1 files changed, 622 insertions, 15 deletions

diff --git a/source/blender/gpu/intern/gpu_batch.c b/source/blender/gpu/intern/gpu_batch.c
index 5bfd20e3c8b..90f30930884 100644
--- a/source/blender/gpu/intern/gpu_batch.c
+++ b/source/blender/gpu/intern/gpu_batch.c
@@ -15,32 +15,639 @@
  * 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) 2016 Blender Foundation.
+ * The Original Code is Copyright (C) 2016 by Mike Erwin.
  * All rights reserved.
  *
- * The Original Code is: all of this file.
- *
- * Contributor(s): Mike Erwin
+ * Contributor(s): Blender Foundation
  *
  * ***** END GPL LICENSE BLOCK *****
  */
 
-/** \file blender/gpu/intern/gpu_batch.c
+/** \file blender/gpu/intern/gwn_batch.c
  *  \ingroup gpu
+ *
+ * Gawain geometry batch
+ * Contains VAOs + VBOs + Shader representing a drawable entity.
  */
 
-#include "MEM_guardedalloc.h"
-
-#include "BLI_utildefines.h"
-#include "BLI_rect.h"
-#include "BLI_math.h"
-#include "BLI_polyfill_2d.h"
-#include "BLI_sort_utils.h"
-
-#include "GPU_batch.h"  /* own include */
+#include "GPU_batch.h"
 #include "GPU_batch_presets.h"
+#include "GPU_buffer_id.h"
+#include "GPU_matrix.h"
+#include "GPU_shader.h"
+#include "GPU_vertex_array_id.h"
+
+#include "gpu_batch_private.h"
+#include "gpu_primitive_private.h"
 #include "gpu_shader_private.h"
 
+#include <stdlib.h>
+#include <string.h>
+
+static void batch_update_program_bindings(Gwn_Batch* batch, uint v_first);
+
+void gwn_batch_vao_cache_clear(Gwn_Batch* batch)
+{
+	if (batch->context == NULL) {
+		return;
+	}
+	if (batch->is_dynamic_vao_count) {
+		for (int i = 0; i < batch->dynamic_vaos.count; ++i) {
+			if (batch->dynamic_vaos.vao_ids[i]) {
+				GWN_vao_free(batch->dynamic_vaos.vao_ids[i], batch->context);
+			}
+			if (batch->dynamic_vaos.interfaces[i]) {
+				GWN_shaderinterface_remove_batch_ref((Gwn_ShaderInterface *)batch->dynamic_vaos.interfaces[i], batch);
+			}
+		}
+		free(batch->dynamic_vaos.interfaces);
+		free(batch->dynamic_vaos.vao_ids);
+	}
+	else {
+		for (int i = 0; i < GWN_BATCH_VAO_STATIC_LEN; ++i) {
+			if (batch->static_vaos.vao_ids[i]) {
+				GWN_vao_free(batch->static_vaos.vao_ids[i], batch->context);
+			}
+			if (batch->static_vaos.interfaces[i]) {
+				GWN_shaderinterface_remove_batch_ref((Gwn_ShaderInterface *)batch->static_vaos.interfaces[i], batch);
+			}
+		}
+	}
+	batch->is_dynamic_vao_count = false;
+	for (int i = 0; i < GWN_BATCH_VAO_STATIC_LEN; ++i) {
+		batch->static_vaos.vao_ids[i] = 0;
+		batch->static_vaos.interfaces[i] = NULL;
+	}
+	gwn_context_remove_batch(batch->context, batch);
+	batch->context = NULL;
+}
+
+Gwn_Batch* GWN_batch_create_ex(
+        Gwn_PrimType prim_type, Gwn_VertBuf* verts, Gwn_IndexBuf* elem,
+        uint owns_flag)
+{
+	Gwn_Batch* batch = calloc(1, sizeof(Gwn_Batch));
+	GWN_batch_init_ex(batch, prim_type, verts, elem, owns_flag);
+	return batch;
+}
+
+void GWN_batch_init_ex(
+        Gwn_Batch* batch, Gwn_PrimType prim_type, Gwn_VertBuf* verts, Gwn_IndexBuf* elem,
+        uint owns_flag)
+{
+#if TRUST_NO_ONE
+	assert(verts != NULL);
+#endif
+
+	batch->verts[0] = verts;
+	for (int v = 1; v < GWN_BATCH_VBO_MAX_LEN; ++v) {
+		batch->verts[v] = NULL;
+	}
