+void update_monitor_vertices(CompositedScreen *screen, CompositedMonitor *monitor)
+{
+ unsigned t;
+ unsigned data_size;
+ float *vertex_data;
+ unsigned short *index_data;
+ unsigned x, y;
+ unsigned i;
+
+ t = monitor->tessellation;
+
+ data_size = (t+1)*(t+1)*4*sizeof(float);
+ vertex_data = (float *)malloc(data_size);
+ for(y=0; y<=t; ++y)
+ for(x=0; x<=t; ++x)
+ {
+ float xf, yf;
+ float *v;
+
+ xf = (float)x/t;
+ yf = (float)y/t;
+ v = vertex_data+(y*(t+1)+x)*4;
+ v[0] = xf;
+ v[1] = yf;
+ v[2] = (monitor->x+xf*monitor->width)/screen->width;
+ v[3] = (monitor->y+yf*monitor->height)/screen->height;
+ }
+ glBindBuffer(GL_ARRAY_BUFFER, monitor->vertex_buffer);
+ glBufferData(GL_ARRAY_BUFFER, data_size, vertex_data, GL_STATIC_DRAW);
+ glBindBuffer(GL_ARRAY_BUFFER, 0);
+ free(vertex_data);
+
+ monitor->nelements = t*((t+1)*2+1)-1;
+ data_size = monitor->nelements*sizeof(unsigned short);
+ index_data = (unsigned short *)malloc(data_size);
+ i = 0;
+ for(y=0; y<t; ++y)
+ {
+ if(y>0)
+ index_data[i++] = 0xFFFF;
+ for(x=0; x<=t; ++x)
+ {
+ index_data[i++] = (y+1)*(t+1)+x;
+ index_data[i++] = y*(t+1)+x;
+ }
+ }
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, monitor->index_buffer);
+ glBufferData(GL_ELEMENT_ARRAY_BUFFER, data_size, index_data, GL_STATIC_DRAW);
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+ free(index_data);
+}
+
+int initialize_monitor(Compositor *compositor, CompositedScreen *screen, CompositedMonitor *monitor, XRRScreenResources *xrr_res, unsigned index)
+{
+ XRROutputInfo *output;
+ XRRCrtcInfo *crtc;
+ unsigned buffers[2];
+ unsigned stride;
+
+ output = XRRGetOutputInfo(compositor->display, xrr_res, xrr_res->outputs[index]);
+ monitor->enabled = !!output->crtc;
+ if(!monitor->enabled)
+ {
+ XRRFreeOutputInfo(output);
+ return 1;
+ }
+
+ crtc = XRRGetCrtcInfo(compositor->display, xrr_res, output->crtc);
+ monitor->x = crtc->x;
+ monitor->y = crtc->y;
+ monitor->width = crtc->width;
+ monitor->height = crtc->height;
+ XRRFreeCrtcInfo(crtc);
+ XRRFreeOutputInfo(output);
+
+ glGenBuffers(2, buffers);
+ monitor->vertex_buffer = buffers[0];
+ monitor->index_buffer = buffers[1];
+
+ monitor->tessellation = 20;
+ update_monitor_vertices(screen, monitor);
+ stride = 4*sizeof(float);
+
+ glGenVertexArrays(1, &monitor->vertex_array);
+ glBindVertexArray(monitor->vertex_array);
+ glBindBuffer(GL_ARRAY_BUFFER, monitor->vertex_buffer);
+ glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, stride, NULL);
+ glEnableVertexAttribArray(0);
+ glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, stride, (void *)(2*sizeof(float)));
+ glEnableVertexAttribArray(1);
+ glBindBuffer(GL_ARRAY_BUFFER, 0);
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, monitor->index_buffer);
+ glBindVertexArray(0);
+
+ return 1;
+}
+