1 files changed, 258 insertions, 0 deletions
diff --git a/intern/gawain/src/gwn_vertex_buffer.c b/intern/gawain/src/gwn_vertex_buffer.c
new file mode 100644
index 00000000000..f621b4c01b9
--- /dev/null
+++ b/intern/gawain/src/gwn_vertex_buffer.c
@@ -0,0 +1,258 @@
+
+// Gawain vertex buffer
+//
+// This code is part of the Gawain library, with modifications
+// specific to integration with Blender.
+//
+// Copyright 2016 Mike Erwin
+//
+// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of
+// the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+#include "gwn_vertex_buffer.h"
+#include "gwn_buffer_id.h"
+#include "gwn_vertex_format_private.h"
+#include <stdlib.h>
+#include <string.h>
+
+#define KEEP_SINGLE_COPY 1
+
+static unsigned vbo_memory_usage;
+
+static GLenum convert_usage_type_to_gl(Gwn_UsageType type)
+	{
+	static const GLenum table[] = {
+		[GWN_USAGE_STREAM] = GL_STREAM_DRAW,
+		[GWN_USAGE_STATIC] = GL_STATIC_DRAW,
+		[GWN_USAGE_DYNAMIC] = GL_DYNAMIC_DRAW
+		};
+	return table[type];
+	}
+
+Gwn_VertBuf* GWN_vertbuf_create(Gwn_UsageType usage)
+	{
+	Gwn_VertBuf* verts = malloc(sizeof(Gwn_VertBuf));
+	GWN_vertbuf_init(verts, usage);
+	return verts;
+	}
+
+Gwn_VertBuf* GWN_vertbuf_create_with_format_ex(const Gwn_VertFormat* format, Gwn_UsageType usage)
+	{
+	Gwn_VertBuf* verts = GWN_vertbuf_create(usage);
+	GWN_vertformat_copy(&verts->format, format);
+	if (!format->packed)
+		VertexFormat_pack(&verts->format);
+	return verts;
+
+	// this function might seem redundant, but there is potential for memory savings here...
+	// TODO: implement those memory savings
+	}
+
+void GWN_vertbuf_init(Gwn_VertBuf* verts, Gwn_UsageType usage)
+	{
+	memset(verts, 0, sizeof(Gwn_VertBuf));
+	verts->usage = usage;
+	verts->dirty = true;
+	}
+
+void GWN_vertbuf_init_with_format_ex(Gwn_VertBuf* verts, const Gwn_VertFormat* format, Gwn_UsageType usage)
+	{
+	GWN_vertbuf_init(verts, usage);
+	GWN_vertformat_copy(&verts->format, format);
+	if (!format->packed)
+		VertexFormat_pack(&verts->format);
+	}
+
+void GWN_vertbuf_discard(Gwn_VertBuf* verts)
+	{
+	if (verts->vbo_id)
+		{
+		GWN_buf_id_free(verts->vbo_id);
+#if VRAM_USAGE
+		vbo_memory_usage -= GWN_vertbuf_size_get(verts);
+#endif
+		}
+
+	if (verts->data)
+		free(verts->data);
+
+	free(verts);
+	}
+
+unsigned GWN_vertbuf_size_get(const Gwn_VertBuf* verts)
+	{
+	return vertex_buffer_size(&verts->format, verts->vertex_ct);
+	}
+
+// create a new allocation, discarding any existing data
+void GWN_vertbuf_data_alloc(Gwn_VertBuf* verts, unsigned v_ct)
+	{
+	Gwn_VertFormat* format = &verts->format;
+	if (!format->packed)
+		VertexFormat_pack(format);
+
+#if TRUST_NO_ONE
+	// catch any unnecessary use
+	assert(verts->vertex_alloc != v_ct || verts->data == NULL);
+#endif
+
+	// only create the buffer the 1st time
+	if (verts->vbo_id == 0)
+		verts->vbo_id = GWN_buf_id_alloc();
+
+	// discard previous data if any
+	if (verts->data)
+		free(verts->data);
+
+#if VRAM_USAGE
+	unsigned new_size = vertex_buffer_size(&verts->format, v_ct);
+	vbo_memory_usage += new_size - GWN_vertbuf_size_get(verts);
+#endif
+
+	verts->dirty = true;
+	verts->vertex_ct = verts->vertex_alloc = v_ct;
+	verts->data = malloc(sizeof(GLubyte) * GWN_vertbuf_size_get(verts));
+	}
+
+// resize buffer keeping existing data
+void GWN_vertbuf_data_resize(Gwn_VertBuf* verts, unsigned v_ct)
+	{
+#if TRUST_NO_ONE
+	assert(verts->data != NULL);
+	assert(verts->vertex_alloc != v_ct);
+#endif
+
+#if VRAM_USAGE
+	unsigned new_size = vertex_buffer_size(&verts->format, v_ct);
+	vbo_memory_usage += new_size - GWN_vertbuf_size_get(verts);
