1 files changed, 256 insertions, 0 deletions
diff --git a/source/blender/gpu/intern/gpu_uniform_buffer.cc b/source/blender/gpu/intern/gpu_uniform_buffer.cc
new file mode 100644
index 00000000000..94aa6bd76ab
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+++ b/source/blender/gpu/intern/gpu_uniform_buffer.cc
@@ -0,0 +1,256 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup gpu
+ */
+
+#include "MEM_guardedalloc.h"
+#include <string.h>
+
+#include "BLI_blenlib.h"
+#include "BLI_math_base.h"
+
+#include "gpu_backend.hh"
+#include "gpu_node_graph.h"
+
+#include "GPU_material.h"
+
+#include "GPU_extensions.h"
+
+#include "GPU_uniform_buffer.h"
+#include "gpu_uniform_buffer_private.hh"
+
+/* -------------------------------------------------------------------- */
+/** \name Creation & Deletion
+ * \{ */
+
+namespace blender::gpu {
+
+UniformBuf::UniformBuf(size_t size, const char *name)
+{
+  /* Make sure that UBO is padded to size of vec4 */
+  BLI_assert((size % 16) == 0);
+  BLI_assert(size <= GPU_max_ubo_size());
+
+  size_in_bytes_ = size;
+
+  BLI_strncpy(name_, name, sizeof(name_));
+}
+
+UniformBuf::~UniformBuf()
+{
+  MEM_SAFE_FREE(data_);
+}
+
+}  // namespace blender::gpu
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Uniform buffer from GPUInput list
+ * \{ */
+
+/**
+ * We need to pad some data types (vec3) on the C side
+ * To match the GPU expected memory block alignment.
+ */
+static eGPUType get_padded_gpu_type(LinkData *link)
+{
+  GPUInput *input = (GPUInput *)link->data;
+  eGPUType gputype = input->type;
+  /* Unless the vec3 is followed by a float we need to treat it as a vec4. */
+  if (gputype == GPU_VEC3 && (link->next != NULL) &&
+      (((GPUInput *)link->next->data)->type != GPU_FLOAT)) {
+    gputype = GPU_VEC4;
+  }
+  return gputype;
+}
+
+/**
+ * Returns 1 if the first item should be after second item.
+ * We make sure the vec4 uniforms come first.
+ */
+static int inputs_cmp(const void *a, const void *b)
+{
+  const LinkData *link_a = (const LinkData *)a, *link_b = (const LinkData *)b;
+  const GPUInput *input_a = (const GPUInput *)link_a->data;
+  const GPUInput *input_b = (const GPUInput *)link_b->data;
+  return input_a->type < input_b->type ? 1 : 0;
+}
+
+/**
+ * Make sure we respect the expected alignment of UBOs.
+ * mat4, vec4, pad vec3 as vec4, then vec2, then floats.
+ */
+static void buffer_from_list_inputs_sort(ListBase *inputs)
+{
+/* Only support up to this type, if you want to extend it, make sure static void
+ * inputs_sobuffer_size_compute *inputs) padding logic is correct for the new types. */
+#define MAX_UBO_GPU_TYPE GPU_MAT4
+
+  /* Order them as mat4, vec4, vec3, vec2, float. */
+  BLI_listbase_sort(inputs, inputs_cmp);
+
+  /* Creates a lookup table for the different types; */
+  LinkData *inputs_lookup[MAX_UBO_GPU_TYPE + 1] = {NULL};
+  eGPUType cur_type = static_cast<eGPUType>(MAX_UBO_GPU_TYPE + 1);
+
+  LISTBASE_FOREACH (LinkData *, link, inputs) {
+    GPUInput *input = (GPUInput *)link->data;
+
+    if (input->type == GPU_MAT3) {
+      /* Alignment for mat3 is not handled currently, so not supported */
+      BLI_assert(!"mat3 not supported in UBO");
+      continue;
+    }
+    if (input->type > MAX_UBO_GPU_TYPE) {
+      BLI_assert(!"GPU type not supported in UBO");
+      continue;
+    }
+
+    if (input->type == cur_type) {
+      continue;
+    }
+
+    inputs_lookup[input->type] = link;
