Mesa (master): llvmpipe: add plumbing for ARB_depth_clamp
Jose Fonseca
jrfonseca at kemper.freedesktop.org
Wed Dec 11 18:38:58 UTC 2013
Module: Mesa
Branch: master
Commit: e84a1ab3c400f819408a7ebe01c2325cd59d94d3
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=e84a1ab3c400f819408a7ebe01c2325cd59d94d3
Author: Matthew McClure <mcclurem at vmware.com>
Date: Tue Dec 10 13:10:03 2013 -0800
llvmpipe: add plumbing for ARB_depth_clamp
With this patch llvmpipe will adhere to the ARB_depth_clamp enabled state when
clamping the fragment's zw value. To support this, the variant key now includes
the depth_clamp state. key->depth_clamp is derived from pipe_rasterizer_state's
(depth_clip == 0), thus depth clamp is only enabled when depth clip is disabled.
Reviewed-by: Roland Scheidegger <sroland at vmware.com>
Reviewed-by: José Fonseca <jfonseca at vmware.com>
---
src/gallium/drivers/llvmpipe/lp_setup.c | 11 +++-
src/gallium/drivers/llvmpipe/lp_state_fs.c | 83 +++++++++++++++++-----------
src/gallium/drivers/llvmpipe/lp_state_fs.h | 1 +
src/gallium/include/pipe/p_state.h | 2 +
4 files changed, 62 insertions(+), 35 deletions(-)
diff --git a/src/gallium/drivers/llvmpipe/lp_setup.c b/src/gallium/drivers/llvmpipe/lp_setup.c
index 31aaf96..49962af 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup.c
+++ b/src/gallium/drivers/llvmpipe/lp_setup.c
@@ -656,6 +656,7 @@ lp_setup_set_viewports(struct lp_setup_context *setup,
unsigned num_viewports,
const struct pipe_viewport_state *viewports)
{
+ struct llvmpipe_context *lp = llvmpipe_context(setup->pipe);
unsigned i;
LP_DBG(DEBUG_SETUP, "%s\n", __FUNCTION__);
@@ -670,8 +671,14 @@ lp_setup_set_viewports(struct lp_setup_context *setup,
float min_depth;
float max_depth;
- min_depth = viewports[i].translate[2];
- max_depth = viewports[i].translate[2] + viewports[i].scale[2];
+ if (lp->rasterizer->clip_halfz == 0) {
+ float half_depth = viewports[i].scale[2];
+ min_depth = viewports[i].translate[2] - half_depth;
+ max_depth = min_depth + half_depth * 2.0f;
+ } else {
+ min_depth = viewports[i].translate[2];
+ max_depth = min_depth + viewports[i].scale[2];
+ }
if (setup->viewports[i].min_depth != min_depth ||
setup->viewports[i].max_depth != max_depth) {
diff --git a/src/gallium/drivers/llvmpipe/lp_state_fs.c b/src/gallium/drivers/llvmpipe/lp_state_fs.c
index 93c24f6..2118c1a 100644
--- a/src/gallium/drivers/llvmpipe/lp_state_fs.c
+++ b/src/gallium/drivers/llvmpipe/lp_state_fs.c
@@ -445,47 +445,52 @@ generate_fs_loop(struct gallivm_state *gallivm,
0);
if (pos0 != -1 && outputs[pos0][2]) {
- LLVMValueRef viewport, min_depth, max_depth;
- LLVMValueRef viewport_index;
- struct lp_build_context f32_bld;
-
- assert(type.floating);
- lp_build_context_init(&f32_bld, gallivm, type);
+ z = LLVMBuildLoad(builder, outputs[pos0][2], "output.z");
/*
- * Assumes clamping of the viewport index will occur in setup/gs. Value
- * is passed through the rasterization stage via lp_rast_shader_inputs.
- *
- * See: draw_clamp_viewport_idx and lp_clamp_viewport_idx for clamping
- * semantics.
+ * Clamp according to ARB_depth_clamp semantics.
*/
- viewport_index = lp_jit_thread_data_raster_state_viewport_index(gallivm,
- thread_data_ptr);
+ if (key->depth_clamp) {
+ LLVMValueRef viewport, min_depth, max_depth;
+ LLVMValueRef viewport_index;
+ struct lp_build_context f32_bld;
- /*
- * Load the min and max depth from the lp_jit_context.viewports
- * array of lp_jit_viewport structures.