+#endif
+
+	verts->dirty = true;
+	verts->vertex_ct = verts->vertex_alloc = v_ct;
+	verts->data = realloc(verts->data, sizeof(GLubyte) * GWN_vertbuf_size_get(verts));
+	}
+
+// set vertex count but does not change allocation
+// only this many verts will be uploaded to the GPU and rendered
+// this is usefull for streaming data
+void GWN_vertbuf_vertex_count_set(Gwn_VertBuf* verts, unsigned v_ct)
+	{
+#if TRUST_NO_ONE
+	assert(verts->data != NULL); // only for dynamic data
+	assert(v_ct <= verts->vertex_alloc);
+#endif
+
+#if VRAM_USAGE
+	unsigned new_size = vertex_buffer_size(&verts->format, v_ct);
+	vbo_memory_usage += new_size - GWN_vertbuf_size_get(verts);
+#endif
+
+	verts->vertex_ct = v_ct;
+	}
+
+void GWN_vertbuf_attr_set(Gwn_VertBuf* verts, unsigned a_idx, unsigned v_idx, const void* data)
+	{
+	const Gwn_VertFormat* format = &verts->format;
+	const Gwn_VertAttr* a = format->attribs + a_idx;
+
+#if TRUST_NO_ONE
+	assert(a_idx < format->attrib_ct);
+	assert(v_idx < verts->vertex_alloc);
+	assert(verts->data != NULL);
+#endif
+
+	verts->dirty = true;
+	memcpy((GLubyte*)verts->data + a->offset + v_idx * format->stride, data, a->sz);
+	}
+
+void GWN_vertbuf_attr_fill(Gwn_VertBuf* verts, unsigned a_idx, const void* data)
+	{
+	const Gwn_VertFormat* format = &verts->format;
+	const Gwn_VertAttr* a = format->attribs + a_idx;
+
+#if TRUST_NO_ONE
+	assert(a_idx < format->attrib_ct);
+#endif
+
+	const unsigned stride = a->sz; // tightly packed input data
+
+	GWN_vertbuf_attr_fill_stride(verts, a_idx, stride, data);
+	}
+
+void GWN_vertbuf_attr_fill_stride(Gwn_VertBuf* verts, unsigned a_idx, unsigned stride, const void* data)
+	{
+	const Gwn_VertFormat* format = &verts->format;
+	const Gwn_VertAttr* a = format->attribs + a_idx;
+
+#if TRUST_NO_ONE
+	assert(a_idx < format->attrib_ct);
+	assert(verts->data != NULL);
+#endif
+
+	verts->dirty = true;
+	const unsigned vertex_ct = verts->vertex_ct;
+
+	if (format->attrib_ct == 1 && stride == format->stride)
+		{
+		// we can copy it all at once
+		memcpy(verts->data, data, vertex_ct * a->sz);
+		}
+	else
+		{
+		// we must copy it per vertex
+		for (unsigned v = 0; v < vertex_ct; ++v)
+			memcpy((GLubyte*)verts->data + a->offset + v * format->stride, (const GLubyte*)data + v * stride, a->sz);
+		}
+	}
+
+void GWN_vertbuf_attr_get_raw_data(Gwn_VertBuf* verts, unsigned a_idx, Gwn_VertBufRaw *access)
+	{
+	const Gwn_VertFormat* format = &verts->format;
+	const Gwn_VertAttr* a = format->attribs + a_idx;
+
+#if TRUST_NO_ONE
+	assert(a_idx < format->attrib_ct);
+	assert(verts->data != NULL);
+#endif
+
+	verts->dirty = true;
+
+	access->size = a->sz;
+	access->stride = format->stride;
+	access->data = (GLubyte*)verts->data + a->offset;
+	access->data_init = access->data;
+#if TRUST_NO_ONE
+	access->_data_end = access->data_init + (size_t)(verts->vertex_alloc * format->stride);
+#endif
+	}
+
+static void VertBuffer_upload_data(Gwn_VertBuf* verts)
+	{
+	unsigned buffer_sz = GWN_vertbuf_size_get(verts);
+
+	// orphan the vbo to avoid sync
+	glBufferData(GL_ARRAY_BUFFER, buffer_sz, NULL, convert_usage_type_to_gl(verts->usage));
+	// upload data
+	glBufferSubData(GL_ARRAY_BUFFER, 0, buffer_sz, verts->data);
+
+	if (verts->usage == GWN_USAGE_STATIC)
+		{
+		free(verts->data);
+		verts->data = NULL;
+		}
+
+	verts->dirty = false;
+	}
+
+void GWN_vertbuf_use(Gwn_VertBuf* verts)
+	{
+	glBindBuffer(GL_ARRAY_BUFFER, verts->vbo_id);
+
+	if (verts->dirty)
+		VertBuffer_upload_data(verts);
+	}
+
+unsigned GWN_vertbuf_get_memory_usage(void)
+	{
+	return vbo_memory_usage;
+	}