+    cur_type = input->type;
+  }
+
+  /* If there is no GPU_VEC3 there is no need for alignment. */
+  if (inputs_lookup[GPU_VEC3] == NULL) {
+    return;
+  }
+
+  LinkData *link = inputs_lookup[GPU_VEC3];
+  while (link != NULL && ((GPUInput *)link->data)->type == GPU_VEC3) {
+    LinkData *link_next = link->next;
+
+    /* If GPU_VEC3 is followed by nothing or a GPU_FLOAT, no need for alignment. */
+    if ((link_next == NULL) || ((GPUInput *)link_next->data)->type == GPU_FLOAT) {
+      break;
+    }
+
+    /* If there is a float, move it next to current vec3. */
+    if (inputs_lookup[GPU_FLOAT] != NULL) {
+      LinkData *float_input = inputs_lookup[GPU_FLOAT];
+      inputs_lookup[GPU_FLOAT] = float_input->next;
+
+      BLI_remlink(inputs, float_input);
+      BLI_insertlinkafter(inputs, link, float_input);
+    }
+
+    link = link_next;
+  }
+#undef MAX_UBO_GPU_TYPE
+}
+
+static inline size_t buffer_size_from_list(ListBase *inputs)
+{
+  size_t buffer_size = 0;
+  LISTBASE_FOREACH (LinkData *, link, inputs) {
+    const eGPUType gputype = get_padded_gpu_type(link);
+    buffer_size += gputype * sizeof(float);
+  }
+  /* Round up to size of vec4. (Opengl Requirement) */
+  size_t alignment = sizeof(float[4]);
+  buffer_size = divide_ceil_u(buffer_size, alignment) * alignment;
+
+  return buffer_size;
+}
+
+static inline void buffer_fill_from_list(void *data, ListBase *inputs)
+{
+  /* Now that we know the total ubo size we can start populating it. */
+  float *offset = (float *)data;
+  LISTBASE_FOREACH (LinkData *, link, inputs) {
+    GPUInput *input = (GPUInput *)link->data;
+    memcpy(offset, input->vec, input->type * sizeof(float));
+    offset += get_padded_gpu_type(link);
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name C-API
+ * \{ */
+
+using namespace blender::gpu;
+
+GPUUniformBuf *GPU_uniformbuf_create_ex(size_t size, const void *data, const char *name)
+{
+  UniformBuf *ubo = GPUBackend::get()->uniformbuf_alloc(size, name);
+  /* Direct init. */
+  if (data != NULL) {
+    ubo->update(data);
+  }
+  return reinterpret_cast<GPUUniformBuf *>(ubo);
+}
+
+/**
+ * Create UBO from inputs list.
+ * Return NULL if failed to create or if \param inputs: is empty.
+ *
+ * \param inputs: ListBase of #BLI_genericNodeN(#GPUInput).
+ */
+GPUUniformBuf *GPU_uniformbuf_create_from_list(ListBase *inputs, const char *name)
+{
+  /* There is no point on creating an UBO if there is no arguments. */
+  if (BLI_listbase_is_empty(inputs)) {
+    return NULL;
+  }
+
+  buffer_from_list_inputs_sort(inputs);
+  size_t buffer_size = buffer_size_from_list(inputs);
+  void *data = MEM_mallocN(buffer_size, __func__);
+  buffer_fill_from_list(data, inputs);
+
+  UniformBuf *ubo = GPUBackend::get()->uniformbuf_alloc(buffer_size, name);
+  /* Defer data upload. */
+  ubo->attach_data(data);
+  return reinterpret_cast<GPUUniformBuf *>(ubo);
+}
+
+void GPU_uniformbuf_free(GPUUniformBuf *ubo)
+{
+  delete reinterpret_cast<UniformBuf *>(ubo);
+}
+
+void GPU_uniformbuf_update(GPUUniformBuf *ubo, const void *data)
+{
+  reinterpret_cast<UniformBuf *>(ubo)->update(data);
+}
+
+void GPU_uniformbuf_bind(GPUUniformBuf *ubo, int slot)
+{
+  reinterpret_cast<UniformBuf *>(ubo)->bind(slot);
+}
+
+void GPU_uniformbuf_unbind(GPUUniformBuf *ubo)
+{
+  reinterpret_cast<UniformBuf *>(ubo)->unbind();
+}
+
+void GPU_uniformbuf_unbind_all(void)
+{
+  /* FIXME */
+}
+
+/** \} */