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); }