Vertex Rendering/Rendering Failure
The GL_INVALID_OPERATION error can happen when issuing any drawing command for many reasons, most of which have little to do with the actual drawing command itself. The following represent conditions you must ensure are valid when issuing a drawing command.
- A non-zero Vertex Array Object must be bound (though no arrays have to be enabled, so it can be a freshly-created vertex array object).
- The current framebuffer must be complete. The Default Framebuffer (if present) is always complete, so this usually happens with Framebuffer Objects.
- The current program object or program pipeline object must be successfully linked and valid for the current state. This includes:
- If there is an active Tessellation Evaluation Shader or Geometry Shader, then there must also be an active Vertex Shader present.
- Any active programs cannot have two or more sampler variables of different types which are associated with the same texture image unit.
- Any active programs cannot have two or more image variables of different types which are associated with the same image unit.
- Program pipeline objects have additional rules. In the case of a unified program, these would all be linker errors, but program pipelines have to check at render-time:
- Programs from one program object cannot come between two shader stages that are defined by different program object. So if you have program A which has a vertex and fragment shader, you cannot put program B into the pipeline with a geometry shader between them.
- The number of active samplers, images, uniform buffers, and shader storage buffers (where applicable) across all images must not exceed the combined implementation-defined limits. This is statically checked by the linker for non-separate programs, but must be render-time checked with program pipelines.
- If a Geometry Shader and a Tessellation Evaluation Shader are present and not linked into the same program, the GS's input primitive type must match the primitive generated by the TES's patch output type.
- If a Tessellation Control Shader is active, a Tessellation Evaluation Shader must also be active.
- Textures used by the current programs' samplers and/or images must be complete.
- If a Geometry Shader is present, the primitive type fed to the GS must be compatible with the primitive input for the GS. If no TES is active, then the mode primitive type from the drawing command must match.
- If Transform Feedback is active, the transform feedback mode must match the applicable primitive mode. That mode is determined as follows:
- If a Geometry Shader is active, then the applicable primitive mode is the GS's output primitive type.
- If no GS is active but a Tessellation Evaluation Shader is active, then the applicable primitive mode is the TES's output primitive type.
- Otherwise, the applicable primitive type is the primitive mode provided to the drawing command.
- mode may be GL_PATCHS if and only if a Tessellation Evaluation Shader is active. And vice versa.
- Buffer objects being read from or written by an OpenGL rendering call must not be mapped in a non-persistent fashion. This includes, but is not limited to:
This list is not comprehensive. If you know of more, please add them here.