diff options
Diffstat (limited to 'src/gallium/drivers/llvmpipe/lp_setup_tri.c')
| -rw-r--r-- | src/gallium/drivers/llvmpipe/lp_setup_tri.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/gallium/drivers/llvmpipe/lp_setup_tri.c b/src/gallium/drivers/llvmpipe/lp_setup_tri.c index 45ac6a79ada..cf3d536eb1d 100644 --- a/src/gallium/drivers/llvmpipe/lp_setup_tri.c +++ b/src/gallium/drivers/llvmpipe/lp_setup_tri.c @@ -865,6 +865,166 @@ rotate_fixed_position_12( struct fixed_position* position ) } +typedef void (*triangle_func_t)(struct lp_setup_context *setup, + const float (*v0)[4], + const float (*v1)[4], + const float (*v2)[4]); + + +/** + * Subdivide this triangle by bisecting edge (v0, v1). + * \param pv the provoking vertex (must = v0 or v1 or v2) + */ +static void +subdiv_tri(struct lp_setup_context *setup, + const float (*v0)[4], + const float (*v1)[4], + const float (*v2)[4], + const float (*pv)[4], + triangle_func_t tri) +{ + unsigned n = setup->fs.current.variant->shader->info.base.num_inputs + 1; + const struct lp_shader_input *inputs = + setup->fs.current.variant->shader->inputs; + float vmid[PIPE_MAX_ATTRIBS][4]; + const float (*vm)[4] = (const float (*)[4]) vmid; + unsigned i; + float w0, w1, wm; + boolean flatshade = setup->fs.current.variant->key.flatshade; + + /* find position midpoint (attrib[0] = position) */ + vmid[0][0] = 0.5f * (v1[0][0] + v0[0][0]); + vmid[0][1] = 0.5f * (v1[0][1] + v0[0][1]); + vmid[0][2] = 0.5f * (v1[0][2] + v0[0][2]); + vmid[0][3] = 0.5f * (v1[0][3] + v0[0][3]); + + w0 = v0[0][3]; + w1 = v1[0][3]; + wm = vmid[0][3]; + + /* interpolate other attributes */ + for (i = 1; i < n; i++) { + if ((inputs[i - 1].interp == LP_INTERP_COLOR && flatshade) || + inputs[i - 1].interp == LP_INTERP_CONSTANT) { + /* copy the provoking vertex's attribute */ + vmid[i][0] = pv[i][0]; + vmid[i][1] = pv[i][1]; + vmid[i][2] = pv[i][2]; + vmid[i][3] = pv[i][3]; + } + else { + /* interpolate with perspective correction (for linear too) */ + vmid[i][0] = 0.5f * (v1[i][0] * w1 + v0[i][0] * w0) / wm; + vmid[i][1] = 0.5f * (v1[i][1] * w1 + v0[i][1] * w0) / wm; + vmid[i][2] = 0.5f * (v1[i][2] * w1 + v0[i][2] * w0) / wm; + vmid[i][3] = 0.5f * (v1[i][3] * w1 + v0[i][3] * w0) / wm; + } + } + + /* handling flat shading and first vs. last provoking vertex is a + * little tricky... + */ + if (pv == v0) { + if (setup->flatshade_first) { + /* first vertex must be v0 or vm */ + tri(setup, v0, vm, v2); + tri(setup, vm, v1, v2); + } + else { + /* last vertex must be v0 or vm */ + tri(setup, vm, v2, v0); + tri(setup, v1, v2, vm); + } + } + else if (pv == v1) { + if (setup->flatshade_first) { + tri(setup, vm, v2, v0); + tri(setup, v1, v2, vm); + } + else { + tri(setup, v2, v0, vm); + tri(setup, v2, vm, v1); + } + } + else { + if (setup->flatshade_first) { + tri(setup, v2, v0, vm); + tri(setup, v2, vm, v1); + } + else { + tri(setup, v0, vm, v2); + tri(setup, vm, v1, v2); + } + } +} + + +/** + * Check the lengths of the edges of the triangle. If any edge is too + * long, subdivide the longest edge and draw two sub-triangles. + * Note: this may be called recursively. + * \return TRUE if triangle was subdivided, FALSE otherwise + */ +static boolean +check_subdivide_triangle(struct lp_setup_context *setup, + const float (*v0)[4], + const float (*v1)[4], + const float (*v2)[4], + triangle_func_t tri) +{ + const float maxLen = 2048.0f; /* longest permissible edge, in pixels */ + float dx10, dy10, len10; + float dx21, dy21, len21; + float dx02, dy02, len02; + const float (*pv)[4] = setup->flatshade_first ? v0 : v2; + + /* compute lengths of triangle edges, squared */ + dx10 = v1[0][0] - v0[0][0]; + dy10 = v1[0][1] - v0[0][1]; + len10 = dx10 * dx10 + dy10 * dy10; + + dx21 = v2[0][0] - v1[0][0]; + dy21 = v2[0][1] - v1[0][1]; + len21 = dx21 * dx21 + dy21 * dy21; + + dx02 = v0[0][0] - v2[0][0]; + dy02 = v0[0][1] - v2[0][1]; + len02 = dx02 * dx02 + dy02 * dy02; + + /* Look for longest the edge that's longer than maxLen. If we find + * such an edge, split the triangle using the midpoint of that edge. + * Note: it's important to split the longest edge, not just any edge + * that's longer than maxLen. Otherwise, we can get into a degenerate + * situation and recurse indefinitely. + */ + if (len10 > maxLen * maxLen && + len10 >= len21 && + len10 >= len02) { + /* subdivide v0, v1 edge */ + subdiv_tri(setup, v0, v1, v2, pv, tri); + return TRUE; + } + + if (len21 > maxLen * maxLen && + len21 >= len10 && + len21 >= len02) { + /* subdivide v1, v2 edge */ + subdiv_tri(setup, v1, v2, v0, pv, tri); + return TRUE; + } + + if (len02 > maxLen * maxLen && + len02 >= len21 && + len02 >= len10) { + /* subdivide v2, v0 edge */ + subdiv_tri(setup, v2, v0, v1, pv, tri); + return TRUE; + } + + return FALSE; +} + + /** * Draw triangle if it's CW, cull otherwise. */ @@ -874,6 +1034,11 @@ static void triangle_cw( struct lp_setup_context *setup, const float (*v2)[4] ) { struct fixed_position position; + + if (setup->subdivide_large_triangles && + check_subdivide_triangle(setup, v0, v1, v2, triangle_cw)) + return; + calc_fixed_position(setup, &position, v0, v1, v2); if (position.area < 0) { @@ -894,6 +1059,11 @@ static void triangle_ccw( struct lp_setup_context *setup, const float (*v2)[4]) { struct fixed_position position; + + if (setup->subdivide_large_triangles && + check_subdivide_triangle(setup, v0, v1, v2, triangle_ccw)) + return; + calc_fixed_position(setup, &position, v0, v1, v2); if (position.area > 0) @@ -909,6 +1079,11 @@ static void triangle_both( struct lp_setup_context *setup, const float (*v2)[4] ) { struct fixed_position position; + + if (setup->subdivide_large_triangles && + check_subdivide_triangle(setup, v0, v1, v2, triangle_both)) + return; + calc_fixed_position(setup, &position, v0, v1, v2); if (0) { |