diff options
Diffstat (limited to 'src/gallium/auxiliary/util/u_prim.h')
-rw-r--r-- | src/gallium/auxiliary/util/u_prim.h | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/util/u_prim.h b/src/gallium/auxiliary/util/u_prim.h index 64390e1385..606b9b5c6b 100644 --- a/src/gallium/auxiliary/util/u_prim.h +++ b/src/gallium/auxiliary/util/u_prim.h @@ -169,6 +169,52 @@ u_vertices_per_prim(int primitive) } } +/** + * Returns the number of decomposed primitives for the given + * vertex count. + * Geometry shader is invoked once for each triangle in + * triangle strip, triangle fans and triangles and once + * for each line in line strip, line loop, lines. + */ +static INLINE unsigned +u_gs_prims_for_vertices(int primitive, int vertices) +{ + switch(primitive) { + case PIPE_PRIM_POINTS: + return vertices; + case PIPE_PRIM_LINES: + return vertices / 2; + case PIPE_PRIM_LINE_LOOP: + return vertices; + case PIPE_PRIM_LINE_STRIP: + return vertices - 1; + case PIPE_PRIM_TRIANGLES: + return vertices / 3; + case PIPE_PRIM_TRIANGLE_STRIP: + return vertices - 2; + case PIPE_PRIM_TRIANGLE_FAN: + return vertices - 2; + case PIPE_PRIM_LINES_ADJACENCY: + return vertices / 2; + case PIPE_PRIM_LINE_STRIP_ADJACENCY: + return vertices - 1; + case PIPE_PRIM_TRIANGLES_ADJACENCY: + return vertices / 3; + case PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY: + return vertices - 2; + + /* following primitives should never be used + * with geometry shaders abd their size is + * undefined */ + case PIPE_PRIM_POLYGON: + case PIPE_PRIM_QUADS: + case PIPE_PRIM_QUAD_STRIP: + default: + debug_printf("Unrecognized geometry shader primitive"); + return 3; + } +} + const char *u_prim_name( unsigned pipe_prim ); #endif |