+	batch->inst = NULL;
+	batch->elem = elem;
+	batch->gl_prim_type = convert_prim_type_to_gl(prim_type);
+	batch->phase = GWN_BATCH_READY_TO_DRAW;
+	batch->is_dynamic_vao_count = false;
+	batch->owns_flag = owns_flag;
+	batch->free_callback = NULL;
+}
+
+/* This will share the VBOs with the new batch. */
+Gwn_Batch* GWN_batch_duplicate(Gwn_Batch* batch_src)
+{
+	Gwn_Batch* batch = GWN_batch_create_ex(GWN_PRIM_POINTS, batch_src->verts[0], batch_src->elem, 0);
+
+	batch->gl_prim_type = batch_src->gl_prim_type;
+	for (int v = 1; v < GWN_BATCH_VBO_MAX_LEN; ++v) {
+		batch->verts[v] = batch_src->verts[v];
+	}
+	return batch;
+}
+
+void GWN_batch_discard(Gwn_Batch* batch)
+{
+	if (batch->owns_flag & GWN_BATCH_OWNS_INDEX) {
+		GWN_indexbuf_discard(batch->elem);
+	}
+	if (batch->owns_flag & GWN_BATCH_OWNS_INSTANCES) {
+		GWN_vertbuf_discard(batch->inst);
+	}
+	if ((batch->owns_flag & ~GWN_BATCH_OWNS_INDEX) != 0) {
+		for (int v = 0; v < GWN_BATCH_VBO_MAX_LEN; ++v) {
+			if (batch->verts[v] == NULL) {
+				break;
+			}
+			if (batch->owns_flag & (1 << v)) {
+				GWN_vertbuf_discard(batch->verts[v]);
+			}
+		}
+	}
+	gwn_batch_vao_cache_clear(batch);
+
+	if (batch->free_callback) {
+		batch->free_callback(batch, batch->callback_data);
+	}
+	free(batch);
+}
+
+void GWN_batch_callback_free_set(Gwn_Batch* batch, void (*callback)(Gwn_Batch*, void*), void* user_data)
+{
+	batch->free_callback = callback;
+	batch->callback_data = user_data;
+}
+
+void GWN_batch_instbuf_set(Gwn_Batch* batch, Gwn_VertBuf* inst, bool own_vbo)
+{
+#if TRUST_NO_ONE
+	assert(inst != NULL);
+#endif
+	/* redo the bindings */
+	gwn_batch_vao_cache_clear(batch);
+
+	if (batch->inst != NULL && (batch->owns_flag & GWN_BATCH_OWNS_INSTANCES)) {
+		GWN_vertbuf_discard(batch->inst);
+	}
+	batch->inst = inst;
+
+	if (own_vbo) {
+		batch->owns_flag |= GWN_BATCH_OWNS_INSTANCES;
+	}
+	else {
+		batch->owns_flag &= ~GWN_BATCH_OWNS_INSTANCES;
+	}
+}
+
+/* Returns the index of verts in the batch. */
+int GWN_batch_vertbuf_add_ex(
+        Gwn_Batch* batch, Gwn_VertBuf* verts,
+        bool own_vbo)
+{
+	/* redo the bindings */
+	gwn_batch_vao_cache_clear(batch);
+
+	for (uint v = 0; v < GWN_BATCH_VBO_MAX_LEN; ++v) {
+		if (batch->verts[v] == NULL) {
+#if TRUST_NO_ONE
+			/* for now all VertexBuffers must have same vertex_len */
+			assert(verts->vertex_len == batch->verts[0]->vertex_len);
+#endif
+			batch->verts[v] = verts;
+			/* TODO: mark dirty so we can keep attrib bindings up-to-date */
+			if (own_vbo)
+				batch->owns_flag |= (1 << v);
+			return v;
+		}
+	}
+
+	/* we only make it this far if there is no room for another Gwn_VertBuf */
+#if TRUST_NO_ONE
+	assert(false);
+#endif
+	return -1;
+}
+
+static GLuint batch_vao_get(Gwn_Batch *batch)
+{
+	/* Search through cache */
+	if (batch->is_dynamic_vao_count) {
+		for (int i = 0; i < batch->dynamic_vaos.count; ++i)
+			if (batch->dynamic_vaos.interfaces[i] == batch->interface)
+				return batch->dynamic_vaos.vao_ids[i];
+	}
+	else {
+		for (int i = 0; i < GWN_BATCH_VAO_STATIC_LEN; ++i)
+			if (batch->static_vaos.interfaces[i] == batch->interface)
+				return batch->static_vaos.vao_ids[i];
+	}
+
+	/* Set context of this batch.
