On 10/08/2013 02:59 PM, Zack Rusin wrote:
As we're moving towards expanding the number of subpixel
bits and the width of the variables used in the computations
we need to make this code a bit more centralized.
Signed-off-by: Zack Rusin <za...@vmware.com>
---
src/gallium/drivers/llvmpipe/lp_rast.h | 9 +++++++++
src/gallium/drivers/llvmpipe/lp_setup.c | 14 +++++---------
src/gallium/drivers/llvmpipe/lp_setup_tri.c | 2 +-
3 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/src/gallium/drivers/llvmpipe/lp_rast.h
b/src/gallium/drivers/llvmpipe/lp_rast.h
index c57f2ea..43c598d 100644
--- a/src/gallium/drivers/llvmpipe/lp_rast.h
+++ b/src/gallium/drivers/llvmpipe/lp_rast.h
@@ -46,9 +46,18 @@ struct lp_scene;
struct lp_fence;
struct cmd_bin;
+#define FIXED_TYPE_WIDTH 32
/** For sub-pixel positioning */
#define FIXED_ORDER 4
#define FIXED_ONE (1<<FIXED_ORDER)
+/** Maximum length of an edge in a primitive in pixels.
+ * If the framebuffer is large we have to think about fixed-point
+ * integer overflow. Coordinates need ((FIXED_TYPE_WIDTH/2) - 1) bits
+ * to be able to fit product of two such coordinates inside
+ * FIXED_TYPE_WIDTH, any larger and we could overflow a
+ * FIXED_TYPE_WIDTH_-bit int.
+ */
+#define MAX_FIXED_LENGTH (1 << (((FIXED_TYPE_WIDTH/2) - 1) - FIXED_ORDER))
/* Rasterizer output size going to jit fs, width/height */
#define LP_RASTER_BLOCK_SIZE 4
diff --git a/src/gallium/drivers/llvmpipe/lp_setup.c
b/src/gallium/drivers/llvmpipe/lp_setup.c
index c8199b4..9b277d3 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup.c
+++ b/src/gallium/drivers/llvmpipe/lp_setup.c
@@ -1007,16 +1007,12 @@ try_update_scene_state( struct lp_setup_context *setup )
&setup->draw_regions[i]);
}
}
- /* If the framebuffer is large we have to think about fixed-point
- * integer overflow. For 2K by 2K images, coordinates need 15 bits
- * (2^11 + 4 subpixel bits). The product of two such numbers would
- * use 30 bits. Any larger and we could overflow a 32-bit int.
- *
- * To cope with this problem we check if triangles are large and
- * subdivide them if needed.
+ /*
+ * Subdivide triangles if the framebuffer is larger than the
+ * MAX_FIXED_LENGTH.
*/
- setup->subdivide_large_triangles = (setup->fb.width > 2048 ||
- setup->fb.height > 2048);
+ setup->subdivide_large_triangles = (setup->fb.width > MAX_FIXED_LENGTH ||
+ setup->fb.height > MAX_FIXED_LENGTH);
}
setup->dirty = 0;
diff --git a/src/gallium/drivers/llvmpipe/lp_setup_tri.c
b/src/gallium/drivers/llvmpipe/lp_setup_tri.c
index 051ffa0..9cc81e9 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup_tri.c
+++ b/src/gallium/drivers/llvmpipe/lp_setup_tri.c
@@ -988,7 +988,7 @@ check_subdivide_triangle(struct lp_setup_context *setup,
const float (*v2)[4],
triangle_func_t tri)
{
- const float maxLen = 2048.0f; /* longest permissible edge, in pixels */
+ const float maxLen = MAX_FIXED_LENGTH; /* longest permissible edge, in
pixels */
To avoid a lame MSVC warning, I think that line needs a cast:
const float maxLen = (float) MAX_FIXED_LENGTH; /* longest
permissible edge, in pixels */
float dx10, dy10, len10;
float dx21, dy21, len21;
float dx02, dy02, len02;
Reviewed-by: Brian Paul <bri...@vmware.com>
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