and this is how i did it...
bool CURSOR:ickCoords(float &coordX, float &coordZ){ glRenderMode(GL_SELECT); glInitNames(); glPushName(0); glPushMatrix(); glLoadIdentity(); glRotatef(-camera.rotX, 1.0f, 0.0f, 0.0f); glRotatef(-camera.rotY, 0.0f, 1.0f, 0.0f); glTranslatef(-camera.posX, -camera.posY, -camera.posZ); terrain.Render(SELECTION); glPopMatrix(); int hits=glRenderMode(GL_RENDER); if (hits > 0) { int choose = selectionBuffer[3]; // Make Our Selection The First Object int depth = selectionBuffer[1]; // Store How Far Away It Is for (int loop = 1; loop < hits; loop++) // Loop Through All The Detected Hits { if (selectionBuffer[loop*4+1] < (GLuint)depth) { choose = selectionBuffer[loop*4+3]; // Select The Closer Object depth = selectionBuffer[loop*4+1]; // Store How Far Away It Is } } int patchID=choose; float startX=(float)((patchID%MAPSIZE)*PATCHSIZE*MAPSCALE); float startY=(float)((patchID/MAPSIZE)*PATCHSIZE*MAPSCALE); hits=0; for(float loopY=0; loopY<((PATCHSIZE*MAPSCALE)/PICK_DETAIL); loopY+=(8.0f*PICK_DETAIL)) { for(float loopX=0; loopX<((PATCHSIZE*MAPSCALE)/PICK_DETAIL); loopX+=(8.0f*PICK_DETAIL)) { glRenderMode(GL_SELECT); glInitNames(); glPushName(0); glPushMatrix(); glLoadIdentity(); glRotatef(-camera.rotX, 1.0f, 0.0f, 0.0f); glRotatef(-camera.rotY, 0.0f, 1.0f, 0.0f); glTranslatef(-camera.posX, -camera.posY, -camera.posZ); terrain.RenderRT(startX+loopX, startY+loopY); glPopMatrix(); hits=glRenderMode(GL_RENDER); if (hits>0) { choose = selectionBuffer[3]; // Make Our Selection The First Object depth = selectionBuffer[1]; // Store How Far Away It Is for (int loop = 1; loop < hits; loop++) // Loop Through All The Detected Hits { if (selectionBuffer[loop*4+1] < (GLuint)depth) { choose = selectionBuffer[loop*4+3]; // Select The Closer Object depth = selectionBuffer[loop*4+1]; // Store How Far Away It Is } } coordX=(float)(startX+loopX+((choose%8)*PICK_DETAIL)); coordZ=(float)(startY+loopY+((choose/8)*PICK_DETAIL)); } } } return true; } return false;}i hope this helps
I ansver last time to when you ask... you can say if im not understand your question ^^
anyway you need to set up the pickmode first like this.
GLint viewport[4];
glGetIntegerv(GL_VIEWPORT, viewport);
glSelectBuffer(512, selectionBuffer);
glPushMatrix();
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
gluPickMatrix( (GLdouble) (x), (GLdouble) (y), (GLdouble)(s_system.width/50), (GLdouble)(s_system.height/50), viewport);
gluPerspective(45.0f, (GLfloat) (viewport[2]-viewport[0])/(GLfloat) (viewport[3]-viewport[1]), 0.1f, 100.0f);
glMatrixMode(GL_MODELVIEW);
GLint viewport[4];
glGetIntegerv(GL_VIEWPORT, viewport);
glSelectBuffer(512, selectionBuffer);
glPushMatrix();
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
gluPickMatrix( (GLdouble) (x), (GLdouble) (y), (GLdouble)(s_system.width/50), (GLdouble)(s_system.height/50), viewport);
gluPerspective(45.0f, (GLfloat) (viewport[2]-viewport[0])/(GLfloat) (viewport[3]-viewport[1]), 0.1f, 100.0f);
glMatrixMode(GL_MODELVIEW);
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