From 392a59a6cc177d66b51b64ad429c69a31e913f1e Mon Sep 17 00:00:00 2001
From: Stanislav Vorobiov <s.vorobiov@samsung.com>
Date: Sat, 1 Mar 2014 20:12:34 +0400
Subject: [PATCH] YaGL: Always use EBO with glDrawElementsXXX

OpenGL 3.1+ core requires that glDrawElementsXXX
be called with EBO bound

Change-Id: Id553c682407ae9da2d0a21fe9065d9eb95122c00
---
 hw/yagl/yagl_apis/gles/yagl_gles_api_ts.c     |  4 ++
 hw/yagl/yagl_apis/gles/yagl_gles_api_ts.h     |  6 ++
 hw/yagl/yagl_apis/gles/yagl_host_gles_calls.c | 63 ++++++++++++++++++-
 3 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.c b/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.c
index 1debb5c425..01e0e3d14b 100644
--- a/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.c
+++ b/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.c
@@ -49,6 +49,10 @@ void yagl_gles_api_ts_cleanup(struct yagl_gles_api_ts *gles_api_ts)
 
         yagl_ensure_ctx(0);
 
+        if (gles_api_ts->ebo) {
+            gles_api_ts->driver->DeleteBuffers(1, &gles_api_ts->ebo);
+        }
+
         for (i = 0; i < gles_api_ts->num_arrays; ++i) {
             gles_api_ts->driver->DeleteBuffers(1,
                                                &gles_api_ts->arrays[i].vbo);
diff --git a/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.h b/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.h
index 8c4ca8610c..f24ad7cbac 100644
--- a/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.h
+++ b/hw/yagl/yagl_apis/gles/yagl_gles_api_ts.h
@@ -55,6 +55,12 @@ struct yagl_gles_api_ts
     struct yagl_gles_array *arrays;
     uint32_t num_arrays;
 
+    /*
+     * See above comments regarding VBO.
+     */
+    GLuint ebo;
+    uint32_t ebo_size;
+
     /*
      * -1 when undecided, 0/1 when decided.
      */
diff --git a/hw/yagl/yagl_apis/gles/yagl_host_gles_calls.c b/hw/yagl/yagl_apis/gles/yagl_host_gles_calls.c
index 17b9b4791c..034f2d3108 100644
--- a/hw/yagl/yagl_apis/gles/yagl_host_gles_calls.c
+++ b/hw/yagl/yagl_apis/gles/yagl_host_gles_calls.c
@@ -153,6 +153,51 @@ static GLuint yagl_gles_bind_array(uint32_t indx,
     return current_vbo;
 }
 
+static GLuint yagl_gles_bind_ebo(const GLvoid *data, int32_t size)
+{
+    GLuint current_ebo;
+    void *ptr;
+
+    YAGL_LOG_FUNC_SET(yagl_gles_bind_ebo);
+
+    if (!gles_api_ts->ebo) {
+        gles_api_ts->driver->GenBuffers(1, &gles_api_ts->ebo);
+    }
+
+    gles_api_ts->driver->GetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING,
+                                     (GLint*)&current_ebo);
+
+    gles_api_ts->driver->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, gles_api_ts->ebo);
+
+    if (size > gles_api_ts->ebo_size) {
+        gles_api_ts->driver->BufferData(GL_ELEMENT_ARRAY_BUFFER,
+                                        size, NULL,
+                                        GL_STREAM_DRAW);
+        gles_api_ts->ebo_size = size;
+    }
+
+    if (yagl_gles_use_map_buffer_range()) {
+        ptr = gles_api_ts->driver->MapBufferRange(GL_ELEMENT_ARRAY_BUFFER,
+                                                  0,
+                                                  size,
+                                                  GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_RANGE_BIT);
+
+        if (ptr) {
+            memcpy(ptr, data, size);
+
+            gles_api_ts->driver->UnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);
+        } else {
+            YAGL_LOG_ERROR("glMapBufferRange failed");
+        }
+    } else {
+        gles_api_ts->driver->Finish();
+        gles_api_ts->driver->BufferSubData(GL_ELEMENT_ARRAY_BUFFER,
+                                           0, size, data);
+    }
+
+    return current_ebo;
+}
+
 static bool yagl_gles_program_get_uniform_type(GLuint program,
                                                GLint location,
                                                GLenum *type)
@@ -550,7 +595,11 @@ void yagl_host_glDrawElements(GLenum mode,
     const GLvoid *indices, int32_t indices_count)
 {
     if (indices) {
-        gles_api_ts->driver->DrawElements(mode, count, type, indices);
+        GLuint current_ebo = yagl_gles_bind_ebo(indices, indices_count);
+
+        gles_api_ts->driver->DrawElements(mode, count, type, NULL);
+
+        gles_api_ts->driver->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, current_ebo);
     } else {
         gles_api_ts->driver->DrawElements(mode, count, type,
                                           (const GLvoid*)(uintptr_t)indices_count);
@@ -608,7 +657,11 @@ void yagl_host_glDrawElementsInstanced(GLenum mode,
     GLsizei primcount)
 {
     if (indices) {
-        gles_api_ts->driver->DrawElementsInstanced(mode, count, type, indices, primcount);
+        GLuint current_ebo = yagl_gles_bind_ebo(indices, indices_count);
+
+        gles_api_ts->driver->DrawElementsInstanced(mode, count, type, NULL, primcount);
+
+        gles_api_ts->driver->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, current_ebo);
     } else {
         gles_api_ts->driver->DrawElementsInstanced(mode,
                                                    count,
@@ -626,7 +679,11 @@ void yagl_host_glDrawRangeElements(GLenum mode,
     const GLvoid *indices, int32_t indices_count)
 {
     if (indices) {
-        gles_api_ts->driver->DrawRangeElements(mode, start, end, count, type, indices);
+        GLuint current_ebo = yagl_gles_bind_ebo(indices, indices_count);
+
+        gles_api_ts->driver->DrawRangeElements(mode, start, end, count, type, NULL);
+
+        gles_api_ts->driver->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, current_ebo);
     } else {
         gles_api_ts->driver->DrawRangeElements(mode, start, end, count, type,
                                                (const GLvoid*)(uintptr_t)indices_count);
-- 
2.34.1