- */
- viewport = lp_llvm_viewport(context_ptr, gallivm, viewport_index);
+ assert(type.floating);
+ lp_build_context_init(&f32_bld, gallivm, type);
- /* viewports[viewport_index].min_depth */
- min_depth = LLVMBuildExtractElement(builder, viewport,
- lp_build_const_int32(gallivm, LP_JIT_VIEWPORT_MIN_DEPTH),
- "");
- min_depth = lp_build_broadcast_scalar(&f32_bld, min_depth);
+ /*
+ * Assumes clamping of the viewport index will occur in setup/gs. Value
+ * is passed through the rasterization stage via lp_rast_shader_inputs.
+ *
+ * See: draw_clamp_viewport_idx and lp_clamp_viewport_idx for clamping
+ * semantics.
+ */
+ viewport_index = lp_jit_thread_data_raster_state_viewport_index(gallivm,
+ thread_data_ptr);
- /* viewports[viewport_index].max_depth */
- max_depth = LLVMBuildExtractElement(builder, viewport,
- lp_build_const_int32(gallivm, LP_JIT_VIEWPORT_MAX_DEPTH),
- "");
- max_depth = lp_build_broadcast_scalar(&f32_bld, max_depth);
+ /*
+ * Load the min and max depth from the lp_jit_context.viewports
+ * array of lp_jit_viewport structures.
+ */
+ viewport = lp_llvm_viewport(context_ptr, gallivm, viewport_index);
- z = LLVMBuildLoad(builder, outputs[pos0][2], "output.z");
+ /* viewports[viewport_index].min_depth */
+ min_depth = LLVMBuildExtractElement(builder, viewport,
+ lp_build_const_int32(gallivm, LP_JIT_VIEWPORT_MIN_DEPTH),
+ "");
+ min_depth = lp_build_broadcast_scalar(&f32_bld, min_depth);
- /*
- * Clamp to the min and max depth values for the given viewport.
- */
- z = lp_build_clamp(&f32_bld, z, min_depth, max_depth);
+ /* viewports[viewport_index].max_depth */
+ max_depth = LLVMBuildExtractElement(builder, viewport,
+ lp_build_const_int32(gallivm, LP_JIT_VIEWPORT_MAX_DEPTH),
+ "");
+ max_depth = lp_build_broadcast_scalar(&f32_bld, max_depth);
+
+ /*
+ * Clamp to the min and max depth values for the given viewport.
+ */
+ z = lp_build_clamp(&f32_bld, z, min_depth, max_depth);
+ }
}
lp_build_depth_stencil_load_swizzled(gallivm, type,
@@ -2860,6 +2865,18 @@ make_variant_key(struct llvmpipe_context *lp,
}
}
+ /*
+ * Propagate the depth clamp setting from the rasterizer state.
+ * depth_clip == 0 implies depth clamping is enabled.
+ *
+ * When clip_halfz is enabled, then always clamp the depth values.
+ */
+ if (lp->rasterizer->clip_halfz) {
+ key->depth_clamp = 1;
+ } else {
+ key->depth_clamp = (lp->rasterizer->depth_clip == 0) ? 1 : 0;
+ }
+
/* alpha test only applies if render buffer 0 is non-integer (or does not exist) */
if (!lp->framebuffer.nr_cbufs ||
!util_format_is_pure_integer(lp->framebuffer.cbufs[0]->format)) {
diff --git a/src/gallium/drivers/llvmpipe/lp_state_fs.h b/src/gallium/drivers/llvmpipe/lp_state_fs.h
index aac4526..2ddd851 100644
--- a/src/gallium/drivers/llvmpipe/lp_state_fs.h
+++ b/src/gallium/drivers/llvmpipe/lp_state_fs.h
@@ -76,6 +76,7 @@ struct lp_fragment_shader_variant_key
unsigned flatshade:1;
unsigned occlusion_count:1;
unsigned resource_1d:1;
+ unsigned depth_clamp:1;
enum pipe_format zsbuf_format;
enum pipe_format cbuf_format[PIPE_MAX_COLOR_BUFS];
diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h
index 29e8cc9..1b5f88e 100644
--- a/src/gallium/include/pipe/p_state.h
+++ b/src/gallium/include/pipe/p_state.h
@@ -130,6 +130,8 @@ struct pipe_rasterizer_state
/**
* When true clip space in the z axis goes from [0..1] (D3D). When false
* [-1, 1] (GL).
+ *
+ * NOTE: D3D will always use depth clamping.
*/
unsigned clip_halfz:1;
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