+	 * It will be bound to it until gwn_batch_vao_cache_clear is called.
+	 * Until then it can only be drawn with this context. */
+	if (batch->context == NULL) {
+		batch->context = GWN_context_active_get();
+		gwn_context_add_batch(batch->context, batch);
+	}
+#if TRUST_NO_ONE
+	else {
+		/* Make sure you are not trying to draw this batch in another context. */
+		assert(batch->context == GWN_context_active_get());
+	}
+#endif
+
+	/* Cache miss, time to add a new entry! */
+	GLuint new_vao = 0;
+	if (!batch->is_dynamic_vao_count) {
+		int i; /* find first unused slot */
+		for (i = 0; i < GWN_BATCH_VAO_STATIC_LEN; ++i) 
+			if (batch->static_vaos.vao_ids[i] == 0)
+				break;
+
+		if (i < GWN_BATCH_VAO_STATIC_LEN) {
+			batch->static_vaos.interfaces[i] = batch->interface;
+			batch->static_vaos.vao_ids[i] = new_vao = GWN_vao_alloc();
+		}
+		else {
+			/* Not enough place switch to dynamic. */
+			batch->is_dynamic_vao_count = true;
+			/* Erase previous entries, they will be added back if drawn again. */
+			for (int j = 0; j < GWN_BATCH_VAO_STATIC_LEN; ++j) {
+				GWN_shaderinterface_remove_batch_ref((Gwn_ShaderInterface*)batch->static_vaos.interfaces[j], batch);
+				GWN_vao_free(batch->static_vaos.vao_ids[j], batch->context);
+			}
+			/* Init dynamic arrays and let the branch below set the values. */
+			batch->dynamic_vaos.count = GWN_BATCH_VAO_DYN_ALLOC_COUNT;
+			batch->dynamic_vaos.interfaces = calloc(batch->dynamic_vaos.count, sizeof(Gwn_ShaderInterface*));
+			batch->dynamic_vaos.vao_ids = calloc(batch->dynamic_vaos.count, sizeof(GLuint));
+		}
+	}
+
+	if (batch->is_dynamic_vao_count) {
+		int i; /* find first unused slot */
+		for (i = 0; i < batch->dynamic_vaos.count; ++i)
+			if (batch->dynamic_vaos.vao_ids[i] == 0)
+				break;
+
+		if (i == batch->dynamic_vaos.count) {
+			/* Not enough place, realloc the array. */
+			i = batch->dynamic_vaos.count;
+			batch->dynamic_vaos.count += GWN_BATCH_VAO_DYN_ALLOC_COUNT;
+			batch->dynamic_vaos.interfaces = realloc(batch->dynamic_vaos.interfaces, sizeof(Gwn_ShaderInterface*) * batch->dynamic_vaos.count);
+			batch->dynamic_vaos.vao_ids = realloc(batch->dynamic_vaos.vao_ids, sizeof(GLuint) * batch->dynamic_vaos.count);
+			memset(batch->dynamic_vaos.interfaces + i, 0, sizeof(Gwn_ShaderInterface*) * GWN_BATCH_VAO_DYN_ALLOC_COUNT);
+			memset(batch->dynamic_vaos.vao_ids + i, 0, sizeof(GLuint) * GWN_BATCH_VAO_DYN_ALLOC_COUNT);
+		}
+		batch->dynamic_vaos.interfaces[i] = batch->interface;
+		batch->dynamic_vaos.vao_ids[i] = new_vao = GWN_vao_alloc();
+	}
+
+	GWN_shaderinterface_add_batch_ref((Gwn_ShaderInterface*)batch->interface, batch);
+
+#if TRUST_NO_ONE
+	assert(new_vao != 0);
+#endif
+
+	/* We just got a fresh VAO we need to initialize it. */
+	glBindVertexArray(new_vao);
+	batch_update_program_bindings(batch, 0);
+	glBindVertexArray(0);
+
+	return new_vao;
+}
+
+void GWN_batch_program_set_no_use(Gwn_Batch* batch, uint32_t program, const Gwn_ShaderInterface* shaderface)
+{
+#if TRUST_NO_ONE
+	assert(glIsProgram(shaderface->program));
+	assert(batch->program_in_use == 0);
+#endif
+	batch->interface = shaderface;
+	batch->program = program;
+	batch->vao_id = batch_vao_get(batch);
+}
+
+void GWN_batch_program_set(Gwn_Batch* batch, uint32_t program, const Gwn_ShaderInterface* shaderface)
+{
+	GWN_batch_program_set_no_use(batch, program, shaderface);
