[Mesa-dev] [PATCH 14/14] st/mesa: implement PBO downloads for ReadPixels
Nicolai Hähnle
nhaehnle at gmail.com
Wed May 18 15:25:44 UTC 2016
From: Nicolai Hähnle <nicolai.haehnle at amd.com>
---
src/mesa/state_tracker/st_cb_readpixels.c | 142 +++++++++++++++++++++++++++++-
src/mesa/state_tracker/st_pbo.c | 16 ++++
src/mesa/state_tracker/st_pbo.h | 4 +
3 files changed, 159 insertions(+), 3 deletions(-)
diff --git a/src/mesa/state_tracker/st_cb_readpixels.c b/src/mesa/state_tracker/st_cb_readpixels.c
index 62ddc99..6df3a39 100644
--- a/src/mesa/state_tracker/st_cb_readpixels.c
+++ b/src/mesa/state_tracker/st_cb_readpixels.c
@@ -34,6 +34,7 @@
#include "main/framebuffer.h"
#include "util/u_inlines.h"
#include "util/u_format.h"
+#include "cso_cache/cso_context.h"
#include "st_cb_fbo.h"
#include "st_atom.h"
@@ -42,6 +43,7 @@
#include "st_cb_readpixels.h"
#include "state_tracker/st_cb_texture.h"
#include "state_tracker/st_format.h"
+#include "state_tracker/st_pbo.h"
#include "state_tracker/st_texture.h"
static boolean
@@ -71,11 +73,143 @@ needs_integer_signed_unsigned_conversion(const struct gl_context *ctx,
static bool
try_pbo_readpixels(struct st_context *st, struct st_renderbuffer *strb,
+ bool invert_y,
GLint x, GLint y, GLsizei width, GLsizei height,
enum pipe_format src_format, enum pipe_format dst_format,
const struct gl_pixelstore_attrib *pack, void *pixels)
{
- return false;
+ struct pipe_context *pipe = st->pipe;
+ struct cso_context *cso = st->cso_context;
+ struct pipe_surface *surface = strb->surface;
+ struct pipe_resource *texture = strb->texture;
+ const struct util_format_description *desc;
+ struct st_pbo_addresses addr;
+ struct pipe_framebuffer_state fb;
+ enum pipe_texture_target view_target;
+ bool success = false;
+
+ if (texture->nr_samples > 1)
+ return false;
+
+ desc = util_format_description(dst_format);
+
+ /* Compute PBO addresses */
+ addr.bytes_per_pixel = desc->block.bits / 8;
+ addr.xoffset = x;
+ addr.yoffset = y;
+ addr.width = width;
+ addr.height = height;
+ addr.depth = 1;
+ if (!st_pbo_addresses_pixelstore(st, GL_TEXTURE_2D, false, pack, pixels, &addr))
+ return false;
+
+ cso_save_state(cso, (CSO_BIT_FRAGMENT_SAMPLER_VIEWS |
+ CSO_BIT_FRAGMENT_SAMPLERS |
+ CSO_BIT_FRAGMENT_IMAGE0 |
+ CSO_BIT_VERTEX_ELEMENTS |
+ CSO_BIT_AUX_VERTEX_BUFFER_SLOT |
+ CSO_BIT_FRAMEBUFFER |
+ CSO_BIT_VIEWPORT |
+ CSO_BIT_RASTERIZER |
+ CSO_BIT_DEPTH_STENCIL_ALPHA |
+ CSO_BIT_STREAM_OUTPUTS |
+ CSO_BIT_PAUSE_QUERIES |
+ CSO_BITS_ALL_SHADERS));
+ cso_save_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);
+
+ /* Set up the sampler_view */
+ {
+ struct pipe_sampler_view templ;
+ struct pipe_sampler_view *sampler_view;
+ struct pipe_sampler_state sampler = {0};
+ const struct pipe_sampler_state *samplers[1] = {&sampler};
+
+ u_sampler_view_default_template(&templ, texture, src_format);
+
+ switch (texture->target) {
+ case PIPE_TEXTURE_CUBE:
+ case PIPE_TEXTURE_CUBE_ARRAY:
+ view_target = PIPE_TEXTURE_2D_ARRAY;
+ break;
+ default:
+ view_target = texture->target;
+ break;
+ }
+
+ templ.target = view_target;
+ templ.u.tex.first_level = surface->u.tex.level;
+ templ.u.tex.last_level = templ.u.tex.first_level;
+
+ if (view_target != PIPE_TEXTURE_3D) {
+ templ.u.tex.first_layer = surface->u.tex.first_layer;
+ templ.u.tex.last_layer = templ.u.tex.last_layer;
+ } else {
+ addr.constants.layer_offset = surface->u.tex.first_layer;
+ }
+
+ sampler_view = pipe->create_sampler_view(pipe, texture, &templ);
+ if (sampler_view == NULL)
+ goto fail;
+
