diff --git a/cpp/render/render_opengles.cpp b/cpp/render/render_opengles.cpp
index ed220eb..cf1075c 100644
--- a/cpp/render/render_opengles.cpp
+++ b/cpp/render/render_opengles.cpp
@@ -17,6 +17,7 @@
 #include "render_opengles.hpp"
 #include "../display/display_glx.hpp"
 #include <cstdio>
+#include <cstring>
 
 static rk_shader const * rk_current_shader = nullptr;
 static rk_vertices const * rk_current_vertices = nullptr;
@@ -257,16 +258,20 @@ rk_vertices_t rk_create_vertices(
         return nullptr;
     }
     unsigned vertex_size = 0;
+    unsigned nattribs = 0;
     for (rk_vertex_format const * f = format; *f; ++f) {
         switch (*f & RK_VERTEX_FORMAT_MASK) {
             case RK_VERTEX_FORMAT_VEC3_FLOAT:
-                vertex_size += sizeof(rk_vec3);
+                vertex_size += sizeof(rk_vec3_float);
+                nattribs += 1;
                 break;
             case RK_VERTEX_FORMAT_VEC3_INT10:
-                vertex_size += sizeof(rk_int);
+                vertex_size += sizeof(rk_vec3_int10);
+                nattribs += 1;
                 break;
             case RK_VERTEX_FORMAT_VEC3_UINT10:
-                vertex_size += sizeof(rk_uint);
+                vertex_size += sizeof(rk_vec3_uint10);
+                nattribs += 1;
                 break;
             default:
                 rk_printf("rk_create_vertices(): invalid format.");
@@ -279,35 +284,39 @@ rk_vertices_t rk_create_vertices(
         return nullptr;
     }
     rk_vertices * const vertices = new rk_vertices;
+    vertices->vertex_size = vertex_size;
     glGenVertexArrays(1, &vertices->array);
     glBindVertexArray(vertices->array);
     glGenBuffers(1, &vertices->vertices);
     glBindBuffer(GL_ARRAY_BUFFER, vertices->vertices);
     glBufferData(GL_ARRAY_BUFFER, nvertices * vertex_size, _vertices, GL_STATIC_DRAW);
     glBindBuffer(GL_ARRAY_BUFFER, 0);
-    vertices->vertex_size = vertex_size;
+    glBindVertexBuffer(RK_VERTICES_BINDING, vertices->vertices, 0, vertices->vertex_size);
+    for (unsigned attrib = 0; attrib < nattribs; ++attrib) {
+        glEnableVertexAttribArray(attrib);
+    }
     vertices->layout = 0;
     unsigned offset = 0;
-    for (rk_vertex_format const * f = format; *f; ++f, ++vertices->layout) {
-        glEnableVertexAttribArray(vertices->layout);
+    for (rk_vertex_format const * f = format; *f; ++f) {
         GLboolean const norm = (*f & RK_VERTEX_FORMAT_NORMALIZE) != 0;
         switch (*f & RK_VERTEX_FORMAT_MASK) {
             case RK_VERTEX_FORMAT_VEC3_FLOAT:
-                glVertexAttribFormat(vertices->layout, 3, GL_FLOAT, norm, offset);
-                offset += sizeof(rk_vec3);
+                glVertexAttribFormat(vertices->layout++, 3, GL_FLOAT, GL_FALSE, offset);
+                offset += sizeof(rk_vec3_float);
                 break;
             case RK_VERTEX_FORMAT_VEC3_INT10:
-                glVertexAttribFormat(vertices->layout, 4, GL_INT_2_10_10_10_REV, norm, offset);
-                offset += sizeof(rk_int);
+                glVertexAttribFormat(vertices->layout++, 4, GL_INT_2_10_10_10_REV, norm, offset);
+                offset += sizeof(rk_vec3_int10);
                 break;
             case RK_VERTEX_FORMAT_VEC3_UINT10:
-                glVertexAttribFormat(vertices->layout, 4, GL_UNSIGNED_INT_2_10_10_10_REV, norm, offset);
-                offset += sizeof(rk_uint);
+                glVertexAttribFormat(vertices->layout++, 4, GL_UNSIGNED_INT_2_10_10_10_REV, norm, offset);
+                offset += sizeof(rk_vec3_uint10);
                 break;
         }
-        glVertexAttribBinding(vertices->layout, RK_VERTICES_BINDING);
     }
-    glBindVertexBuffer(RK_VERTICES_BINDING, vertices->vertices, 0, vertices->vertex_size);
+    for (unsigned attrib = 0; attrib < nattribs; ++attrib) {
+        glVertexAttribBinding(attrib, RK_VERTICES_BINDING);
+    }
     glGenBuffers(1, &vertices->indices);
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vertices->indices);
     glBufferData(GL_ELEMENT_ARRAY_BUFFER, nindices * sizeof(rk_ushort), indices, GL_STATIC_DRAW);
@@ -402,27 +411,33 @@ rk_batch_t rk_create_batch(
     unsigned nparams = 0;
