Doesn't work for a simple text rendering without a shading program

[yurivict]

I tried to draw a simple 2D OpenGL text and this line https://github.com/rougier/freetype-gl/blob/master/vertex-buffer.c#L396 (glDisableVertexAttribArray( attribute->index );) fails with GL_INVALID_VALUE because index=-1.

This attribute index is hardcoded to be bound to the shader program in https://github.com/rougier/freetype-gl/blob/master/text-buffer.c#L29 (vertex_buffer_new("vertex:3f,tex_coord:2f,color:4f,ashift:1f,agamma:1f" )) but this leaves this index=-1 without such program.

It should be possible to render text without any shading program.

[yurivict]

@rougier You need to add a "simple" testcase that would paint text in 2D in as simple as possible way, without any bells and whistles like shader programs.

[rougier]

I'm not sure to get your point when you say "without shader". Could you post some mokcup user code?

[yurivict]

There should be a function similar to Qt's QGLWidget::renderText() that accepts a font, a string, and paints text with triangles. This would be the simplest use case of painting text with OpenGL.

https://doc.qt.io/qt-5/qglwidget.html#renderText

[rougier]

Ok, I see. This needs to be written and it should not be too difficult provided there is a default font available. Would you be interested in writing such example?