+ cso_set_sampler_views(cso, PIPE_SHADER_FRAGMENT, 1, &sampler_view);
+
+ pipe_sampler_view_reference(&sampler_view, NULL);
+
+ cso_set_samplers(cso, PIPE_SHADER_FRAGMENT, 1, samplers);
+ }
+
+ /* Set up destination image */
+ {
+ struct pipe_image_view image;
+
+ memset(&image, 0, sizeof(image));
+ pipe_resource_reference(&image.resource, addr.buffer);
+ image.format = dst_format;
+ image.access = PIPE_IMAGE_ACCESS_WRITE;
+ image.u.buf.first_element = addr.first_element;
+ image.u.buf.last_element = addr.last_element;
+
+ cso_set_shader_images(cso, PIPE_SHADER_FRAGMENT, 0, 1, &image);
+ }
+
+ /* Set up no-attachment framebuffer */
+ memset(&fb, 0, sizeof(fb));
+ fb.width = surface->width;
+ fb.height = surface->height;
+ fb.samples = 1;
+ fb.layers = 1;
+ cso_set_framebuffer(cso, &fb);
+
+ cso_set_viewport_dims(cso, fb.width, fb.height, invert_y);
+
+ if (invert_y)
+ st_pbo_addresses_invert_y(&addr, fb.height);
+
+ {
+ struct pipe_depth_stencil_alpha_state dsa;
+ memset(&dsa, 0, sizeof(dsa));
+ cso_set_depth_stencil_alpha(cso, &dsa);
+ }
+
+ /* Set up the fragment shader */
+ {
+ void *fs = st_pbo_get_download_fs(st, view_target);
+ if (!fs)
+ goto fail;
+
+ cso_set_fragment_shader_handle(cso, fs);
+ }
+
+ success = st_pbo_draw(st, &addr, fb.width, fb.height);
+
+ /* Buffer written via shader images needs explicit synchronization. */
+ pipe->memory_barrier(pipe, PIPE_BARRIER_ALL);
+
+fail:
+ cso_restore_state(cso);
+ cso_restore_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);
+
+ return success;
}
/**
@@ -167,8 +301,10 @@ st_ReadPixels(struct gl_context *ctx, GLint x, GLint y,
goto fallback;
}
- if (_mesa_is_bufferobj(pack->BufferObj)) {
- if (try_pbo_readpixels(st, strb, x, y, width, height,
+ if (st->pbo.download_enabled && _mesa_is_bufferobj(pack->BufferObj)) {
+ if (try_pbo_readpixels(st, strb,
+ st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP,
+ x, y, width, height,
src_format, dst_format,
pack, pixels))
return;
diff --git a/src/mesa/state_tracker/st_pbo.c b/src/mesa/state_tracker/st_pbo.c
index 31a0c19..2ad6f00 100644
--- a/src/mesa/state_tracker/st_pbo.c
+++ b/src/mesa/state_tracker/st_pbo.c
@@ -152,6 +152,22 @@ st_pbo_addresses_pixelstore(struct st_context *st,
return true;
}
+/* For download from a framebuffer, we may have to invert the Y axis. The
+ * setup is as follows:
+ * - set viewport to inverted, so that the position sysval is correct for
+ * texel fetches
+ * - this function adjusts the fragment shader's constant buffer to compute
+ * the correct destination addresses.
+ */
+void
+st_pbo_addresses_invert_y(struct st_pbo_addresses *addr,
+ unsigned viewport_height)
+{
+ addr->constants.xoffset +=
+ (viewport_height - 1 + 2 * addr->constants.yoffset) * addr->constants.stride;
+ addr->constants.stride = -addr->constants.stride;
+}
+
/* Setup all vertex pipeline state, rasterizer state, and fragment shader
* constants, and issue the draw call for PBO upload/download.
*
diff --git a/src/mesa/state_tracker/st_pbo.h b/src/mesa/state_tracker/st_pbo.h
index 14ae6ba..17359c4 100644
--- a/src/mesa/state_tracker/st_pbo.h
+++ b/src/mesa/state_tracker/st_pbo.h
@@ -70,6 +70,10 @@ st_pbo_addresses_pixelstore(struct st_context *st,
const void *pixels,
struct st_pbo_addresses *addr);
+void
+st_pbo_addresses_invert_y(struct st_pbo_addresses *addr,
+ unsigned viewport_height);
+
bool
st_pbo_draw(struct st_context *st, const struct st_pbo_addresses *addr,
unsigned surface_width, unsigned surface_height);
--
2.7.4
More information about the mesa-dev
mailing list