     unsigned params_size = 0;
     unsigned packed_size = 0;
+    unsigned nattribs = 0;
     for (rk_param_format const * f = params_format; *f; ++f, ++nparams) {
         switch (*f & RK_PARAM_FORMAT_MASK) {
             case RK_PARAM_FORMAT_VEC3_FLOAT:
                 params_size += sizeof(rk_vec3_float);
                 packed_size += sizeof(rk_vec3_float);
+                nattribs += 1;
                 break;
             case RK_PARAM_FORMAT_VEC3_SHORT:
                 params_size += sizeof(rk_vec3_float);
                 packed_size += sizeof(rk_vec3_short);
+                nattribs += 1;
                 break;
             case RK_PARAM_FORMAT_VEC3_INT10:
                 params_size += sizeof(rk_vec3_float);
                 packed_size += sizeof(rk_vec3_int10);
+                nattribs += 1;
                 break;
             case RK_PARAM_FORMAT_MAT3_FLOAT:
                 params_size += sizeof(rk_mat3_float);
                 packed_size += sizeof(rk_mat3_float);
+                nattribs += 3;
                 break;
             case RK_PARAM_FORMAT_MAT3_INT10:
                 params_size += sizeof(rk_mat3_float);
                 packed_size += sizeof(rk_mat3_int10);
+                nattribs += 3;
                 break;
             default:
                 rk_printf("rk_create_batch(): invalid param format.");
@@ -430,6 +445,7 @@ rk_batch_t rk_create_batch(
                 break;
         }
     }
+    glBindVertexArray(vertices->array);
     rk_batch * batch = new rk_batch;
     batch->size = max_size;
     batch->nparams = nparams;
@@ -437,14 +453,32 @@ rk_batch_t rk_create_batch(
     batch->packed_size = packed_size;
     batch->indices = new rk_ushort[max_size];
     batch->commands = new rk_command[max_size * sizeof(rk_command)];
+    memset(batch->commands, 0, max_size * sizeof(rk_command));
+    if (rk_MultiDrawElementsIndirect) {
+        glGenBuffers(1, &batch->commands_buffer);
+        glBindBuffer(GL_DRAW_INDIRECT_BUFFER, batch->commands_buffer);
+        glBufferData(GL_DRAW_INDIRECT_BUFFER, max_size * sizeof(rk_command), batch->commands, GL_DYNAMIC_DRAW);
+        glBindBuffer(GL_DRAW_INDIRECT_BUFFER, 0);
+    } else {
+        batch->commands_buffer = 0;
+    }
+    batch->packers = nullptr;
+    batch->params = nullptr;
     if (nparams) {
         batch->packers = new rk_packer[nparams];
         batch->params = new rk_ubyte[max_size * packed_size];
+        memset(batch->params, 0, max_size * packed_size);
         glGenBuffers(1, &batch->params_buffer);
+        glBindBuffer(GL_ARRAY_BUFFER, batch->params_buffer);
+        glBufferData(GL_ARRAY_BUFFER, max_size * batch->packed_size, batch->params, GL_DYNAMIC_DRAW);
+        glBindBuffer(GL_ARRAY_BUFFER, 0);
+        glBindVertexBuffer(RK_PARAMS_BINDING, batch->params_buffer, 0, batch->packed_size);
+        for (unsigned attrib = vertices->layout; attrib < vertices->layout + nattribs; ++attrib) {
+            glEnableVertexAttribArray(attrib);
+        }
         rk_packer * packer = batch->packers;
         unsigned layout = vertices->layout;
         unsigned offset = 0;
-        glBindVertexArray(vertices->array);
         for (rk_param_format const * f = params_format; *f; ++f, ++packer) {
             GLboolean const norm = (*f & RK_PARAM_FORMAT_NORMALIZE) != 0;
             switch (*f & RK_PARAM_FORMAT_MASK) {
@@ -497,17 +531,14 @@ rk_batch_t rk_create_batch(
             }
             offset += packer->dst_incr;
         }
-        for (unsigned attrib = vertices->layout; attrib < layout; ++attrib) {
-            glEnableVertexAttribArray(attrib);
+        for (unsigned attrib = vertices->layout; attrib < vertices->layout + nattribs; ++attrib) {
             glVertexAttribBinding(attrib, RK_PARAMS_BINDING);
         }
         glVertexBindingDivisor(RK_PARAMS_BINDING, 1);
-        glBindVertexBuffer(RK_PARAMS_BINDING, batch->params_buffer, 0, batch->packed_size);
-        glBindVertexArray(0);
-    }
-    if (rk_MultiDrawElementsIndirect) {
-        glGenBuffers(1, &batch->commands_buffer);
+    } else {
+        batch->params_buffer = 0;
     }
+    glBindVertexArray(0);
     return batch;
 }
 
