[Mesa-dev] [PATCH 05/16] nir: add lowering pass for glBitmap
Rob Clark
robdclark at gmail.com
Sat Mar 26 21:02:07 UTC 2016
From: Rob Clark <robclark at freedesktop.org>
Signed-off-by: Rob Clark <robclark at freedesktop.org>
Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>
---
src/compiler/Makefile.sources | 1 +
src/compiler/nir/nir.h | 7 ++
src/compiler/nir/nir_lower_bitmap.c | 166 ++++++++++++++++++++++++++++++++++++
3 files changed, 174 insertions(+)
create mode 100644 src/compiler/nir/nir_lower_bitmap.c
diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index c396128..cb9eee9 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -185,6 +185,7 @@ NIR_FILES = \
nir/nir_liveness.c \
nir/nir_lower_alu_to_scalar.c \
nir/nir_lower_atomics.c \
+ nir/nir_lower_bitmap.c \
nir/nir_lower_clip.c \
nir/nir_lower_drawpixels.c \
nir/nir_lower_global_vars_to_local.c \
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 34635ed..85b28d2 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2269,6 +2269,13 @@ typedef struct nir_lower_drawpixels_options {
void nir_lower_drawpixels(nir_shader *shader,
const nir_lower_drawpixels_options *options);
+typedef struct nir_lower_bitmap_options {
+ unsigned sampler;
+ bool swizzle_xxxx;
+} nir_lower_bitmap_options;
+
+void nir_lower_bitmap(nir_shader *shader, const nir_lower_bitmap_options *options);
+
void nir_lower_atomics(nir_shader *shader,
const struct gl_shader_program *shader_program);
void nir_lower_to_source_mods(nir_shader *shader);
diff --git a/src/compiler/nir/nir_lower_bitmap.c b/src/compiler/nir/nir_lower_bitmap.c
new file mode 100644
index 0000000..3cba69a
--- /dev/null
+++ b/src/compiler/nir/nir_lower_bitmap.c
@@ -0,0 +1,166 @@
+/*
+ * Copyright © 2015 Red Hat
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "nir.h"
+#include "nir_builder.h"
+
+/* Lower glBitmap().
+ *
+ * This is based on the logic in st_get_bitmap_shader() in TGSI compiler.
+ * From st_cb_bitmap.c:
+ *
+ * glBitmaps are drawn as textured quads. The user's bitmap pattern
+ * is stored in a texture image. An alpha8 texture format is used.
+ * The fragment shader samples a bit (texel) from the texture, then
+ * discards the fragment if the bit is off.
+ *
+ * Note that we actually store the inverse image of the bitmap to
+ * simplify the fragment program. An "on" bit gets stored as texel=0x0
+ * and an "off" bit is stored as texel=0xff. Then we kill the
+ * fragment if the negated texel value is less than zero.
+ *
+ * Note that the texture format will be, according to what driver supports,
+ * in order of preference (with swizzle):
+ *
+ * I8_UNORM - .xxxx
+ * A8_UNORM - .000x
+ * L8_UNORM - .xxx1
+ *
+ * If L8_UNORM, options->swizzle_xxxx is true. Otherwise we can just use
+ * the .w comp.
+ *
+ * Run before nir_lower_io.
+ */
+
+typedef struct {
+ const nir_lower_bitmap_options *options;
+ nir_shader *shader;
+ nir_builder b;
+ nir_variable *texcoord;
+} lower_bitmap_state;
+
+static nir_ssa_def *
+get_texcoord(lower_bitmap_state *state)
+{
+ if (state->texcoord == NULL) {
+ nir_variable *texcoord = NULL;
+
+ /* find gl_TexCoord, if it exists: */
+ nir_foreach_variable(var, &state->shader->inputs) {
+ if (strcmp(var->name, "gl_TexCoord") == 0) {
+ texcoord = var;
+ break;
+ }
+ }
+
+ /* otherwise create it: */
+ if (texcoord == NULL) {
+ texcoord = nir_variable_create(state->shader,
+ nir_var_shader_in,
+ glsl_vec4_type(),
+ "gl_TexCoord");
+ texcoord->data.location = VARYING_SLOT_TEX0;
+ }
+
+ state->texcoord = texcoord;
+ }
+ return nir_load_var(&state->b, state->texcoord);
+}
+
+static void
+lower_bitmap(lower_bitmap_state *state, nir_instr *instr)
+{
+ nir_builder *b = &state->b;
+ nir_ssa_def *texcoord;
+ nir_tex_instr *tex;
+ nir_ssa_def *cond;
+ nir_intrinsic_instr *discard;
+
+ b->cursor = nir_before_instr(instr);
+
+ texcoord = get_texcoord(state);
+
+ tex = nir_tex_instr_create(state->shader, 1);
+ tex->op = nir_texop_tex;
+ tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
+ tex->coord_components = 2;
+ tex->sampler_index = state->options->sampler;
+ tex->dest_type = nir_type_float;
+ tex->src[0].src = nir_src_for_ssa(texcoord);
+
+ nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
+ nir_builder_instr_insert(b, &tex->instr);
+
+ /* kill if tex != 0.0.. take .x or .w channel according to format: */
+ cond = nir_f2b(b, nir_channel(b, &tex->dest.ssa,
+ state->options->swizzle_xxxx ? 0 : 3));
+
+ discard = nir_intrinsic_instr_create(state->shader,
+ nir_intrinsic_discard_if);
+ discard->src[0] = nir_src_for_ssa(cond);
+ nir_builder_instr_insert(b, &discard->instr);
+}
+
+static bool
+lower_bitmap_block(nir_block *block, void *_state)
+{
+ lower_bitmap_state *state = _state;
+
+ /* TODO is there a better way to prepend instructions to
+ * the shader? If, hypothetically, there were more than
+ * one function, this probably wouldn't be the right way
+ */
+ nir_foreach_instr_safe(block, instr) {
+ lower_bitmap(state, instr);
+ break;
+ }
+
+ return false;
+}
+
+static void
+lower_bitmap_impl(lower_bitmap_state *state, nir_function_impl *impl)
+{
+ nir_builder_init(&state->b, impl);
+
+ nir_foreach_block(impl, lower_bitmap_block, state);
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+}
+
+void
+nir_lower_bitmap(nir_shader *shader,
+ const nir_lower_bitmap_options *options)
+{
+ lower_bitmap_state state = {
+ .options = options,
+ .shader = shader,
+ };
+
+ assert(shader->stage == MESA_SHADER_FRAGMENT);
+
+ nir_foreach_function(shader, function) {
+ if (function->impl)
+ lower_bitmap_impl(&state, function->impl);
+ }
+}
--
2.5.5
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