From e7b22a8d3b61acddf743c0911e6faef624f1afb6 Mon Sep 17 00:00:00 2001
From: enricoturri1966 <enricoturri@seznam.cz>
Date: Mon, 4 Mar 2024 15:02:09 +0100
Subject: [PATCH] libvgcode - Replace 'glVertexAttribIPointer()' with
 'glVertexAttribPointer()' in SegmentTemplate::init() for OpenGL ES

---
 src/libvgcode/CMakeLists.txt          | 8 ++++----
 src/libvgcode/src/SegmentTemplate.cpp | 6 +++++-
 src/libvgcode/src/ShadersES.hpp       | 3 ++-
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/libvgcode/CMakeLists.txt b/src/libvgcode/CMakeLists.txt
index c315cc2848..8bb7e46f50 100644
--- a/src/libvgcode/CMakeLists.txt
+++ b/src/libvgcode/CMakeLists.txt
@@ -44,10 +44,10 @@ set(LIBVGCODE_SOURCES
 	src/ViewerImpl.cpp
 	src/ViewRange.hpp
 	src/ViewRange.cpp
-	# glad OpenGL
-	glad/include/glad/gl.h
-	glad/include/KHR/khrplatform.h
-	glad/src/gl.c
+    # glad OpenGL
+    glad/include/glad/gl.h
+    glad/include/KHR/khrplatform.h
+    glad/src/gl.c
 #    # glad OpenGL ES
 #    glad/include/glad/gles2.h
 #    glad/include/KHR/khrplatform.h
diff --git a/src/libvgcode/src/SegmentTemplate.cpp b/src/libvgcode/src/SegmentTemplate.cpp
index 93779a8472..bc8a1d2001 100644
--- a/src/libvgcode/src/SegmentTemplate.cpp
+++ b/src/libvgcode/src/SegmentTemplate.cpp
@@ -45,7 +45,11 @@ void SegmentTemplate::init()
     glsafe(glBindBuffer(GL_ARRAY_BUFFER, m_vbo_id));
     glsafe(glBufferData(GL_ARRAY_BUFFER, VERTEX_DATA.size() * sizeof(uint8_t), VERTEX_DATA.data(), GL_STATIC_DRAW));
     glsafe(glEnableVertexAttribArray(0));
-    glsafe(glVertexAttribIPointer(0, 1, GL_UNSIGNED_BYTE, sizeof(uint8_t), (const void*)0));
+#if VGCODE_ENABLE_OPENGL_ES
+    glsafe(glVertexAttribPointer(0, 1, GL_UNSIGNED_BYTE, GL_FALSE, 0, (const void*)0));
+#else
+    glsafe(glVertexAttribIPointer(0, 1, GL_UNSIGNED_BYTE, 0, (const void*)0));
+#endif // VGCODE_ENABLE_OPENGL_ES
 
     glsafe(glBindBuffer(GL_ARRAY_BUFFER, curr_array_buffer));
     glsafe(glBindVertexArray(curr_vertex_array));
diff --git a/src/libvgcode/src/ShadersES.hpp b/src/libvgcode/src/ShadersES.hpp
index 0fa9d0f666..e688fa7b4c 100644
--- a/src/libvgcode/src/ShadersES.hpp
+++ b/src/libvgcode/src/ShadersES.hpp
@@ -31,7 +31,7 @@ static const char* Segments_Vertex_Shader_ES =
 "uniform sampler2D height_width_angle_tex;\n"
 "uniform sampler2D color_tex;\n"
 "uniform usampler2D segment_index_tex;\n"
-"in int vertex_id;\n"
+"in float vertex_id_float;\n"
 "out vec3 color;\n"
 "vec3 decode_color(float color) {\n"
 "  int c = int(round(color));\n"
@@ -56,6 +56,7 @@ static const char* Segments_Vertex_Shader_ES =
 "  return (tex_size.y == 1) ? ivec2(id, 0) : ivec2(id % tex_size.x, id / tex_size.x);\n"
 "}\n"
 "void main() {\n"
+"  int vertex_id = int(vertex_id_float);\n"
 "  int id_a = int(texelFetch(segment_index_tex, tex_coord_u(segment_index_tex, gl_InstanceID), 0).r);\n"
 "  int id_b = id_a + 1;\n"
 "  vec3 pos_a = texelFetch(position_tex, tex_coord(position_tex, id_a), 0).xyz;\n"