+	GWN_batch_program_use_begin(batch); /* hack! to make Batch_Uniform* simpler */
+}
+
+void gwn_batch_remove_interface_ref(Gwn_Batch* batch, const Gwn_ShaderInterface* interface)
+{
+	if (batch->is_dynamic_vao_count) {
+		for (int i = 0; i < batch->dynamic_vaos.count; ++i) {
+			if (batch->dynamic_vaos.interfaces[i] == interface) {
+				GWN_vao_free(batch->dynamic_vaos.vao_ids[i], batch->context);
+				batch->dynamic_vaos.vao_ids[i] = 0;
+				batch->dynamic_vaos.interfaces[i] = NULL;
+				break; /* cannot have duplicates */
+			}
+		}
+	}
+	else {
+		int i;
+		for (i = 0; i < GWN_BATCH_VAO_STATIC_LEN; ++i) {
+			if (batch->static_vaos.interfaces[i] == interface) {
+				GWN_vao_free(batch->static_vaos.vao_ids[i], batch->context);
+				batch->static_vaos.vao_ids[i] = 0;
+				batch->static_vaos.interfaces[i] = NULL;
+				break; /* cannot have duplicates */
+			}
+		}
+	}
+}
+
+static void create_bindings(
+        Gwn_VertBuf* verts, const Gwn_ShaderInterface* interface,
+        uint v_first, const bool use_instancing)
+{
+	const Gwn_VertFormat* format = &verts->format;
+
+	const uint attr_len = format->attr_len;
+	const uint stride = format->stride;
+
+	GWN_vertbuf_use(verts);
+
+	for (uint a_idx = 0; a_idx < attr_len; ++a_idx) {
+		const Gwn_VertAttr* a = format->attribs + a_idx;
+		const GLvoid* pointer = (const GLubyte*)0 + a->offset + v_first * stride;
+
+		for (uint n_idx = 0; n_idx < a->name_len; ++n_idx) {
+			const Gwn_ShaderInput* input = GWN_shaderinterface_attr(interface, a->name[n_idx]);
+
+			if (input == NULL) continue;
+
+			if (a->comp_len == 16 || a->comp_len == 12 || a->comp_len == 8) {
+#if TRUST_NO_ONE
+				assert(a->fetch_mode == GWN_FETCH_FLOAT);
+				assert(a->gl_comp_type == GL_FLOAT);
+#endif
+				for (int i = 0; i < a->comp_len / 4; ++i) {
+					glEnableVertexAttribArray(input->location + i);
+					glVertexAttribDivisor(input->location + i, (use_instancing) ? 1 : 0);
+					glVertexAttribPointer(input->location + i, 4, a->gl_comp_type, GL_FALSE, stride,
+					                      (const GLubyte*)pointer + i * 16);
+				}
+			}
+			else
+				{
+				glEnableVertexAttribArray(input->location);
+				glVertexAttribDivisor(input->location, (use_instancing) ? 1 : 0);
+
+				switch (a->fetch_mode) {
+					case GWN_FETCH_FLOAT:
+					case GWN_FETCH_INT_TO_FLOAT:
+						glVertexAttribPointer(input->location, a->comp_len, a->gl_comp_type, GL_FALSE, stride, pointer);
+						break;
+					case GWN_FETCH_INT_TO_FLOAT_UNIT:
+						glVertexAttribPointer(input->location, a->comp_len, a->gl_comp_type, GL_TRUE, stride, pointer);
+						break;
+					case GWN_FETCH_INT:
+						glVertexAttribIPointer(input->location, a->comp_len, a->gl_comp_type, stride, pointer);
+						break;
+				}
+			}
+		}
+	}
+}
+
+static void batch_update_program_bindings(Gwn_Batch* batch, uint v_first)
+{
+	for (int v = 0; v < GWN_BATCH_VBO_MAX_LEN && batch->verts[v] != NULL; ++v) {
+		create_bindings(batch->verts[v], batch->interface, (batch->inst) ? 0 : v_first, false);
+	}
+	if (batch->inst) {
+		create_bindings(batch->inst, batch->interface, v_first, true);
+	}
+	if (batch->elem) {
+		GWN_indexbuf_use(batch->elem);
+	}
+}
+
+void GWN_batch_program_use_begin(Gwn_Batch* batch)
+{
+	/* NOTE: use_program & done_using_program are fragile, depend on staying in sync with
+	 *       the GL context's active program. use_program doesn't mark other programs as "not used". */
