void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
memset(mapped_pbo, 0, width * height * bytes_per_pixel);
glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
+ check_error();
glGenTextures(1, &source_image_num);
check_error();
for (unsigned phase = 0; phase < phases.size(); ++phase) {
// Set up inputs and outputs for this phase.
+ glActiveTexture(GL_TEXTURE0);
if (phase == 0) {
// First phase reads from the input texture (which is already bound).
} else {
GL_TEXTURE_2D,
temp_textures[phase % 2],
0);
+ check_error();
}
// We have baked an upside-down transform into the quad coordinates,