@@ -687,21 +718,23 @@ void rk_draw_batch(
     if (!ninstances) {
         return;
     }
-    unsigned const ncommands = rk_batch_build_commands(batch, ninstances, meshes);
     if (rk_MultiDrawElementsIndirect) {
         glBindBuffer(GL_DRAW_INDIRECT_BUFFER, batch.commands_buffer);
-        glBufferData(GL_DRAW_INDIRECT_BUFFER, ncommands * sizeof(rk_command), batch.commands, GL_STREAM_DRAW);
+    }
+    if (batch.nparams) {
+        glBindBuffer(GL_ARRAY_BUFFER, batch.params_buffer);
+    }
+    unsigned const ncommands = rk_batch_build_commands(batch, ninstances, meshes);
+    if (rk_MultiDrawElementsIndirect) {
+        glBufferSubData(GL_DRAW_INDIRECT_BUFFER, 0, ncommands * sizeof(rk_command), batch.commands);
     }
     if (batch.nparams) {
         rk_batch_pack(batch, ninstances, params);
-        glBindBuffer(GL_ARRAY_BUFFER, batch.params_buffer);
-        glBufferData(GL_ARRAY_BUFFER, ninstances * batch.packed_size, batch.params, GL_STREAM_DRAW);
-        glBindBuffer(GL_ARRAY_BUFFER, 0);
+        glBufferSubData(GL_ARRAY_BUFFER, 0, ninstances * batch.packed_size, batch.params);
     }
     if (rk_DrawElementsInstancedBaseInstance) {
         if (rk_MultiDrawElementsIndirect) {
             rk_MultiDrawElementsIndirect(GL_TRIANGLES, GL_UNSIGNED_SHORT, nullptr, ncommands, sizeof(rk_command));
-            glBindBuffer(GL_DRAW_INDIRECT_BUFFER, 0);
         } else {
             rk_command const * const last_command = batch.commands + ncommands;
             for (rk_command const * command = batch.commands; command < last_command; ++command) {
@@ -725,6 +758,12 @@ void rk_draw_batch(
                 command->ninstances);
         }
     }
+    if (rk_MultiDrawElementsIndirect) {
+        glBindBuffer(GL_DRAW_INDIRECT_BUFFER, 0);
+    }
+    if (batch.nparams) {
+        glBindBuffer(GL_ARRAY_BUFFER, 0);
+    }
 }
 
 void rk_unselect_vertices(
diff --git a/cpp/render/render_opengles.hpp b/cpp/render/render_opengles.hpp
index 1ae4048..61ef1de 100644
--- a/cpp/render/render_opengles.hpp
+++ b/cpp/render/render_opengles.hpp
@@ -65,6 +65,7 @@ struct rk_vec3_short {
 };
 
 typedef rk_int rk_vec3_int10;
+typedef rk_uint rk_vec3_uint10;
 
 struct rk_mat3_float {
     rk_vec3_float x;
@@ -124,8 +125,8 @@ struct rk_batch {
     rk_command * commands;
     rk_packer * packers;
     rk_ubyte * params;
-    GLuint params_buffer;
     GLuint commands_buffer;
+    GLuint params_buffer;
 };
 
 #endif // _RK_ENGINE_RENDER_OPENGLES_H