AMD Radeon RX 5500 XT, 19.2.2, 20.4.2, 20.5.1 versions checked.
I created minimal sample to reproduce issue, main.cpp attached(uses glfw, glad and glm).
Additional line to zero is drawn in some cases.
Ok case:
glDrawElements( GL_LINE_STRIP, indexes.size() - 2, INDEX_TYPE_GL, (void*)(indexes.data() + 2) );
glDisable( GL_PRIMITIVE_RESTART );
glDrawArrays( GL_LINES, 0, 2 );
Wrong case, data is splitted to separate draw calls:
glDrawElements( GL_LINE_STRIP, 6, INDEX_TYPE_GL, (void*)(indexes.data() + 7) );
glDrawElements( GL_LINE_STRIP, 5, INDEX_TYPE_GL, (void*)( indexes.data() + 2 ) );
glDisable( GL_PRIMITIVE_RESTART );
glDrawArrays( GL_LINES, 0, 2 );
Without glDrawArrays also ok:
glDrawElements( GL_LINE_STRIP, 6, INDEX_TYPE_GL, (void*)(indexes.data() + 7) );
glDrawElements( GL_LINE_STRIP, 5, INDEX_TYPE_GL, (void*)( indexes.data() + 2 ) );
glDisable( GL_PRIMITIVE_RESTART );
I tried to change buffers before glDrawArrays call and to use index buffers. But any draw calls after:
glDrawElements( GL_LINE_STRIP, 6, INDEX_TYPE_GL, (void*)(indexes.data() + 7) );
glDrawElements( GL_LINE_STRIP, 5, INDEX_TYPE_GL, (void*)( indexes.data() + 2 ) );
causes this wrong line to be drawn.
If use 0 as restart index this additional line is drawn not to (0, 0, 0) vertex, but to the first vertex in the current VBO.
