static void
set_clip_plane (GLint plane_num,
const float *vertex_a,
const float *vertex_b)
{
#if defined (HAVE_COGL_GLES2) || defined (HAVE_COGL_GLES)
GLfloat plane[4];
#else
GLdouble plane[4];
#endif
GLfloat angle;
CoglHandle framebuffer = _cogl_get_framebuffer ();
CoglMatrixStack *modelview_stack =
_cogl_framebuffer_get_modelview_stack (framebuffer);
CoglMatrixStack *projection_stack =
_cogl_framebuffer_get_projection_stack (framebuffer);
CoglMatrix inverse_projection;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
_cogl_matrix_stack_get_inverse (projection_stack, &inverse_projection);
/* Calculate the angle between the axes and the line crossing the
two points */
angle = atan2f (vertex_b[1] - vertex_a[1],
vertex_b[0] - vertex_a[0]) * (180.0/G_PI);
_cogl_matrix_stack_push (modelview_stack);
/* Load the inverse of the projection matrix so we can specify the plane
* in screen coordinates */
_cogl_matrix_stack_set (modelview_stack, &inverse_projection);
/* Rotate about point a */
_cogl_matrix_stack_translate (modelview_stack,
vertex_a[0], vertex_a[1], vertex_a[2]);
/* Rotate the plane by the calculated angle so that it will connect
the two points */
_cogl_matrix_stack_rotate (modelview_stack, angle, 0.0f, 0.0f, 1.0f);
_cogl_matrix_stack_translate (modelview_stack,
-vertex_a[0], -vertex_a[1], -vertex_a[2]);
_cogl_matrix_stack_flush_to_gl (modelview_stack, COGL_MATRIX_MODELVIEW);
plane[0] = 0;
plane[1] = -1.0;
plane[2] = 0;
plane[3] = vertex_a[1];
#if defined (HAVE_COGL_GLES2) || defined (HAVE_COGL_GLES)
GE( glClipPlanef (plane_num, plane) );
#else
GE( glClipPlane (plane_num, plane) );
#endif
_cogl_matrix_stack_pop (modelview_stack);
}
static void
set_clip_plane (CoglFramebuffer *framebuffer,
GLint plane_num,
const float *vertex_a,
const float *vertex_b)
{
GLfloat planef[4];
double planed[4];
GLfloat angle;
CoglMatrixStack *modelview_stack =
_cogl_framebuffer_get_modelview_stack (framebuffer);
CoglMatrixStack *projection_stack =
_cogl_framebuffer_get_projection_stack (framebuffer);
CoglMatrix inverse_projection;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
_cogl_matrix_stack_get_inverse (projection_stack, &inverse_projection);
/* Calculate the angle between the axes and the line crossing the
two points */
angle = atan2f (vertex_b[1] - vertex_a[1],
vertex_b[0] - vertex_a[0]) * (180.0/G_PI);
_cogl_matrix_stack_push (modelview_stack);
/* Load the inverse of the projection matrix so we can specify the plane
* in screen coordinates */
_cogl_matrix_stack_set (modelview_stack, &inverse_projection);
/* Rotate about point a */
_cogl_matrix_stack_translate (modelview_stack,
vertex_a[0], vertex_a[1], vertex_a[2]);
/* Rotate the plane by the calculated angle so that it will connect
the two points */
_cogl_matrix_stack_rotate (modelview_stack, angle, 0.0f, 0.0f, 1.0f);
_cogl_matrix_stack_translate (modelview_stack,
-vertex_a[0], -vertex_a[1], -vertex_a[2]);
/* Clip planes can only be used when a fixed function backend is in
use so we know we can directly push this matrix to the builtin
state */
_cogl_matrix_entry_flush_to_gl_builtins (ctx,
modelview_stack->last_entry,
COGL_MATRIX_MODELVIEW,
framebuffer,
FALSE /* don't disable flip */);
planef[0] = 0;
planef[1] = -1.0;
planef[2] = 0;
planef[3] = vertex_a[1];
switch (ctx->driver)
{
default:
g_assert_not_reached ();
break;
case COGL_DRIVER_GLES1:
GE( ctx, glClipPlanef (plane_num, planef) );
break;
case COGL_DRIVER_GL:
planed[0] = planef[0];
planed[1] = planef[1];
planed[2] = planef[2];
planed[3] = planef[3];
GE( ctx, glClipPlane (plane_num, planed) );
break;
}
_cogl_matrix_stack_pop (modelview_stack);
}
