I used the code example for creating a triangle with custom shader from the official docs:
import bpy
import gpu
from gpu_extras.batch import batch_for_shader
vertex_shader = '''
uniform mat4 viewProjectionMatrix;
in vec3 position;
out vec3 pos;
void main()
{
pos = position;
gl_Position = viewProjectionMatrix * vec4(position, 1.0f);
}
'''
fragment_shader = '''
uniform float brightness;
in vec3 pos;
out vec4 FragColor;
void main()
{
FragColor = vec4(pos * brightness, 1.0);
}
'''
coords = [(1, 1, 1), (2, 0, 0), (-2, -1, 3)]
shader = gpu.types.GPUShader(vertex_shader, fragment_shader)
batch = batch_for_shader(shader, 'TRIS', {"position": coords})
def draw():
shader.bind()
matrix = bpy.context.region_data.perspective_matrix
shader.uniform_float("viewProjectionMatrix", matrix)
shader.uniform_float("brightness", 0.5)
batch.draw(shader)
bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_VIEW')
The object shows up in the viewport, but doesn't show up in the final render.
Follow up question, in case I can't make such an object render: Can I at least program a GLSL shader for existing geometry that will show up in the final render?