+	/* TODO: make not fragile (somehow) */
+
+	if (!batch->program_in_use) {
+		glUseProgram(batch->program);
+		batch->program_in_use = true;
+	}
+}
+
+void GWN_batch_program_use_end(Gwn_Batch* batch)
+{
+	if (batch->program_in_use) {
+#if PROGRAM_NO_OPTI
+		glUseProgram(0);
+#endif
+		batch->program_in_use = false;
+	}
+}
+
+#if TRUST_NO_ONE
+  #define GET_UNIFORM const Gwn_ShaderInput* uniform = GWN_shaderinterface_uniform(batch->interface, name); assert(uniform);
+#else
+  #define GET_UNIFORM const Gwn_ShaderInput* uniform = GWN_shaderinterface_uniform(batch->interface, name);
+#endif
+
+void GWN_batch_uniform_1ui(Gwn_Batch* batch, const char* name, int value)
+{
+	GET_UNIFORM
+	glUniform1ui(uniform->location, value);
+}
+
+void GWN_batch_uniform_1i(Gwn_Batch* batch, const char* name, int value)
+{
+	GET_UNIFORM
+	glUniform1i(uniform->location, value);
+}
+
+void GWN_batch_uniform_1b(Gwn_Batch* batch, const char* name, bool value)
+{
+	GET_UNIFORM
+	glUniform1i(uniform->location, value ? GL_TRUE : GL_FALSE);
+}
+
+void GWN_batch_uniform_2f(Gwn_Batch* batch, const char* name, float x, float y)
+{
+	GET_UNIFORM
+	glUniform2f(uniform->location, x, y);
+}
+
+void GWN_batch_uniform_3f(Gwn_Batch* batch, const char* name, float x, float y, float z)
+{
+	GET_UNIFORM
+	glUniform3f(uniform->location, x, y, z);
+}
+
+void GWN_batch_uniform_4f(Gwn_Batch* batch, const char* name, float x, float y, float z, float w)
+{
+	GET_UNIFORM
+	glUniform4f(uniform->location, x, y, z, w);
+}
+
+void GWN_batch_uniform_1f(Gwn_Batch* batch, const char* name, float x)
+{
+	GET_UNIFORM
+	glUniform1f(uniform->location, x);
+}
+
+void GWN_batch_uniform_2fv(Gwn_Batch* batch, const char* name, const float data[2])
+{
+	GET_UNIFORM
+	glUniform2fv(uniform->location, 1, data);
+}
+
+void GWN_batch_uniform_3fv(Gwn_Batch* batch, const char* name, const float data[3])
+{
+	GET_UNIFORM
+	glUniform3fv(uniform->location, 1, data);
+}
+
+void GWN_batch_uniform_4fv(Gwn_Batch* batch, const char* name, const float data[4])
+{
+	GET_UNIFORM
+	glUniform4fv(uniform->location, 1, data);
+}
+
+void GWN_batch_uniform_2fv_array(Gwn_Batch* batch, const char* name, const int len, const float *data)
+{
+	GET_UNIFORM
+	glUniform2fv(uniform->location, len, data);
+}
+
+void GWN_batch_uniform_4fv_array(Gwn_Batch* batch, const char* name, const int len, const float *data)
+{
+	GET_UNIFORM
+	glUniform4fv(uniform->location, len, data);
+}
+
+void GWN_batch_uniform_mat4(Gwn_Batch* batch, const char* name, const float data[4][4])
+{
+	GET_UNIFORM
+	glUniformMatrix4fv(uniform->location, 1, GL_FALSE, (const float *)data);
+}
+
+static void primitive_restart_enable(const Gwn_IndexBuf *el)
+{
+	// TODO(fclem) Replace by GL_PRIMITIVE_RESTART_FIXED_INDEX when we have ogl 4.3
+	glEnable(GL_PRIMITIVE_RESTART);
+	GLuint restart_index = (GLuint)0xFFFFFFFF;
+
+#if GWN_TRACK_INDEX_RANGE
+	if (el->index_type == GWN_INDEX_U8)
+		restart_index = (GLuint)0xFF;
+	else if (el->index_type == GWN_INDEX_U16)
+		restart_index = (GLuint)0xFFFF;
+#endif
+
+	glPrimitiveRestartIndex(restart_index);
+}
+
+static void primitive_restart_disable(void)
+{
+	glDisable(GL_PRIMITIVE_RESTART);
+}
+
+void GWN_batch_draw(Gwn_Batch* batch)
+{
+#if TRUST_NO_ONE
+	assert(batch->phase == GWN_BATCH_READY_TO_DRAW);
+	assert(batch->verts[0]->vbo_id != 0);
+#endif
+	GWN_batch_program_use_begin(batch);
+	GPU_matrix_bind(batch->interface); // external call.
