Hello.
I am writing to a 3D texture in a compute shader using the imageStore function. In another compute shader I then need to read from this texture. I would like to be able to set it as a sampler uniform and read it using the texture function but this returns a clear value. However, when I attempt to read with imageLoad after binding the texture as an image, I successfully read the pixels. I am aware this problem fits the description of using gl_MemoryBarrier(GL_SHADER_IMAGE_ACCESS_BIT) in place of gl_MemoryBarrier(GL_TEXTURE_FETCH_BIT) but this doesn't seem to affect the output. Strangely, I only encounter this problem with layered textures.
Here is the code that dispatches the compute shaders and sets up memory barriers:
glUseProgram(inscatter_compute.program_id);
glActiveTexture(GL_TEXTURE0 + TRANSMITTANCE_UNIT);
glBindTexture(GL_TEXTURE_2D, transmittanceTexture);
glUniform1i(glGetUniformLocation(inscatter_compute.program_id, "transmittance_tex"), TRANSMITTANCE_UNIT);
glBindImageTexture(0, deltaSRTexture, 0, GL_TRUE, 0, GL_WRITE_ONLY, GL_RGBA16F);
glBindImageTexture(1, deltaSMTexture, 0, GL_TRUE, 0, GL_WRITE_ONLY, GL_RGBA16F);
glDispatchCompute(16, 8, 8);
glMemoryBarrier(GL_TEXTURE_FETCH_BARRIER_BIT | GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
glUseProgram(copy_inscatter_compute.program_id);
glActiveTexture(GL_TEXTURE0 + DELTA_R_UNIT);
glBindTexture(GL_TEXTURE_3D, deltaSRTexture);
glUniform1i(glGetUniformLocation(copy_inscatter_compute.program_id, "delta_sr_tex"), DELTA_R_UNIT);
glActiveTexture(GL_TEXTURE0 + DELTA_M_UNIT);
glBindTexture(GL_TEXTURE_3D, deltaSMTexture);
glUniform1i(glGetUniformLocation(copy_inscatter_compute.program_id, "delta_sm_tex"), DELTA_M_UNIT);
glBindImageTexture(0, inscatterTexture, 0, GL_TRUE, 0, GL_WRITE_ONLY, GL_RGBA16F);
glDispatchCompute(16, 8, 8);
glMemoryBarrier(GL_TEXTURE_FETCH_BARRIER_BIT | GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
I create all of these textures using glTexStorage3D.
Any input would be appreciated. Thank you.
