Transform feedback mode captures the values of varying variables written by the vertex shader (or, if active, the geometry shader). Transform feedback is said to be active after a call to glBeginTransformFeedback until a subsequent call to glEndTransformFeedback. Transform feedback commands must be paired. If no geometry shader is present, while transform feedback is active the mode parameter to glDrawArrays must match those specified in the following table: Transform Feedback primitiveModeAllowed Render Primitive modesGL_POINTSGL_POINTSGL_LINESGL_LINES, GL_LINE_LOOP, GL_LINE_STRIP, GL_LINES_ADJACENCY, GL_LINE_STRIP_ADJACENCYGL_TRIANGLESGL_TRIANGLES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY If a geometry shader is present, the output primitive type from the geometry shader must match those provided in the following table: Transform Feedback primitiveModeAllowed Geometry Shader Output Primitive TypeGL_POINTSpointsGL_LINESline_stripGL_TRIANGLEStriangle_strip
Geometry shaders, and the GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY, GL_LINES_ADJACENCY and GL_LINE_STRIP_ADJACENCY primtive modes are available only if the GL version is 3.2 or greater.
glBeginTransformFeedback: man4/glBeginTransformFeedback.xml
Transform feedback mode captures the values of varying variables written by the vertex shader (or, if active, the geometry shader). Transform feedback is said to be active after a call to glBeginTransformFeedback until a subsequent call to glEndTransformFeedback. Transform feedback commands must be paired. If no geometry shader is present, while transform feedback is active the mode parameter to glDrawArrays must match those specified in the following table: Transform Feedback primitiveMode Allowed Render Primitive modes GL_POINTS GL_POINTS GL_LINES GL_LINES, GL_LINE_LOOP, GL_LINE_STRIP, GL_LINES_ADJACENCY, GL_LINE_STRIP_ADJACENCY GL_TRIANGLES GL_TRIANGLES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY If a geometry shader is present, the output primitive type from the geometry shader must match those provided in the following table: Transform Feedback primitiveMode Allowed Geometry Shader Output Primitive Type GL_POINTS points GL_LINES line_strip GL_TRIANGLES triangle_strip
Geometry shaders, and the GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY, GL_LINES_ADJACENCY and GL_LINE_STRIP_ADJACENCY primtive modes are available only if the GL version is 3.2 or greater.