+
+	GWN_batch_draw_range_ex(batch, 0, 0, false);
+
+	GWN_batch_program_use_end(batch);
+}
+
+void GWN_batch_draw_range_ex(Gwn_Batch* batch, int v_first, int v_count, bool force_instance)
+{
+#if TRUST_NO_ONE
+	assert(!(force_instance && (batch->inst == NULL)) || v_count > 0); // we cannot infer length if force_instance
+#endif
+	const bool do_instance = (force_instance || batch->inst);
+
+	// If using offset drawing, use the default VAO and redo bindings.
+	if (v_first != 0 && (do_instance || batch->elem)) {
+		glBindVertexArray(GWN_vao_default());
+		batch_update_program_bindings(batch, v_first);
+	}
+	else {
+		glBindVertexArray(batch->vao_id);
+	}
+
+	if (do_instance) {
+		/* Infer length if vertex count is not given */
+		if (v_count == 0) {
+			v_count = batch->inst->vertex_len;
+		}
+
+		if (batch->elem) {
+			const Gwn_IndexBuf* el = batch->elem;
+
+			if (el->use_prim_restart) {
+				primitive_restart_enable(el);
+			}
+#if GWN_TRACK_INDEX_RANGE
+			glDrawElementsInstancedBaseVertex(batch->gl_prim_type,
+			                                  el->index_len,
+			                                  el->gl_index_type,
+			                                  0,
+			                                  v_count,
+			                                  el->base_index);
+#else
+			glDrawElementsInstanced(batch->gl_prim_type, el->index_len, GL_UNSIGNED_INT, 0, v_count);
+#endif
+			if (el->use_prim_restart) {
+				primitive_restart_disable();
+			}
+		}
+		else {
+			glDrawArraysInstanced(batch->gl_prim_type, 0, batch->verts[0]->vertex_len, v_count);
+		}
+	}
+	else {
+		/* Infer length if vertex count is not given */
+		if (v_count == 0) {
+			v_count = (batch->elem) ? batch->elem->index_len : batch->verts[0]->vertex_len;
+		}
+
+		if (batch->elem) {
+			const Gwn_IndexBuf* el = batch->elem;
+
+			if (el->use_prim_restart) {
+				primitive_restart_enable(el);
+			}
+
+#if GWN_TRACK_INDEX_RANGE
+			if (el->base_index) {
+				glDrawRangeElementsBaseVertex(batch->gl_prim_type,
+				                              el->min_index,
+				                              el->max_index,
+				                              v_count,
+				                              el->gl_index_type,
+				                              0,
+				                              el->base_index);
+			}
+			else {
+				glDrawRangeElements(batch->gl_prim_type, el->min_index, el->max_index, v_count, el->gl_index_type, 0);
+			}
+#else
+			glDrawElements(batch->gl_prim_type, v_count, GL_UNSIGNED_INT, 0);
+#endif
+			if (el->use_prim_restart) {
+				primitive_restart_disable();
+			}
+		}
+		else {
+			glDrawArrays(batch->gl_prim_type, v_first, v_count);
+		}
+	}
+
+	/* Performance hog if you are drawing with the same vao multiple time.
+	 * Only activate for debugging. */
+	// glBindVertexArray(0);
+}
+
+/* just draw some vertices and let shader place them where we want. */
+void GWN_draw_primitive(Gwn_PrimType prim_type, int v_count)
+	{
+	/* we cannot draw without vao ... annoying ... */
+	glBindVertexArray(GWN_vao_default());
+
+	GLenum type = convert_prim_type_to_gl(prim_type);
+	glDrawArrays(type, 0, v_count);
+
+	/* Performance hog if you are drawing with the same vao multiple time.
+	 * Only activate for debugging.*/
+	// glBindVertexArray(0);
+	}
+
+
 /* -------------------------------------------------------------------- */
 /** \name Utilities
  * \{ */
@@ -67,4 +674,4 @@ void gpu_batch_exit(void)
 	gpu_batch_presets_exit();
 }
 
-/** \} */
+/** \} */
\ No newline at end of file